Integrated single-nuclei and spatial transcriptomic analysis reveals propagation of early acute vein harvest and distension injury signaling pathways following arterial implantation

Background

Vein graft failure (VGF) following cardiovascular bypass surgery results in significant patient morbidity and cost to the healthcare system. Vein graft injury can occur during autogenous vein harvest and preparation, as well as after implantation into the arterial system, leading to the development of intimal hyperplasia, vein graft stenosis, and, ultimately, bypass graft failure. While previous studies have identified maladaptive pathways that occur shortly after implantation, the specific signaling pathways that occur during vein graft preparation are not well defined and may result in a cumulative impact on VGF. We, therefore, aimed to elucidate the response of the vein conduit wall during harvest and following implantation, probing the key maladaptive pathways driving graft failure with the overarching goal of identifying therapeutic targets for biologic intervention to minimize these natural responses to surgical vein graft injury.

Methods

Employing a novel approach to investigating vascular pathologies, we harnessed both single-nuclei RNA-sequencing (snRNA-seq) and spatial transcriptomics (ST) analyses to profile the genomic effects of vein grafts after harvest and distension, then compared these findings to vein grafts obtained 24 hours after carotid-cartoid vein bypass implantation in a canine model (n=4).

Results

Spatial transcriptomic analysis of canine cephalic vein after initial conduit harvest and distention revealed significant enrichment of pathways (P < 0.05) involved in the activation of endothelial cells (ECs), fibroblasts (FBs), and vascular smooth muscle cells (VSMCs), namely pathways responsible for cellular proliferation and migration and platelet activation across the intimal and medial layers, cytokine signaling within the adventitial layer, and extracellular matrix (ECM) remodeling throughout the vein wall. Subsequent snRNA-seq analysis supported these findings and further unveiled distinct EC and FB subpopulations with significant upregulation (P < 0.00001) of markers related to endothelial injury response and cellular activation of ECs, FBs, and VSMCs. Similarly, in vein grafts obtained 24 hours after arterial bypass, there was an increase in myeloid cell, protomyofibroblast, injury-response EC, and mesenchymal-transitioning EC subpopulations with a concomitant decrease in homeostatic ECs and fibroblasts. Among these markers were genes previously implicated in vein graft injury, including VCAN (versican), FBN1 (fibrillin-1), and VEGFC (vascular endothelial growth factor C), in addition to novel genes of interest such as GLIS3 (GLIS family zinc finger 3) and EPHA3 (ephrin-A3). These genes were further noted to be driving the expression of genes implicated in vascular remodeling and graft failure, such as IL-6, TGFBR1, SMAD4, and ADAMTS9. By integrating the ST and snRNA-seq datasets, we highlighted the spatial architecture of the vein graft following distension, wherein activated and mesenchymal-transitioning ECs, myeloid cells, and FBs were notably enriched in the intima and media of distended veins. Lastly, intercellular communication network analysis unveiled the critical roles of activated ECs, mesenchymal transitioning ECs, protomyofibroblasts, and VSMCs in upregulating signaling pathways associated with cellular proliferation (MDK, PDGF, VEGF), transdifferentiation (Notch), migration (ephrin, semaphorin), ECM remodeling (collagen, laminin, fibronectin), and inflammation (thrombospondin), following distension.

Conclusions

Vein conduit harvest and distension elicit a prompt genomic response facilitated by distinct cellular subpopulations heterogeneously distributed throughout the vein wall. This response was found to be further exacerbated following vein graft implantation, resulting in a cascade of maladaptive gene regulatory networks. Together, these results suggest that distension initiates the upregulation of pathological pathways that may ultimately contribute to bypass graft failure and presents potential early targets warranting investigation for targeted therapies. This work highlights the first applications of single-nuclei and spatial transcriptomic analyses to investigate venous pathologies, underscoring the utility of these methodologies and providing a foundation for future investigations.

Indoximod-based chemo-immunotherapy for pediatric brain tumors: A first-in-children phase I trial

BACKGROUND

Recurrent brain tumors are the leading cause of cancer death in children. Indoleamine 2,3-dioxygenase (IDO) is a targetable metabolic checkpoint that, in preclinical models, inhibits anti-tumor immunity following chemotherapy.

METHODS

We conducted a phase I trial (NCT02502708) of the oral IDO-pathway inhibitor indoximod in children with recurrent brain tumors or newly diagnosed diffuse intrinsic pontine glioma (DIPG). Separate dose-finding arms were performed for indoximod in combination with oral temozolomide (200 mg/m2/day x 5 days in 28-day cycles), or with palliative conformal radiation. Blood samples were collected at baseline and monthly for single-cell RNA-sequencing with paired single-cell T cell receptor sequencing.

RESULTS

Eighty-one patients were treated with indoximod-based combination therapy. Median follow-up was 52 months (range 39-77 months). Maximum tolerated dose was not reached, and the pediatric dose of indoximod was determined as 19.2 mg/kg/dose, twice daily. Median overall survival was 13.3 months (n = 68, range 0.2-62.7) for all patients with recurrent disease and 14.4 months (n = 13, range 4.7-29.7) for DIPG. The subset of n = 26 patients who showed evidence of objective response (even a partial or mixed response) had over 3-fold longer median OS (25.2 months, range 5.4-61.9, p = 0.006) compared to n = 37 nonresponders (7.3 months, range 0.2-62.7). Four patients remain free of active disease longer than 36 months. Single-cell sequencing confirmed emergence of new circulating CD8 T cell clonotypes with late effector phenotype.

CONCLUSIONS

Indoximod was well tolerated and could be safely combined with chemotherapy and radiation. Encouraging preliminary evidence of efficacy supports advancing to Phase II/III trials for pediatric brain tumors.

The Simple prEservatioN of Single cElls method for cryopreservation enables the generation of single-cell immune profiles from whole blood

Introduction

Current multistep methods utilized for preparing and cryopreserving single-cell suspensions from blood samples for single-cell RNA sequencing (scRNA-seq) are time-consuming, requiring trained personnel and special equipment, so limiting their clinical adoption. We developed a method, Simple prEservatioN of Single cElls (SENSE), for single-step cryopreservation of whole blood (WB) along with granulocyte depletion during single-cell assay, to generate high quality single-cell profiles (SCP).

Methods

WB was cryopreserved using the SENSE method and peripheral blood mononuclear cells (PBMCs) were isolated and cryopreserved using the traditional density-gradient method (PBMC method) from the same blood sample (n=6). The SCPs obtained from both methods were processed using a similar pipeline and quality control parameters. Further, entropy calculation, differential gene expression, and cellular communication analysis were performed to compare cell types and subtypes from both methods.

Results

Highly viable (86.3 ± 1.51%) single-cell suspensions (22,353 cells) were obtained from the six WB samples cryopreserved using the SENSE method. In-depth characterization of the scRNA-seq datasets from the samples processed with the SENSE method yielded high-quality profiles of lymphoid and myeloid cell types which were in concordance with the profiles obtained with classical multistep PBMC method processed samples. Additionally, the SENSE method cryopreserved samples exhibited significantly higher T-cell enrichment, enabling deeper characterization of T-cell subtypes. Overall, the SENSE and PBMC methods processed samples exhibited transcriptional, and cellular communication network level similarities across cell types with no batch effect except in myeloid lineage cells.

Discussion

Comparative analysis of scRNA-seq datasets obtained with the two cryopreservation methods i.e., SENSE and PBMC methods, yielded similar cellular and molecular profiles, confirming the suitability of the former method's incorporation in clinics/labs for cryopreserving and obtaining high-quality single-cells for conducting critical translational research.

Single-cell RNA sequencing distinctly characterizes the wide heterogeneity in pediatric mixed phenotype acute leukemia

BACKGROUND

Mixed phenotype acute leukemia (MPAL), a rare subgroup of leukemia characterized by blast cells with myeloid and lymphoid lineage features, is difficult to diagnose and treat. A better characterization of MPAL is essential to understand the subtype heterogeneity and how it compares with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Therefore, we performed single-cell RNA sequencing (scRNAseq) on pediatric MPAL bone marrow (BM) samples to develop a granular map of the MPAL blasts and microenvironment landscape.

METHODS

We analyzed over 40,000 cells from nine pediatric MPAL BM samples to generate a single-cell transcriptomic landscape of B/myeloid (B/My) and T/myeloid (T/My) MPAL. Cells were clustered using unsupervised single-cell methods, and malignant blast and immune clusters were annotated. Differential expression analysis was performed to identify B/My and T/My MPAL blast-specific signatures by comparing transcriptome profiles of MPAL with normal BM, AML, and ALL. Gene set enrichment analysis (GSEA) was performed, and significantly enriched pathways were compared in MPAL subtypes.

RESULTS

B/My and T/My MPAL blasts displayed distinct blast signatures. Transcriptomic analysis revealed that B/My MPAL profile overlaps with B-ALL and AML samples. Similarly, T/My MPAL exhibited overlap with T-ALL and AML samples. Genes overexpressed in both MPAL subtypes' blast cells compared to AML, ALL, and healthy BM included MAP2K2 and CD81. Subtype-specific genes included HBEGF for B/My and PTEN for T/My. These marker sets segregated bulk RNA-seq AML, ALL, and MPAL samples based on expression profiles. Analysis comparing T/My MPAL to ETP, near-ETP, and non-ETP T-ALL, showed that T/My MPAL had greater overlap with ETP-ALL cases. Comparisons among MPAL subtypes between adult and pediatric samples showed analogous transcriptomic landscapes of corresponding subtypes. Transcriptomic differences were observed in the MPAL samples based on response to induction chemotherapy, including selective upregulation of the IL-16 pathway in relapsed samples.

CONCLUSIONS

We have for the first time described the single-cell transcriptomic landscape of pediatric MPAL and demonstrated that B/My and T/My MPAL have distinct scRNAseq profiles from each other, AML, and ALL. Differences in transcriptomic profiles were seen based on response to therapy, but larger studies will be needed to validate these findings.

Single-cell analysis reveals altered tumor microenvironments of relapse- and remission-associated pediatric acute myeloid leukemia

Acute myeloid leukemia (AML) microenvironment exhibits cellular and molecular differences among various subtypes. Here, we utilize single-cell RNA sequencing (scRNA-seq) to analyze pediatric AML bone marrow (BM) samples from diagnosis (Dx), end of induction (EOI), and relapse timepoints. Analysis of Dx, EOI scRNA-seq, and TARGET AML RNA-seq datasets reveals an AML blasts-associated 7-gene signature (CLEC11A, PRAME, AZU1, NREP, ARMH1, C1QBP, TRH), which we validate on independent datasets. The analysis reveals distinct clusters of Dx relapse- and continuous complete remission (CCR)-associated AML-blasts with differential expression of genes associated with survival. At Dx, relapse-associated samples have more exhausted T cells while CCR-associated samples have more inflammatory M1 macrophages. Post-therapy EOI residual blasts overexpress fatty acid oxidation, tumor growth, and stemness genes. Also, a post-therapy T-cell cluster associated with relapse samples exhibits downregulation of MHC Class I and T-cell regulatory genes. Altogether, this study deeply characterizes pediatric AML relapse- and CCR-associated samples to provide insights into the BM microenvironment landscape.

Taxane chemotherapy induces stromal injury that leads to breast cancer dormancy escape

A major cause of cancer recurrence following chemotherapy is cancer dormancy escape. Taxane-based chemotherapy is standard of care in breast cancer treatment aimed at killing proliferating cancer cells. Here, we demonstrate that docetaxel injures stromal cells, which release protumor cytokines, IL-6 and granulocyte colony stimulating factor (G-CSF), that in turn invoke dormant cancer outgrowth both in vitro and in vivo. Single-cell transcriptomics shows a reprogramming of awakened cancer cells including several survival cues such as stemness, chemoresistance in a tumor stromal organoid (TSO) model, as well as an altered tumor microenvironment (TME) with augmented protumor immune signaling in a syngeneic mouse breast cancer model. IL-6 plays a role in cancer cell proliferation, whereas G-CSF mediates tumor immunosuppression. Pathways and differential expression analyses confirmed MEK as the key regulatory molecule in cancer cell outgrowth and survival. Antibody targeting of protumor cytokines (IL-6, G-CSF) or inhibition of cytokine signaling via MEK/ERK pathway using selumetinib prior to docetaxel treatment prevented cancer dormancy outgrowth suggesting a novel therapeutic strategy to prevent cancer recurrence.

Pediatric T-cell acute lymphoblastic leukemia blast signature and MRD associated immune environment changes defined by single cell transcriptomics analysis

Different driver mutations and/or chromosomal aberrations and dysregulated signaling interactions between leukemia cells and the immune microenvironment have been implicated in the development of T-cell acute lymphoblastic leukemia (T-ALL). To better understand changes in the bone marrow microenvironment and signaling pathways in pediatric T-ALL, bone marrows collected at diagnosis (Dx) and end of induction therapy (EOI) from 11 patients at a single center were profiled by single cell transcriptomics (10 Dx, 5 paired EOI, 1 relapse). T-ALL blasts were identified by comparison with healthy bone marrow cells. T-ALL blast-associated gene signature included SOX4, STMN1, JUN, HES4, CDK6, ARMH1 among the most significantly overexpressed genes, some of which are associated with poor prognosis in children with T-ALL. Transcriptome profiles of the blast cells exhibited significant inter-patient heterogeneity. Post induction therapy expression profiles of the immune cells revealed significant changes. Residual blast cells in MRD+ EOI samples exhibited significant upregulation (P < 0.01) of PD-1 and RhoGDI signaling pathways. Differences in cellular communication were noted in the presence of residual disease in T cell and hematopoietic stem cell compartments in the bone marrow. Together, these studies generate new insights and expand our understanding of the bone marrow landscape in pediatric T-ALL.

Cross center single-cell RNA sequencing study of the immune microenvironment in rapid progressing multiple myeloma

Despite advancements in understanding the pathophysiology of Multiple Myeloma (MM), the cause of rapid progressing disease in a subset of patients is still unclear. MM's progression is facilitated by complex interactions with the surrounding bone marrow (BM) cells, forming a microenvironment that supports tumor growth and drug resistance. Understanding the immune microenvironment is key to identifying factors that promote rapid progression of MM. To accomplish this, we performed a multi-center single-cell RNA sequencing (scRNA-seq) study on 102,207 cells from 48 CD138^- BM samples collected at the time of disease diagnosis from 18 patients with either rapid progressing (progression-free survival (PFS) < 18 months) or non-progressing (PFS > 4 years) disease. Comparative analysis of data from three centers demonstrated similar transcriptome profiles and cell type distributions, indicating subtle technical variation in scRNA-seq, opening avenues for an expanded multicenter trial. Rapid progressors depicted significantly higher enrichment of GZMK⁺ and TIGIT⁺ exhausted CD8⁺ T-cells (P = 0.022) along with decreased expression of cytolytic markers (PRF1, GZMB, GNLY). We also observed a significantly higher enrichment of M2 tolerogenic macrophages in rapid progressors and activation of pro-proliferative signaling pathways, such as BAFF, CCL, and IL16. On the other hand, non-progressive patients depicted higher enrichment for immature B Cells (i.e., Pre/Pro B cells), with elevated expression for markers of B cell development (IGLL1, SOX4, DNTT). This multi-center study identifies the enrichment of various pro-tumorigenic cell populations and pathways in those with rapid progressing disease and further validates the robustness of scRNA-seq data generated at different study centers.

Abstract A35: MERTK inhibition induces an anti-leukemia dendritic cell – T cell axis while TYRO3 inhibition protects by a separate mechanism

The TAM family receptor tyrosine kinases TYRO3, AXL and MERTK are potential therapeutic targets in a variety of cancers. In our previous studies, MERTK inhibition in the leukemia microenvironment significantly prolonged survival in a syngeneic B-cell acute leukemia (B-ALL) model, implicating MERTK as a promising immuno-oncology target. Strikingly, Mertk-/- mice were almost completely protected against leukemia. Here, we probed the mechanisms of anti-leukemia immunity mediated by MERTK inhibition and evaluated roles for TYRO3 and AXL in the leukemia microenvironment. Single cell RNA sequencing and flow cytometry studies revealed an increase in CD8α+ dendritic cells (DCs) with enhanced antigen-presentation capacity in naïve and leukemia-bearing Mertk-/- mice. These cells were also increased in leukemic wild type (WT) mice treated with the MERTK inhibitor MRX-2843 (currently in phase I/Ib clinical trials). Additionally, CD8+ T cells expressing high levels of the T cell exhaustion marker Tox were decreased in mice treated with MRX-2843, implicating a CD8α+ DC – T cell axis in the anti-leukemia immune response stimulated by MERTK inhibition. Indeed, combined depletion of CD8+ T cells and CD8α+ DCs completely abrogated the anti-leukemia response in Mertk-/- mice, while immunity remained partially intact in mice with selective depletion of CD8+ T cells. Similarly, protection from leukemia was abrogated in Mertk-/- scid mice, which lack functional B and T cells and have defects in DC function. These data demonstrate a critical immunosuppressive role for MERTK in DCs of the leukemia microenvironment. Similar to Mertk-/- mice, B-ALL growth was almost completely prevented in Tyro3-/- mice, while Axl-/- did not impact leukemogenesis, implicating TYRO3, but not AXL, as an additional immunotherapeutic target. However, in contrast to Mertk-/- mice, CD8α+ DCs with enhanced antigen-presentation capacity were not significantly increased in Tyro3-/- mice compared to WT, indicating differences in the underlying mechanisms by which MERTK and TYRO3 contribute to the immunosurveillance of leukemia cells. Indeed, in vivo depletion experiments confirmed differential roles for MERTK and TYRO3 in the leukemia microenvironment. In contrast to Mertk-/- mice, selective depletion of CD8+ T cells completely abrogated protection from leukemia in Tyro3-/- mice, indicating a mechanism less dependent on DCs. Together, these findings reveal novel and distinct mechanistic insights into the immunosuppressive roles for MERTK and TYRO3 in the leukemia microenvironment, demonstrate a critical role for MERTK in DC activity, and validate a similar mechanism mediated by MRX-2843. Thus, these studies provide strong rationale for development of MERTK and/or TYRO3-targeted immunotherapies for treatment of acute leukemia.

Citation Format: Justus M Huelse, Swati S Bhasin, Kristen M Jacobsen, Beena E Thomas, Madison L Chimenti, Travon A Baxter, Xiaodong Wang, Stephen V Frye, Curtis J Henry, H. Shelton Earp, Manoj Bhasin, Deborah DeRyckere, Douglas K Graham. MERTK inhibition induces an anti-leukemia dendritic cell – T cell axis while TYRO3 inhibition protects by a separate mechanism [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy; 2022 Oct 21-24; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2022;10(12 Suppl):Abstract nr A35.

Comprehensive characterization of the multiple myeloma immune microenvironment using integrated scRNA-seq, CyTOF, and CITE-seq analysis

As part of the Multiple Myeloma Research Foundation (MMRF) immune atlas pilot project, we compared immune cells of Multiple Myeloma (MM) bone marrow samples from 18 patients assessed by single-cell RNA-seq (scRNA-seq), mass cytometry (CyTOF), and Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-seq) to understand the concordance of measurements among single-cell techniques. Cell type abundances are relatively consistent across the three approaches, while variations are observed in T cells, macrophages, and monocytes. Concordance and correlation analysis of cell type marker gene expression across different modalities highlighted the importance of choosing cell type marker genes best suited to particular modalities. By integrating data from these three assays, we found International Staging System (ISS) stage 3 patients exhibited decreased CD4+ T/ CD8+ T cells ratio. Moreover, we observed upregulation of RAC2 and PSMB9, in NK cells of fast progressors (FP) compared to those of non-progressors (NP), as revealed by both scRNA-seq and CITE-seq RNA measurement. This detailed examination of the immune microenvironment in MM using multiple single cell technologies revealed markers associated with MM rapid progression which will be further characterized by the full-scale immune atlas project.

The cost-effectiveness of a resilience-based psychosocial intervention for HIV prevention among MSM in India

OBJECTIVE

MSM in India are at a high risk for HIV infection given psychosocial challenges, sexual orientation stress, and stigma. We examined the cost-effectiveness of a novel resilience-based psychosocial intervention for MSM in India.

DESIGN

We parameterized a validated microsimulation model (CEPAC) with India-specific data and results from a randomized trial and examined two strategies for MSM: status quo HIV care ( SQ ), and a trial-based psychosocial intervention ( INT ) focused on building resilience to stress, improving mental health, and reducing condomless anal sex (CAS).

METHODS

We projected lifetime clinical and economic outcomes for MSM without HIV initially. Intervention effectiveness, defined as reduction in self-reported CAS, was estimated at 38%; cost was $49.37/participant. We used a willingness-to-pay threshold of US$2100 (2019 Indian per capita GDP) per year of life saved (YLS) to define cost-effectiveness. We also assessed the 5-year budget impact of offering this intervention to 20% of Indian MSM.

RESULTS

Model projections showed the intervention would avert 2940 HIV infections among MSM over 10 years. Over a lifetime horizon, the intervention was cost-effective (ICER = $900/YLS). Results were most sensitive to intervention effectiveness and cost; the intervention remained cost-effective under plausible ranges of these parameters. Offering this intervention in the public sector would require an additional US$28 M over 5 years compared with SQ .

CONCLUSION

A resilience-based psychosocial intervention integrated with HIV risk reduction counseling among MSM in India would reduce HIV infections and be cost-effective. Programs using this approach should be expanded as a part of comprehensive HIV prevention in India.

Measuring tuberculosis patient perceived quality of care in public and public–private mix settings in India: an instrument development and validation study

Background

At present, there are no validated quantitative scales available to measure patient-centred quality of care in health facilities providing services for tuberculosis (TB) patients in India and low-income and middle-income countries.

Methods

Initial themes and items reflective of TB patient’s perceived quality of care were developed using qualitative interviews. Content adequacy of the items were ascertained through Content validity Index (CVI) and content validity ratio (CVR). Pilot testing of the questionnaire for assessing validity and reliability was undertaken among 714 patients with TB. Sampling adequacy and sphericity were tested by Kaiser-Meyer-Olkin and Bartlett’s test, respectively. Exploratory and confirmatory factor analysis was undertaken to test validity. Cronbach’s α and test–retest scores were used to test reliability.

Results

A 32-item tool measuring patient-perceived quality of TB distributed across five domains was developed initially based on a CVI and CVR cut-off score of 0.78 and cognitive interviews with patients with TB. Bartlett’s test results showed a strong significance f (χ²=3756 and p<0.001) and Kaiser-Meyer-Olkin was measured to be 0.698 highlighting data adequacy and correlation between the variables. Exploratory factor analysis with varimax rotation extracted 4 factors related to 14 items with Eigen values >1 which accounted for 60.9% of the total variance of items. Correlation (z-value >1.96) between items and factors was highly significant and Cronbach’s α was acceptable for the global scale (0.76) for the four factors. Intraclass correlation coefficient and the test retest scores for four factors were (<0.001) significant.

Conclusion

We validated a measurement tool for patient-perceived quality of care for TB (PPQCTB) which measured the patient’s satisfaction with healthcare provider and services. PPQCTB tool could enrich quality of care evaluation frameworks for TB health services in India.

Abstract 240: MERTK inhibition induces an anti-leukemia dendritic cell - T cell axis while TYRO3 inhibition protects through a separate mechanism

The TAM family receptor tyrosine kinases TYRO3, AXL and MERTK are potential therapeutic targets in a variety of cancers. In previous studies, inhibition of MERTK decreased PD-1 checkpoint proteins in the leukemia microenvironment and prolonged survival in a syngeneic BCR-ABL+/Arf-/- B-cell acute leukemia model, implicating MERTK as a promising immune-oncology target in leukemia. Strikingly, Mertk-/- mice were largely protected from leukemia. In our current studies, Tyro3-/- almost completely prevented development of leukemia, comparable to Mertk-/-, while Axl-/- mice died with similar timing to wild type (WT) mice (20-40 days). These data demonstrate differential roles for TAM kinases in the anti-leukemia immune response. Depletion studies were conducted to evaluate potential roles for T cells and dendritic cells (DCs) in anti-leukemia immunity in Mertk-/- mice. Selective depletion of CD8+ T cells abrogated protection from leukemia in Mertk-/- mice, but survival was still prolonged relative to WT. Thus, while CD8+ T cells were required for complete protection from leukemia, the anti-leukemia response remained partially intact even in the absence of CD8+ T cells, implicating an innate immune mechanism. Indeed, combined depletion of CD8+ T cell and CD8α+ DC subsets completely abrogated the anti-leukemic effects in Mertk-/- mice, revealing a critical immunosuppressive role for MERTK in DCs in the leukemia microenvironment. In contrast to Mertk-/- mice, selective depletion of CD8+ T cells completely abrogated protection from leukemia in Tyro3-/- mice, indicating a mechanism less dependent on DCs. Similarly, single cell RNA sequencing revealed CD8+ DCs with a more mature and antigen-presenting phenotype in Mertk-/- mice compared to WT, while antigen-presenting DCs were not increased in Tyro3-/- mice. Single cell sequencing data also suggest induction of an anti-leukemic DC - T cell axis in WT leukemic mice treated with the MERTK-selective inhibitor MRX-2843. DCs were nearly absent in leukemic bone marrow from saline-treated mice and were dramatically increased in response to treatment with MRX-2843. Treatment with MRX-2843 also decreased the incidence of CD8+ T cells expressing high levels of Tox, which has been associated with T cell exhaustion. These changes coincided with decreased leukemic blasts, even in the context of established disease.Together, our findings support a model whereby MERTK inhibition promotes DC function and CD8+ T cell activity, leading to anti-leukemia immunity. In contrast, anti-leukemia immunity in response to TYRO3 inhibition is less dependent on DCs. Differential roles for the TAM kinases in the leukemia microenvironment provide rationale for development of MERTK and/or TYRO3 targeted immunotherapies to treat acute leukemia.

Citation Format: Justus M. Huelse, Swati S. Bhasin, Beena E. Thomas, Madison L. Chimenti, Xiaodong Wang, Stephen V. Frye, H. Shelton Earp, Manoj Bhasin, Deborah DeRyckere, Douglas K. Graham. MERTK inhibition induces an anti-leukemia dendritic cell - T cell axis while TYRO3 inhibition protects through a separate mechanism [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 240.

Single cell transcriptomic landscape of diabetic foot ulcers

Diabetic foot ulceration (DFU) is a devastating complication of diabetes whose pathogenesis remains incompletely understood. Here, we profile 174,962 single cells from the foot, forearm, and peripheral blood mononuclear cells using single-cell RNA sequencing. Our analysis shows enrichment of a unique population of fibroblasts overexpressing MMP1, MMP3, MMP11, HIF1A, CHI3L1, and TNFAIP6 and increased M1 macrophage polarization in the DFU patients with healing wounds. Further, analysis of spatially separated samples from the same patient and spatial transcriptomics reveal preferential localization of these healing associated fibroblasts toward the wound bed as compared to the wound edge or unwounded skin. Spatial transcriptomics also validates our findings of higher abundance of M1 macrophages in healers and M2 macrophages in non-healers. Our analysis provides deep insights into the wound healing microenvironment, identifying cell types that could be critical in promoting DFU healing, and may inform novel therapeutic approaches for DFU treatment.

Measuring Tuberculosis Medication Adherence: A Comparison of Multiple Approaches in Relation to Urine Isoniazid Metabolite Testing Within a Cohort Study in India

Background

Nonadherence to tuberculosis medications is associated with poor outcomes. However, measuring adherence in practice is challenging. In this study, we evaluated the accuracy of multiple tuberculosis adherence measures.

Methods

We enrolled adult Indians with drug-susceptible tuberculosis who were monitored using 99DOTS, a cellphone-based technology. During an unannounced home visit with each participant, we assessed adherence using a pill estimate, 4-day dose recall, a last missed dose question, and urine isoniazid metabolite testing. We estimated the area under the receiver operating characteristic curve (AUC) for each alternate measure in comparison to urine testing. 99DOTS data were analyzed using patient-reported doses alone and patient- and provider-reported doses, the latter reflecting how 99DOTS is implemented in practice. We assessed each measure's operating characteristics, with particular interest in specificity-that is, the percentage of participants detected as being nonadherent by each alternate measure, among those who were nonadherent by urine testing.

Results

Compared with urine testing, alternate measures had the following characteristics: 99DOTS patient-reported doses alone (area under the curve [AUC], 0.65; specificity, 70%; 95% CI, 58%-81%), 99DOTS patient- and provider-reported doses (AUC, 0.61; specificity, 33%; 95% CI, 22%-45%), pill estimate (AUC, 0.55; specificity, 21%; 95% CI, 12%-32%), 4-day recall (AUC, 0.60; specificity, 23%; 95% CI, 14%-34%), and last missed dose question (AUC, 0.65; specificity, 52%; 95% CI, 40%-63%).

Conclusions

Alternate measures missed detecting at least 30% of people who were nonadherent by urine testing. The last missed dose question performed similarly to 99DOTS using patient-reported doses alone. Tuberculosis programs should evaluate the feasibility of integrating more accurate, objective measures, such as urine testing, into routine care.

Mycobacterium tuberculosis strain lineage in mixed tribal population across India and Andaman Nicobar Island

In India, the tribal population constitutes almost 8.6% of the nation's total population. Despite their large presence, there are only a few reports available on Mycobacterium tuberculosis (M. tb) strain prevalence in Indian tribal communities considering the mobile nature of this population and also the influence of the mainstream populations they coexist within many areas for their livelihood. This study attempts to provide critical information pertaining to the TB strain diversity, its public health implications, and distribution among the tribal population in eleven Indian states and Andaman & Nicobar (A&N) Island. The study employed a population-based molecular approach. Clinical isolates were received from 66 villages (10 states and Island) and these villages were selected by implying situation analysis. A total of 78 M. tb clinical isolates were received from 10 different states and A&N Island. Among these, 16 different strains were observed by spoligotyping technique. The major M. tb strains spoligotype belong to the Beijing, CAS1_DELHI, and EAI5 family of M. tb strains followed by EAI1_SOM, EAI6_BGD1, LAM3, LAM6, LAM9, T1, T2, U strains. Drug-susceptibility testing (DST) results showed almost 15.4% of clinical isolates found to be resistant to isoniazid (INH) or rifampicin (RMP) + INH. Predominant multidrug-resistant (MDR-TB) isolates seem to be Beijing strain. Beijing, CAS1_DELHI, EAI3_IND, and EAI5 were the principal strains infecting mixed tribal populations across India. Despite the small sample size, this study has demonstrated higher diversity among the TB strains with significant MDR-TB findings. Prevalence of Beijing MDR-TB strains in Central, Southern, Eastern India and A&N Island indicates the transmission of the TB strains.

Psychosocial impact of COVID-19 pandemic on healthcare workers in India & their perceptions on the way forward - A qualitative study

Background & objectives:

The healthcare system across the world has been overburdened due to the COVID-19 pandemic impacting healthcare workers (HCWs) in different ways. The present study provides an insight into the psychosocial challenges faced by the HCWs related to their work, family and personal well-being and the associated stigmas. Additionally, the coping mechanisms adopted by them and their perceptions on the interventions to address these challenges were also explored.

Methods:

A qualitative study was conducted between September and December 2020 through in-depth telephonic interviews using an interview guide among 111 HCWs who were involved in COVID-19 management across 10 States in India.

Results:

HCWs report major changes in work-life environment that included excessive workload with erratic timings accentuated with the extended duration of inconvenient personal protection equipment usage, periods of quarantine and long durations of separation from family. Family-related issues were manifold; the main challenge being separated from family, the challenge of caregiving, especially for females with infants and children, and fears around infecting family. Stigma from the community and peers fuelled by the fear of infection was manifested through avoidance and rejection. Coping strategies included peer, family support and the positive experiences manifested as appreciation and recognition for their contribution during the pandemic.

Interpretation & conclusions:

The study demonstrates the psychological burden of HCWs engaged with COVID-19 care services. The study findings point to need-based psychosocial interventions at the organizational, societal and individual levels. This includes a conducive working environment involving periodic evaluation of the HCW problems, rotation of workforce by engaging more staff, debunking of false information, community and HCW involvement in COVID sensitization to allay fears and prevent stigma associated with COVID-19 infection/transmission and finally need-based psychological support for them and their families.

Understanding why at-risk population segments do not seek care for tuberculosis: a precision public health approach in South India

INTRODUCTION

Delaying care-seeking for tuberculosis (TB) symptoms is a major contributor to mortality, leading to worse outcomes and spread. To reduce delays, it is essential to identify barriers to care-seeking and target populations most at risk of delaying. Previous work identifies barriers only in people within the health system, often long after initial care-seeking.

METHODS

We conducted a community-based survey of 84 625 households in Chennai, India, to identify 1667 people with TB-indicative symptoms in 2018-2019. Cases were followed prospectively to observe care-seeking behaviour. We used a comprehensive survey to identify care-seeking drivers, then performed multivariate analyses to identify care-seeking predictors. To identify profiles of individuals most at risk to delay care-seeking, we segmented the sample using unsupervised clustering. We then estimated the per cent of the TB-diagnosed population in Chennai in each segment.

RESULTS

Delayed care-seeking characteristics include smoking, drinking, being employed, preferring different facilities than the community, believing to be at lower risk of TB and believing TB is common. Respondents who reported fever or unintended weight loss were more likely to seek care. Clustering analysis revealed seven population segments differing in care-seeking, from a retired/unemployed/disabled cluster, where 70% promptly sought care, to a cluster of employed men who problem-drink and smoke, where only 42% did so. Modelling showed 54% of TB-diagnosed people who delay care-seeking might belong to the latter segment, which is most likely to acquire TB and least likely to promptly seek care.

CONCLUSION

Interventions to increase care-seeking should move from building general awareness to addressing treatment barriers such as lack of time and low-risk perception. Care-seeking interventions should address specific beliefs through a mix of educational, risk perception-targeting and social norms-based campaigns. Employed men who problem-drink and smoke are a prime target for interventions. Reducing delays in this group could dramatically reduce TB spread.

Acceptability of the Medication Event Reminder Monitor for Promoting Adherence to Multidrug-Resistant Tuberculosis Therapy in Two Indian Cities: Qualitative Study of Patients and Health Care Providers

Background

Patients with multidrug-resistant tuberculosis (MDR-TB) face challenges adhering to medications, given that treatment is prolonged and has a high rate of adverse effects. The Medication Event Reminder Monitor (MERM) is a digital pillbox that provides pill-taking reminders and facilitates the remote monitoring of medication adherence.

Objective

This study aims to assess the MERM’s acceptability to patients and health care providers (HCPs) during pilot implementation in India’s public sector MDR-TB program.

Methods

From October 2017 to September 2018, we conducted qualitative interviews with patients who were undergoing MDR-TB therapy and were being monitored with the MERM and HCPs in the government program in Chennai and Mumbai. Interview transcripts were independently coded by 2 researchers and analyzed to identify the emergent themes. We organized findings by using the Unified Theory of Acceptance and Use of Technology (UTAUT), which outlines 4 constructs that predict technology acceptance—performance expectancy, effort expectancy, social influence, and facilitating conditions.

Results

We interviewed 65 patients with MDR-TB and 10 HCPs. In patient interviews, greater acceptance of the MERM was related to perceptions that the audible and visual reminders improved medication adherence and that remote monitoring reduced the frequency of clinic visits (performance expectancy), that the device’s organization and labeling of medications made it easier to take them correctly (effort expectancy), that the device facilitated positive family involvement in the patient’s care (social influences), and that remote monitoring made patients feel more cared for by the health system (facilitating conditions). Lower patient acceptance was related to problems with the durability of the MERM’s cardboard construction and difficulties with portability and storage because of its large size (effort expectancy), concerns regarding stigma and the disclosure of patients’ MDR-TB diagnoses (social influences), and the incorrect understanding of the MERM because of suboptimal counseling (facilitating conditions). In their interviews, HCPs reported that MERM implementation resulted in fewer in-person interactions with patients and thus allowed HCPs to dedicate more time to other tasks, which improved job satisfaction.

Conclusions

Several features of the MERM support its acceptability among patients with MDR-TB and HCPs, and some barriers to patient use could be addressed by improving the design of the device. However, some barriers, such as disease-related stigma, are more difficult to modify and may limit use of the MERM among some patients with MDR-TB. Further research is needed to assess the accuracy of MERM for measuring adherence, its effectiveness for improving treatment outcomes, and patients’ sustained use of the device in larger scale implementation.

Prevalence of pulmonary tuberculosis among the tribal populations in India

Importance

There is no concrete evidence on the burden of TB among the tribal populations across India except for few studies mainly conducted in Central India with a pooled estimation of 703/100,000 with a high degree of heterogeneity.

Objective

To estimate the prevalence of TB among the tribal populations in India.

Design, participants, setting

A survey using a multistage cluster sampling design was conducted between April 2015 and March 2020 covering 88 villages (clusters) from districts with over 70% tribal majority populations in 17 States across 6 zones of India. The sample populations included individuals ≥15 years old.

Main outcome and measures

Eligible participants who were screened through an interview for symptoms suggestive of pulmonary TB (PTB); Two sputum specimens were examined by smear and culture. Prevalence was estimated after multiple imputations for non-coverage and a correction factor of 1.31 was then applied to account for non-inclusion of X-ray screening.

Results

A total of 74532 (81.0%) of the 92038 eligible individuals were screened; 2675 (3.6%) were found to have TB symptoms or h/o ATT. The overall prevalence of PTB was 432 per 100,000 populations. The PTB prevalence per 100,000 populations was highest 625 [95% CI: 496–754] in the central zone and least 153 [95% CI: 24–281] in the west zone. Among the 17 states that were covered in this study, Odisha recorded the highest prevalence of 803 [95% CI: 504–1101] and Jammu and Kashmir the lowest 127 [95% CI: 0–310] per 100,000 populations. Findings from multiple logistic regression analysis reflected that those aged 35 years and above, with BMI <18.5 Kgs /m², h/o ATT, smoking, and/or consuming alcohol had a higher risk of bacteriologically positive PTB. Weight loss was relatively more important symptom associated with tuberculosis among this tribal populations followed by night sweats, blood in sputum, and fever.

Conclusion and relevance

The overall prevalence of PTB among tribal groups is higher than the general populations with a wide variation of prevalence of PTB among the tribal groups at zone and state levels. These findings call for strengthening of the TB control efforts in tribal areas to reduce TB prevalence through tribal community/site-specific intervention programs.

Understanding health care-seeking behaviour of the tribal population in India among those with presumptive TB symptoms

BACKGROUND AND OBJECTIVES

Understanding the drivers for care-seeking among those who present with symptoms of TB is crucial for early diagnosis of TB and prompt treatment, which will in turn halt further TB transmission. While TB is a challenge among the tribal population, little is known about the care-seeking behaviour and the factors influencing care-seeking behaviour among the tribal population across India.

METHODOLOGY

This community-based descriptive study was carried out in 17 states of India across 6 zones, covering 88 villages from tribal districts with over 70% tribal population. The sample population included individuals ≥15 years old who were screened through an interview for symptoms suggestive of pulmonary TB (PTB), currently and/or previously on anti-TB treatment. Those with symptoms were then assessed on their health-seeking behavior using a semi-structured interview schedule.

RESULTS

Among 74532 eligible participants screened for symptoms suggestive of TB, 2675 (3.6%) were found to be presumptive TB cases. Of them, 659 (24.6%) sought care for their symptoms. While 48.2% sought care after a week, 19.3% sought care after one month or more, with no significant difference in the first point of care; 46.9% approaching a private and 46.7% a public facility. The significant factors influencing care-seeking behaviour were knowledge on TB (OR: 4.64 (3.70-5.83), p < 0.001), age<35 years (OR: 1.60 (1.28-2.00), p < 0.001), co-morbidities like asthma (OR: 1.80 (1.38-2.35), p < 0.001) and blood pressure (OR: 2.59 (1.75-3.85), p < 0.001), symptoms such as blood in sputum (OR: 1.69 (1.32-2.16), p < 0.001), shortness of breath (OR: 1.43 (1.19-1.72), p < 0.001) and weight loss (OR: 1.59 (1.33-1.89), p < 0.001). The cough was the most often reported symptom overall. There were gender differences in symptoms that prompted care-seeking: Males were more likely to seek care for weight loss (OR: 1.78 (1.42-2.23), p<0.001), blood in the sputum (OR: 1.69 (1.25-2.28), p<0.001), shortness of breath (OR: 1.49 (1.18-1.88), p<0.001) and fever (OR: 1.32 (1.05-1.65), p = 0.018). Females were more likely to seek care for blood in sputum (OR: 1.68 (1.10-2.58), p = 0.018) and shortness of breath (OR = 1.35, (1.01-1.82), p = 0.048). The cough did not feature as a significant symptom that prompted care-seeking.

CONCLUSION

Delayed healthcare-seeking behaviour among those with symptoms presumptive of TB in the tribal population is a major concern. Findings point to differences across gender about symptoms that prompt care-seeking in this population. Gender-sensitive interventions with health system strengthening are urgently needed to facilitate early diagnosis and treatment among this population.

Understanding Nonadherence to Tuberculosis Medications in India Using Urine Drug Metabolite Testing: A Cohort Study

BACKGROUND

Poor adherence to tuberculosis (TB) treatment is associated with disease recurrence and death. Little research has been conducted in India to understand TB medication nonadherence.

METHODS

We enrolled adult drug-susceptible TB patients, approximately half of whom were people with human immunodeficiency virus (PWH), in Chennai, Vellore, and Mumbai. We conducted a single unannounced home visit to administer a survey assessing reasons for nonadherence and collect a urine sample that was tested for isoniazid content. We described patient-reported reasons for nonadherence and identified factors associated with nonadherence (ie, negative urine test) using multivariable logistic regression. We also assessed the association between nonadherence and treatment outcomes.

RESULTS

Of 650 participants in the cohort, 77 (11.8%) had a negative urine test. Nonadherence was independently associated with daily wage labor (adjusted odds ratio [aOR], 2.7; confidence interval [CI], 1.1-6.5; P = .03), the late continuation treatment phase (aOR, 2.0; CI, 1.1-3.9; P = .03), smear-positive pulmonary disease (aOR, 2.1; CI, 1.1-3.9; P = .03), alcohol use (aOR, 2.5; CI, 1.2-5.2; P = .01), and spending ≥30 minutes collecting medication refills (aOR, 6.6; CI, 1.5-29.5; P = .01). People with HIV reported greater barriers to collecting medications than non-PWH. Among 167 patients reporting missing doses, reported reasons included traveling from home, forgetting, feeling depressed, and running out of pills. The odds of unfavorable treatment outcomes were 4.0 (CI, 2.1-7.6) times higher among patients with nonadherence (P < .0001).

CONCLUSION

Addressing structural and psychosocial barriers will be critical to improve TB treatment adherence in India. Urine isoniazid testing may help identify nonadherent patients to facilitate early intervention during treatment.

Evaluation of the Accuracy of 99DOTS, a Novel Cellphone-based Strategy for Monitoring Adherence to Tuberculosis Medications: Comparison of DigitalAdherence Data With Urine Isoniazid Testing

99DOTS is a cellphone-based strategy for monitoring tuberculosis medication adherence. In a sample of 597 Indian patients with tuberculosis, we compared 99DOTS' adherence assessments against results of urine isoniazid tests collected during unannounced home visits. 99DOTS had suboptimal accuracy for measuring adherence, partly due to poor patient engagement with 99DOTS.

Geographic and behavioral differences associated with sexually transmitted infection prevalence among Indian men who have sex with men in Chennai and Mumbai

India has one of the largest numbers of men who have sex with men (MSM) globally; however, geographic data on sexually transmitted infection (STI) prevalence and associations with sexual behavior are limited. Six-hundred and eight MSM in Chennai and Mumbai underwent screening for a behavioral trial and were assessed for bacterial STIs (syphilis, chlamydia, gonorrhea), HIV, and past-month self-reported condomless anal sex (CAS). Mumbai (37.8%) had a greater prevalence of any STI than Chennai (27.6%) (prevalence ratio [PR] = 1.37, 95% CI: 1.09, 1.73). This pattern also emerged for gonorrhea and chlamydia separately but not syphilis. Conversely, Mumbai MSM reported lower rates of CAS (mean = 2.2) compared to Chennai MSM (mean = 14.0) (mean difference = -11.8, 95% CI: -14.6, -9.1). The interaction of city by CAS on any STI prevalence (PR = 2.09, 95% CI: 1.45, 3.01, p < .0001) revealed that in Chennai, higher rates of CAS were not associated with STI prevalence, but in Mumbai they were (PR = 2.49, 95% CI: 1.65, 3.76, p < .0001). The higher prevalence of bacterial STIs but lower frequency of CAS in Mumbai (versus Chennai), along with the significant interaction of CAS with city on STI rates, suggests that there are either differences in disease burden or differences by city with respect to self-reported assessment of CAS. Regardless, the high prevalence rates of untreated STIs and condomless sex among MSM suggest the need for additional prevention intervention efforts for MSM in urban India.

Explaining Differences in the Acceptability of 99DOTS, a Cell Phone-Based Strategy for Monitoring Adherence to Tuberculosis Medications: Qualitative Study of Patients and Health Care Providers

Background

99DOTS is a cell phone–based strategy for monitoring tuberculosis (TB) medication adherence that has been rolled out to more than 150,000 patients in India’s public health sector. A considerable proportion of patients stop using 99DOTS during therapy.

Objective

This study aims to understand reasons for variability in the acceptance and use of 99DOTS by TB patients and health care providers (HCPs).

Methods

We conducted qualitative interviews with individuals taking TB therapy in the government program in Chennai and Vellore (HIV-coinfected patients) and Mumbai (HIV-uninfected patients) across intensive and continuation treatment phases. We conducted interviews with HCPs who provide TB care, all of whom were involved in implementing 99DOTS. Interviews were transcribed, coded using a deductive approach, and analyzed with Dedoose 8.0.35 software (SocioCultural Research Consultants, LLC). The findings of the study were interpreted using the unified theory of acceptance and use of technology, which highlights 4 constructs associated with technology acceptance: performance expectancy, effort expectancy, social influences, and facilitating conditions.

Results

We conducted 62 interviews with patients with TB, of whom 30 (48%) were HIV coinfected, and 31 interviews with HCPs. Acceptance of 99DOTS by patients was variable. Greater patient acceptance was related to perceptions of improved patient-HCP relationships from increased phone communication, TB pill-taking habit formation due to SMS text messaging reminders, and reduced need to visit health facilities (performance expectancy); improved family involvement in TB care (social influences); and from 99DOTS leading HCPs to engage positively in patients’ care through increased outreach (facilitating conditions). Lower patient acceptance was related to perceptions of reduced face-to-face contact with HCPs (performance expectancy); problems with cell phone access, literacy, cellular signal, or technology fatigue (effort expectancy); high TB- and HIV-related stigma within the family (social influences); and poor counseling in 99DOTS by HCPs or perceptions that HCPs were not acting upon adherence data (facilitating conditions). Acceptance of 99DOTS by HCPs was generally high and related to perceptions that the 99DOTS adherence dashboard and patient-related SMS text messaging alerts improve quality of care, the efficiency of care, and the patient-HCP relationship (performance expectancy); that the dashboard is easy to use (effort expectancy); and that 99DOTS leads to better coordination among HCPs (social influences). However, HCPs described suboptimal facilitating conditions, including inadequate training of HCPs in 99DOTS, unequal changes in workload, and shortages of 99DOTS medication envelopes.

Conclusions

In India’s government TB program, 99DOTS had high acceptance by HCPs but variable acceptance by patients. Although some factors contributing to suboptimal patient acceptance are modifiable, other factors such as TB- and HIV-related stigma and poor cell phone accessibility, cellular signal, and literacy are more difficult to address. Screening for these barriers may facilitate targeting of 99DOTS to patients more likely to use this technology.

Understanding pretreatment loss to follow-up of tuberculosis patients: an explanatory qualitative study in Chennai, India

Introduction

Pretreatment loss to follow-up (PTLFU)-dropout of patients after diagnosis but before treatment registration-is a major gap in tuberculosis (TB) care in India and globally. Patient and healthcare worker (HCW) perspectives are critical for developing interventions to reduce PTLFU.

Methods

We tracked smear-positive TB patients diagnosed via sputum microscopy from 22 diagnostic centres in Chennai, one of India's largest cities. Patients who did not start therapy within 14 days, or who died or were lost to follow-up before official treatment registration, were classified as PTLFU cases. We conducted qualitative interviews with trackable patients, or family members of patients who had died. We conducted focus group discussions (FGDs) with HCWs involved in TB care. Interview and FGD transcripts were coded and analysed with Dedoose software to identify key themes. We created categories into which themes clustered and identified relationships among thematic categories to develop an explanatory model for PTLFU.

Results

We conducted six FGDs comprising 53 HCWs and 33 individual patient or family member interviews. Themes clustered into five categories. Examining relationships among categories revealed two pathways leading to PTLFU as part of an explanatory model. In the first pathway, administrative and organisational health system barriers-including the complexity of navigating the system, healthcare worker absenteeism and infrastructure failures-resulted in patients feeling frustration or resignation, leading to disengagement from care. In turn, HCWs faced work constraints that contributed to many of these health system barriers for patients. In the second pathway, negative HCW attitudes and behaviours contributed to patients distrusting the health system, resulting in refusal of care.

Conclusion

Health system barriers contribute to PTLFU directly and by amplifying patient-related challenges to engaging in care. Interventions should focus on removing administrative hurdles patients face in the health system, improving quality of the HCW-patient interaction and alleviating constraints preventing HCWs from providing patient-centred care.

A computational solution to improve biomarker reproducibility during long-term projects

Biomarkers are fundamental to basic and clinical research outcomes by reporting host responses and providing insight into disease pathophysiology. Measuring biomarkers with research-use ELISA kits is universal, yet lack of kit standardization and unexpected lot-to-lot variability presents analytic challenges for long-term projects. During an ongoing two-year project measuring plasma biomarkers in cancer patients, control concentrations for one biomarker (PF) decreased significantly after changes in ELISA kit lots. A comprehensive operations review pointed to standard curve shifts with the new kits, an analytic variable that jeopardized data already collected on hundreds of patient samples. After excluding other reasonable contributors to data variability, a computational solution was developed to provide a uniform platform for data analysis across multiple ELISA kit lots. The solution (ELISAtools) was developed within open-access R software in which variability between kits is treated as a batch effect. A defined best-fit Reference standard curve is modelled, a unique Shift factor “S” is calculated for every standard curve and data adjusted accordingly. The averaged S factors for PF ELISA kit lots #1–5 ranged from -0.086 to 0.735, and reduced control inter-assay variability from 62.4% to <9%, within quality control limits. S factors calculated for four other biomarkers provided a quantitative metric to monitor ELISAs over the 10 month study period for quality control purposes. Reproducible biomarker measurements are essential, particularly for long-term projects with valuable patient samples. Use of research-use ELISA kits is ubiquitous and judicious use of this computational solution maximizes biomarker reproducibility.

Digital adherence technologies for the management of tuberculosis therapy: mapping the landscape and research priorities

Poor medication adherence may increase rates of loss to follow-up, disease relapse and drug resistance for individuals with active tuberculosis (TB). While TB programmes have historically used directly observed therapy (DOT) to address adherence, concerns have been raised about the patient burden, ethical limitations, effectiveness in improving treatment outcomes and long-term feasibility of DOT for health systems. Digital adherence technologies (DATs)-which include feature phone-based and smartphone-based technologies, digital pillboxes and ingestible sensors-may facilitate more patient-centric approaches for monitoring adherence, though available data are limited. Depending on the specific technology, DATs may help to remind patients to take their medications, facilitate digital observation of pill-taking, compile dosing histories and triage patients based on their level of adherence, which can facilitate provision of individualised care by TB programmes to patients with varied levels of risk. Research is needed to understand whether DATs are acceptable to patients and healthcare providers, accurate for measuring adherence, effective in improving treatment outcomes and impactful in improving health system efficiency. In this article, we describe the landscape of DATs that are being used in research or clinical practice by TB programmes and highlight priorities for research.

Pretreatment loss to follow-up of tuberculosis patients in Chennai, India: a cohort study with implications for health systems strengthening

Background

Pretreatment loss to follow-up (PTLFU) is a barrier to tuberculosis (TB) control in India’s Revised National TB Control Programme (RNTCP). PTLFU studies have not been conducted in India’s mega-cities, where patient mobility may complicate linkage to care.

Methods

We collected data from patient registries for May 2015 from 22 RNTCP designated microscopy centers (DMCs) in Chennai and audited addresses and phone numbers for patients evaluated for suspected TB to understand how missing contact information may contribute to PTLFU. From November 2015 to June 2016, we audited one month of records from each of these 22 DMCs and tracked newly diagnosed smear-positive patients using RNTCP records, phone calls, and home visits. We defined PTLFU cases as including: (1) patients who did not start TB therapy within 14 days and (2) patients who started TB therapy but were lost to follow-up or died before official RNTCP registration. We used multivariate logistic regression to identify factors associated with PTLFU.

Results

In the audit of May 2015 DMC registries, out of 3696 patients evaluated for TB, 1273 (34.4%) had addresses and phone numbers that were illegible or missing. Out of 344 smear-positive patients tracked from November 2015 to June 2016, 40 (11.6%) did not start TB therapy within 14 days and 36 (10.5%) started therapy but were lost to follow-up or died before official RNTCP registration, for an overall PTLFU rate of 22.1% (95%CI: 17.8%—26.4%). Of all PTLFU patients, 55 (72.4%) were lost to follow-up and 21 (27.6%) died before starting treatment or before RNTCP registration. In the regression analysis, age > 50 years (OR 2.9, 95%CI 1.4—6.5), history of prior TB (OR 3.9, 95%CI 2.2—7.1), evaluation at a high patient volume DMC (OR 3.2, 95% CI 1.7—6.3), and absence of legible patient contact information (OR 4.5, 95%CI 1.3—15.1) were significantly associated with PTLFU.

Conclusions

In an Indian mega-city, we found a high PTLFU rate, especially in patients with a prior TB history, who are at greater risk for having drug-resistance. Enhancing quality of care and health system transparency is critical for improving linkage of newly diagnosed patients to TB care in urban India.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3039-3) contains supplementary material, which is available to authorized users.

Tuberculosis patients in an Indian mega-city: Where do they live and where are they diagnosed?

Objective

Tuberculosis (TB) is a major source of mortality in urban India, with many structural challenges to optimal care delivery. In the government TB program in Chennai, India’s fourth most populous city, there is a 49% gap between the official number of smear-positive TB patients diagnosed and the official number registered in TB treatment within the city in 2014. We hypothesize that this “urban registration gap” is partly due to rural patients temporarily visiting the city for diagnostic evaluation.

Methods

We collected data for one month (May 2015) from 22 government designated microscopy centers (DMCs) in Chennai where 90% of smear-positive TB patients are diagnosed and coded patient addresses by location. We also analyzed the distribution of chest symptomatics (i.e., patients screened for TB because of pulmonary symptoms) and diagnosed smear-positive TB patients for all of Chennai’s 54 DMCs in 2014.

Results

At 22 DMCs in May 2015, 565 of 3,543 (15.9%) chest symptomatics and 71 of 412 (17.2%) diagnosed smear-positive patients had an address outside of Chennai. At the city’s four high patient volume DMCs, 54 of 270 (20.0%) smear-positive patients lived out-of-city. At one of these high-volume DMCs, 31 of 59 (52.5%) smear-positive patients lived out-of-city. Out of 6,135 smear-positive patients diagnosed in Chennai in 2014, 3,498 (57%) were diagnosed at the four high-volume DMCs. The 32 DMCs with the lowest patient volume diagnosed 10% of all smear-positive patients.

Conclusions

TB case detection in Chennai is centralized, with four high-volume DMCs making most diagnoses. One-sixth of patients are from outside the city, most of whom get evaluated at these high-volume DMCs. This calls for better coordination between high-volume city DMCs and rural TB units where many patients may take TB treatment. Patient mobility only partly explains Chennai’s urban registration gap, suggesting that pretreatment loss to follow-up of patients who live within the city may also be a major problem.

Transactional sex and the challenges to safer sexual behaviors: a study among male sex workers in Chennai, India

Male sex workers (MSW) are a significant but invisible population in India who are at risk for HIV/sexually transmitted infections (STIs). Few studies from India have documented HIV risk factors and motivations for sex work in this population. Between 2013 and 2014, a community-based convenience sample of 100 MSW in Chennai (south India) completed a baseline risk assessment as part of a behavioral intervention. Participants were ≥18 years, and reported current sex work. We report medians and proportions, and Wilcoxon-Mann-Whitney and chi-square tests are used to examine differences between sex work and sexual behavior measures by income source. Participants were engaged in sex work for 5.0 years (IQR = 2.3-10.0), and earned 3000 (IQR = 2000-8000) Rupees (<50 USD) per month from sex work. Sixty-four percent reported ever testing for HIV and 20.2% for any STI. The most common reasons for starting sex work were money (83.0%) and pleasure (56.0%). Compared to participants with an additional source of income, those whose only source of income was sex work reported more male clients in the past month (10.0 vs. 6.0, p = .017), as well as more condomless anal sex acts with male clients (8.0 vs. 5.0, p = .008). Nearly 70.0% were offered more money not to use a condom during sex with a client, and 74.2% reported accepting more money not to use a condom. Three-quarters reported having experienced difficulty using condoms with clients. MSW in India engage in high levels of sexual risk for HIV/STIs. Money appears to be a driving factor for engaging in sex work and condomless sex with clients. HIV prevention interventions with MSW should focus on facilitating skills that will support their ability to negotiate sexual safety in the context of monetary disincentives.

Pulmonary tuberculosis among tribals in India: A systematic review & meta-analysis

Background & objectives:

There has been limited investigation on the prevalence of tuberculosis (TB) in tribal communities in India, a vulnerable section of Indian society. The lack of a population-based estimate prompted us to conduct a meta-analysis of existing studies to provide a single, population-based estimate of the TB prevalence for tribals.

Methods:

Literature search was conducted in PubMed using the keywords - “tuberculosis”, “tribals”, “India”, “prevalence”, and “survey”. References cited in the articles retrieved were also reviewed, and those found relevant were selected. TB prevalence rates estimated by the studies were used for our calculation of a pooled-estimate.

Results:

The pooled estimate, based on the random effects model, was 703 per 100,000 population with a 95 % CI of 386-1011. The associated heterogeneity measures in terms of Cochran's Q was significant (P=0 0.08 <0.1) and I² was moderate at 48 per cent.

Interpretation & conclusions:

The meta-analysis demonstrated a large variability in pulmonary TB prevalence estimates among the different studies with poor representation of the various tribal groups. The moderate level of heterogeneity found across the studies suggests that the pooled-estimate needs to be treated with caution. Our findings also highlight the need to assess the pulmonary TB burden in India.

Prevalence of chest symptoms amongst brick kiln migrant workers and care seeking behaviour: a study from South India

BACKGROUND

Early detection and treatment of tuberculosis (TB) have been key principles of TB control. However, this can be a challenge with 'hard to reach' populations such as migrants. Brick kiln workers are one such group of migrants who are exposed to smoke, heat and dust from brick kilns which are one of the major causes of respiratory illnesses.

METHODOLOGY

A cross-sectional community based study was carried out in Thiruvallur, Tamil Nadu, South India, from August 2011 to June 2012. A total of 4002 individuals from 55 brick kiln chambers were interviewed to determine the prevalence of chest symptoms and care seeking behaviour patterns.

RESULTS

Three hundred and seventy-seven (9.4%) chest symptomatics were identified. The most significant variables associated with chest symptoms were illiteracy, alcohol abuse and heavy smoking. Of the chest symptomatics identified, 50.4% took action to get relief from their symptoms. The duration of over 6-month stay in the chamber was significantly associated with taking action (OR, 5.5, 95% CI: 2.3, 13.3).

CONCLUSIONS

The TB control programme needs to further explore how to extend its services to such 'hard to reach' groups. Active case finding to ensure early diagnosis and treatment initiation amongst such groups needs consideration.

Alcohol use disorders (AUD) among tuberculosis patients: a study from Chennai, South India

BACKGROUND

Alcohol Use Disorders (AUDs) among tuberculosis (TB) patients are associated with nonadherence and poor treatment outcomes. Studies from Tuberculosis Research Centre (TRC), Chennai have reported that alcoholism has been one of the major reasons for default and mortality in under the DOTS programme in South India. Hence, it is planned to conduct a study to estimate prevalence of alcohol use and AUDs among TB patients attending the corporation health centres in Chennai, India.

METHODOLOGY

This is a cross-sectional cohort study covering 10 corporation zones at Chennai and it included situational assessment followed by screening of TB patients by a WHO developed Alcohol Use Disorders Identification Test AUDIT scale. Four zones were randomly selected and all TB patients treated during July to September 2009 were screened with AUDIT scale for alcohol consumption.

RESULTS

Out of 490 patients, 66% were males, 66% were 35 years and above, 57% were married, 58% were from the low monthly income group of 8. Age (>35 years), education (less educated), income (

CONCLUSIONS

AUD among TB patients needs to be addressed urgently and the findings suggest the importance of integrating alcohol treatment into TB care.

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Key Words Collapse

MESH Headings

• Adult
• Alcohol Drinking/epidemiology
• Alcohol-Related Disorders/complications
• Alcohol-Related Disorders/epidemiology
• Alcohol-Related Disorders/therapy
• Demography
• Female
• Humans
• India/epidemiology
• Male
• Mass Screening
• Treatment Outcome
• Tuberculosis/complications
• Tuberculosis/diagnosis
• Tuberculosis/epidemiology
• Tuberculosis/therapy

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Grants Collapse

Affiliation(s)

Mohanarani Suhadev Tuberculosis Research Centre, Chetput, Chennai, Tamilnadu, India.
Beena E Thomas
M Raja Sakthivel
P Murugesan
V Chandrasekaran
Niruparani Charles
R Durga
M Auxilia
Trini A Mathew
Fraser Wares

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Nutritional supplementation in HIV-infected individuals in South India: a prospective interventional study

BACKGROUND

Malnutrition in human immunodeficiency virus (HIV)-infected individuals is associated with faster disease progression, higher mortality rates, and suboptimal response to antiretroviral therapy (ART).

METHODS

We conducted a prospective interventional study to evaluate the effects of an oral macronutrient supplement among HIV-infected adults in South India. Patients attending Tuberculosis Research Centre clinics from June 2005 through December 2007 had baseline nutritional assessment and laboratory investigations performed. Patients at 1 center received nutritional counseling and standard care, whereas patients at 2 centers additionally received a macronutrient providing 400 cal and 15 g of protein daily. Study outcomes were changes in anthropometry, body composition, blood chemistry, and immune status at 6 months.

RESULTS

In total, 636 ART-naive patients were enrolled in the study; 361 completed 6 months of follow-up (282 received supplements and 79 received standard care). Mean age +/- standard deviation (SD) was 31 +/- 7 years, mean weight +/- SD was 50 +/- 10 kg, and 42% were male. Significant increases in body weight, body mass index, midarm circumference, fat-free mass, and body cell mass were observed in the supplement group but not in the control group at 6 months; gains were greater in patients with CD4 cell counts <200 cells/microL. No changes were observed in lipid levels, whereas the CD4 cell count decreased in the control group. However, after adjusting for baseline differences, these changes were not statistically significantly different between the groups.

CONCLUSIONS

Macronutrient supplementation did not result in significantly increased weight gain compared with standard care (including nutritional counseling) among patients with moderately advanced HIV disease. The effect of supplementation on specific subsets of patients and on preserving immune function needs further research.

Depressive symptoms and human immunodeficiency virus risk behavior among men who have sex with men in Chennai, India

Men who have sex with men (MSM) in India are a hidden population, facing unique environmental stressors and cultural pressures that place them at risk for depression. Depression may affect HIV risk behavior in MSM, and may affect the degree to which MSM may benefit from HIV prevention interventions. Depression in MSM in India, however, has largely been understudied. Two hundred ten MSM in Chennai completed an interviewer-administered behavioral assessment battery, which included the 20-item Center for Epidemiologic Studies Depression Scale (CES-D), demographics, sexual risk and identity, and other psychosocial variables. Over half (55%) of the sample exceeded the cutoff (CES-D >or= 16) to screen in for clinically significant depressive symptoms; this was associated with having had unprotected anal sex (OR = 1.97; 95% CI: 1.01-3.87) and higher number of male partners (OR = 1.04; 95% CI: 1.01-1.07). Statistically significant bivariate predictors of meeting the screen in for depressive symptoms included sexual identity (Kothi > Panthi; OR = 4.90; 95% CI: 2.30-10.54), not being married (OR = 3.40; 95% CI: 1.72-6.81), not having a child (OR = 4.40; 95% CI: 2.07-9.39), family not knowing about one's MSM identity (OR = 2.30; 95% CI: 1.18-4.90), having been paid for sex (OR = 5.10; p 95% CI: 2.87-9.47), and perceiving that one is at risk for acquiring HIV (OR = 1.10; 95% CI: 1.02-1.17; continuous). In a multivariable logistic-regression model, unique predictors of screening in for depressive symptoms included not being married (AOR = 3.10; 95% CI: 1.23-7.65), having been paid for sex (AOR = 3.80; 95% CI: 1.87-7.99) and the perception of increased risk for HIV (AOR = 1.10; 95% CI: 1.03-1.21; continuous); unprotected anal sex in the 3 months prior to study enrollment approached statistical significance (AOR = 2.00; 95% CI: 0.91-4.48). Depression among MSM in Chennai is of concern and should be considered while developing HIV prevention interventions with this population. MSM who are not married, sex workers, and those who perceive they are at risk for acquiring HIV may be of higher risk for symptoms of depression.

Morphologic and body composition changes are different in men and women on generic combination antiretroviral therapy--an observational study

BACKGROUND

Increasingly effective therapies for HIV infection, combination antiretroviral therapy, are now widely available in developing countries. A range of metabolic complications presenting as abnormalities of body-fat mass distribution in association with dyslipidemia and glucose homeostasis dysregulation, have been recognized as important toxicities in patients treated with these drugs. With increasing use of antiretroviral therapy in India, we examined the association between gender and body shape and composition, one year after initiating combination antiretroviral therapy and attempted to identify simple clinical markers to detect and monitor these changes.

METHODS

Patients on combination antiretroviral therapy (2 NRTIs + 1 NNRTI), attending a HIV clinic between July 2005 and December 2006 had anthropometry clinical examination and bioelectric impedance analysis (BIA) performed along with blood tests at baseline and after 1 year.

RESULTS

Of the 34 patients on combination antiretroviral therapy, 5 males and 12 females had noticeable changes in their body shape. Significant decrease in triceps skin fold thickness, an increase in waist circumference and waist: hip ratio was observed in females. BIA did not show any change in total body fat in either sex.

CONCLUSIONS

Since the presence and severity of fat redistribution could affect adherence as well as the success of antiretroviral therapy, close monitoring is required to detect and prevent this complication early.

Perceptions of tuberculosis patients on provider-initiated HIV testing and counseling--a study from south India

Background

The acceptability and feasibility of provider-initiated HIV testing and counseling (PITC) in many settings across Asia with concentrated HIV epidemics is not known. A pilot study of the PITC policy undertaken within the public health care systems in two districts in India offered the opportunity to understand patient's perspectives on the process of referral for HIV testing and linking to HIV treatment and care.

Methods

We conducted a cross-sectional study of randomly selected TB patients registered by the TB control program between July and November 2007 in two districts in south India. Trained interviewers met patients shortly after TB diagnosis and administered a structured questionnaire. Patients were assessed regarding their experience with HIV status assessment, referral for counseling and testing, and for HIV-infected patients the counseling itself and subsequent referral for HIV treatment and care.

Results

Of the 568 interviewed TB patients, 455 (80%) reported being referred for HIV testing after they presented to the health facility for investigations or treatment for TB. Over half the respondents reported having to travel long distances and incurred financial difficulties in reaching the Integrated Counselling and Testing Centre (ICTC) and two-thirds had to make more than two visits. Only 48% reported having been counseled before the test. Of the 110 HIV-infected patients interviewed, (including 43 with previously-known positive HIV status and 67 detected by PITC), 89 (81%) reported being referred for anti-retroviral treatment (ART); 82 patients reached the ART centre but only 44 had been initiated on ART.

Conclusions

This study provides the first evidence from India that routine, provider-initiated voluntary HIV testing of TB patients is acceptable, feasible and can be achieved with very high efficiency under programmatic conditions. While PITC is useful in identifying new HIV-infected patients so that they can be successfully linked to ART, the convenience and proximity of testing centres, quality of HIV counseling, and efficiency of ART services need attention.

Gender differences in sexual behaviour among people living with HIV in Chennai, India

BACKGROUND & OBJECTIVE

Risky sexual behaviour is usually the focus of HIV prevention programmes and little attention has been given to sexual behaviour patterns among HIV positive individuals. In order to ensure that people with HIV receive high quality sexual and mental health services, providers must have a comprehensive understanding of the issues and challenges faced by men and women with HIV. This study was conducted to gain insight into the gender differences in sexual behaviour patterns among HIV seropositive men and women in south India.

METHODS

This descriptive cross-sectional study on a cohort of 203 seropositive patients (102 women and 101 men) attending outpatient clinics in the Tuberculosis Research Centre and the STD clinic of the Government General Hospital, Chennai, India. A semi-structured interview schedule was administered to collect information from the respondents.

RESULTS

Fifty three per cent of the women were discontented with the sexual relationship with their spouse as compared to 23 per cent of the men (P<0.001). Thirty two of the 54 women who refused sex said that their spouses reacted violently to their refusal. More men than women reported to having extramarital relationships most often with a commercial sex worker or a friend, without condoms and usually under the influence of alcohol.

INTERPRETATION & CONCLUSION

There are gender differences in sexual behaviour patterns among men and women. Understanding these differences is important to plan gender based intervention strategies in order to ensure that people living with HIV have a better quality of life, addressing their sexual concerns both within and outside of marriage. The findings will also help in advocacy and prevention programmes aimed at HIV/AIDS control.

Gender and socio-cultural determinants of TB-related stigma in Bangladesh, India, Malawi and Colombia

SETTING

Tuberculosis (TB) control programmes in Bangladesh, India, Malawi and Colombia.

OBJECTIVE

Assess indicators of TB-related stigma and socio-cultural and gender-related features of illness associated with stigma.

DESIGN

Semi-structured Explanatory Model Interview Catalogue (EMIC) interviews were administered to 100 or more patients at each site, assessing categories of distress, perceived causes and help seeking. Indicators of self-perceived stigma were analysed individually and in a validated index, which was compared across sites and between men and women at each site. Cultural epidemiological explanatory variables for stigma and interactions with female sex were analysed at each site. Qualitative illness narratives were examined to explain the role and context of explanatory variables.

RESULTS

The overall stigma index was highest in India, lowest in Malawi and greater for women in Bangladesh. In India and Malawi, women were more likely to be concerned about impact on marital prospects. Associations with HIV/AIDS were linked to TB stigma in Malawi, where sexual contact as a perceived cause was more associated with stigma for men and less for women.

CONCLUSION

Stigma both influences and indicates the effectiveness of TB control. Cultural epidemiological methods clarify cross-cutting and local features of stigma and gender for TB control.

Mapping peptide hormone-receptor interactions using a disulfide-trapping approach

Efforts to elucidate the nature of the bimolecular interaction of parathyroid hormone (PTH) with its cognate receptor, the PTH receptor type 1 (PTHR1), have relied heavily on benzoylphenylalanine- (Bpa-) based photoaffinity cross-linking. However, given the flexibility, size, and shape of Bpa, the resolution at the PTH-PTHR1 interface appears to be reaching the limit of this technique. Here we employ a disulfide-trapping approach developed by others primarily for use in screening compound libraries to identify novel ligands. In this method, cysteine substitutions are introduced into a specific site within the ligand and a region in the receptor predicted to interact with each other. Upon ligand binding, if these cysteines are in close proximity, they form a disulfide bond. Since the geometry governing disulfide bond formation is more constrained than Bpa cross-linking, this novel approach can be employed to generate a more refined molecular model of the PTH-PTHR1 complex. Using a PTH analogue containing a cysteine at position 1, we probed 24 sites and identified 4 in PTHR1 to which cross-linking occurred. Importantly, previous photoaffinity cross-linking studies using a PTH analogue with Bpa at position 1 only identified a single interaction site. The new sites identified by the disulfide-trapping procedure were used as constraints in molecular dynamics simulations to generate an updated model of the PTH-PTHR1 complex. Mapping by disulfide trapping extends and complements photoaffinity cross-linking. It is applicable to other peptide-receptor interfaces and should yield insights about yet unknown sites of ligand-receptor interactions, allowing for generation of more refined models.

Conformational changes in the parathyroid hormone receptor associated with activation by agonist

Binding of hormones to their cognate G protein-coupled receptors (GPCRs) induces conformational shifts within the receptor based on evidence from a few hormone-receptor systems. Employing an engineered disulfide bond formation strategy and guided by a previously established model of the PTH-PTH receptor (PTHR)1 bimolecular complex, we set out to document and characterize the nature of agonist-induced changes in this family B GPCR. A mutant PTHR1 was generated which incorporates a Factor Xa cleavage site in the third intracellular loop. Treatment with Factor Xa fragments the receptor. However, if a new disulfide bond was formed before exposure to the enzyme, the fragments remain held together. A set of double cysteine-containing mutants were designed to probe the internal relative movements of transmembrane (TM) helices 2 and TM7. PTH enhanced formation of disulfide bonds in the K240C/F447C and A242C/F447C mutants. For the F238C/F447C mutant, a disulfide bond is formed in the basal state, but is disrupted by interaction with PTH. For the D241C/F447C PTHR1 construct, no disulfide bond formation was observed in either the basal or hormone-bound state. These findings demonstrate that the conformation of PTHR1 is altered from the basal state when PTH is bound. Novel information regarding spatial proximities between TM2 and TM7 of PTHR1 and the nature of relative movements between the two transmembrane regions was revealed. The data confirm and extend the experimentally derived model of the PTH-PTHR1 complex and provide insights at a new level of detail into the early events in PTHR1 activation by PTH.

Perceptions of gender and tuberculosis in a south Indian urban community

BACKGROUND

The Revised National Tuberculosis Control Programme (RNTCP) in India advocating Directly Observed Treatment-Short course (DOTS) detects nearly three times more male than female TB patients. The reasons for this difference are unclear. An understanding of the community's health beliefs, perceptions on the disease and behaviour towards TB patients may throw some light on this issue.

MATERIAL AND METHODS

A qualitative study using focus group discussions was conducted among men and women of younger and older age groups from lower income neighbourhoods. The information obtained was grouped into themes which included, understanding of TB, vulnerability, access to health care and social responses. Gender differences in community perceptions on TB seem to be critical in issues related to marriage.

RESULTS

The stigma of TB is more visible in women than men when it comes to marriage. Men and children were perceived to get preferential attention by their families during illness. While the younger age group, irrespective of gender, accessed care from private providers, the older group preferred a government facility. Awareness of TB was acceptable but it seemed more associated as a respiratory disease and the common symptom associated with TB was cough.

CONCLUSION

This study highlights the need for gender specific intervention strategies to enhance better access of TB services.

Feasibility of routine HIV testing among TB patients through a voluntary counselling and testing centre

BACKGROUND

Despite the synergy between the human immunodeficiency virus (HIV) and tuberculosis (TB) epidemics, the public health responses have largely been separate. Detection of HIV among TB patients is crucial to the holistic management of HIV-TB co-infected patients.

OBJECTIVE

To assess the feasibility of screening all TB patients for HIV through referral to a voluntary counselling and testing centre.

DESIGN

This cross-sectional study of 4802 newly diagnosed TB patients between July 2005 and June 2006 was performed in Tamilnadu, India, at six sites.

RESULTS

Of 4802 patients invited, 69% were willing to participate in the test. The most significant variables that influenced willingness were sex, age and place of residence (P < 0.01). The other significant variables that influenced willingness to participate were higher education, being employed and being married (P < 0.05). The main reasons for refusal of HIV screening among the patients were 'no risk behaviour' (30%), followed by 'too old' (23%) and for reasons of privacy (12%).

CONCLUSIONS

The present study suggests that it is feasible to routinely test TB patients for HIV. However it is crucial for health providers to focus on an effective referral process keeping patient concerns in mind. Motivation strategies need to be sex-, age-, education- and residence-specific.

Cysteine at position 217 in the intracellular loop 1 plays a critical role in human PTH receptor type 1 membrane translocation and function

PTHR1 mutants lacking endogenous cysteines in transmembrane and intracellular domains were generated. Mutant receptors were tested for their biological activities and mRNA and cell surface expression levels. C217 in intracellular loop 1 was determined to play a critical role in cell surface translocation and function of the receptor.

INTRODUCTION

Elucidating the role of different domains of PTH receptor 1 (PTHR1) is essential for understanding the mechanism of ligand-receptor interactions. Here we present a study directed at determining the importance of cysteine residues present in the intracellular and transmembrane (TM) domains of the receptor.

MATERIALS AND METHODS

Mutant receptors were generated by site-directed mutagenesis. Biological activities were characterized by adenylyl cyclase and competition binding assays. RT-PCR, ELISA, and immunofluorescence microscopy were carried out to determine receptor mRNA and protein expression levels.

RESULTS

Mutations C460L and C462L in TM7, C568L in the C-terminal intracellular domain of the receptor, and removal of C397 in intracellular loop (ICL)3 by insertion of cleavage sites for Factor Xa did not affect binding affinity of PTH or agonist-induced adenylyl cyclase activity, although maximal responses (IC(max) and EC(max)) were decreased. However, mutations C217L in ICL1 or both C217L and C568L simultaneously resulted in a decrease in binding and loss of adenylyl cyclase activity. RT-PCR results showed that the observed changes in binding and activity were not caused by changes in mRNA expression. Next, we determined cell surface and total expression of the wildtype and mutant receptors by ELISA. We found that mutations of C460/C462 to L moderately decreased transfer of receptors to the cell surface. However, mutation of C217 to L in the ICL1 drastically reduced cell surface expression. Immunofluorescence and confocal microscopy studies confirmed reduced cell surface expression of receptors containing the C217L mutation. Similar results were obtained when replacing C217 and C460/C462 of the receptor with A instead of L.

CONCLUSIONS

Our studies indicate that the cysteine at position 217 in ICL1 plays a critical role in translocation to the cell surface and biological function of PTHR1.

How stigmatizing is Stigma in the life of people living with HIV: A study on HIV positive individuals from Chennai, South India

The nature and intensity of AIDS stigma are shaped by the social construction of the epidemic in different locales. Stigma therefore needs to be discussed in its cultural context. This clinic-based study aims at understanding stigma among 203 HIV positive individuals from Chennai, South India. The study throws light on the impact of stigma on the quality of life among these individuals. It also discusses the gender implications of stigma. This study brings out the findings that actual stigma experienced among those infected with HIV is much less (26%) as compared to the fear of being stigmatized or perceived stigma (97%). Internalizing of stigma was found to have a highly significant negative correlation with quality of life in the psychological domain and a significant negative correlation in the environmental domain. However individuals who did experience actual stigma seemed more determined to live and experience an above moderate quality of life. The implication of this study encourages HIV infected individuals to rise above stigma, avoid internalizing their stigmatized feelings and work toward a better quality of life. Health providers need to address these issues in their care for HIV infected individuals.

Methionine acts as a “magnet” in photoaffinity crosslinking experiments

Photoaffinity crosslinking has been utilized to probe the nature of the ligand-receptor interface for a number of G protein-coupled receptor systems. Often the photoreactive benzophenone moiety incorporated in the ligand is found to react with a methionine in the receptor. We introduced methionines one-at-a-time into the region 163-176 of the parathyroid hormone receptor, and find that crosslinking occurs to the side-chain of methionine over a range of 11 amino acids. We call this the "Magnet Effect" of methionine. Hence, crosslinking contact points can be significantly shifted by the presence of methionine in a receptor domain.

The Mid-Region of Parathyroid Hormone (1−34) Serves as a Functional Docking Domain in Receptor Activation

Elucidating the bimolecular interface between parathyroid hormone (PTH) and its cognate G protein-coupled receptor (PTHR1) should yield insights into the basis of molecular recognition and the mechanism of ligand-mediated intracellular signaling for a system that is critically important in regulating calcium levels in blood. We used photoaffinity scanning (PAS) to identify key ligand-receptor interactions for residues from the unstructured mid-region domain of PTH-(1-34). Four PTH analogues, containing a single photoreactive p-benzoylphenylalanine (Bpa) residue in position 11, 15, 18, or 21, were found to photo-cross-link within receptor regions [165-176], [183-189], [190-298], and [165-176], respectively. Addition of these mid-region contacts as constraints to our previously proposed model of the PTH-PTHR1 complex and extensive molecular simulation experiments enables substantial refinement of the model. Specifically, (1) the overall receptor-bound conformation of the hormone is not extended, but bent; (2) helix [169-176] of the N-terminal extracellular domain (N-ECD) of the receptor is redirected toward the heptahelical bundle; and (3) the hormone traverses between the top of transmembrane (TM) helices 1 and 2, rather than between TM-7 and TM-1. This significantly alters the model of both the receptor-bound tertiary structure of the hormone and the topological orientation of the C-terminus of the N-ECD in the hormone-receptor bimolecular complex. We propose that the mid-region of PTH-(1-34) has a role in fixing, by extensive contacts with the receptor, the entry of the N-terminal helix of the hormone into the heptahelical bundle between TM-1 and TM-2. This anchorage would orient the amino terminus into position to activate the receptor.

Immune reconstitution syndrome following initiation of antiretroviral therapy in a patient with HIV infection and multidrug-resistant tuberculosis

Paradoxical exacerbation of the signs and symptoms of tuberculosis may occur not only after antituberculosis therapy, but also soon after the initiation of a potent combination of antiretroviral drugs in human immunodeficiency virus (HIV) serpositive patients with tuberculosis. We report a case of immune reconstitution syndrome in response to antiretroviral therapy in a HIV-positive patient on antituberculosis therapy for multidrug-resistant tuberculosis.