Immunophenotype associated with high sustained antibody titers against enzyme replacement therapy in infantile-onset Pompe disease

Introduction

The efficacy of enzyme replacement therapy (ERT) with alglucosidase alfa for infantile-onset Pompe disease (IOPD) is limited in some patients due to the development of high and sustained antibody titers (HSAT; ≥12,800).

Methods

We carried out detailed immunophenotyping of IOPD patients (n=40), including analysis of circulating cell populations by flow cytometry and plasma cytokines by multiplex array, to determine whether patients with HSAT have unique immunological characteristics compared to those with low titers (LT; <12,800).

Results

Compared to patients with LT, patients who develop HSAT were skewed toward a type 2 immune profile, with an increased frequency of Th2 cells that was positively correlated with levels of Th2 (IL-4, IL-5, IL-13) and pro-inflammatory (IL-6, TNF-α, MIP-1α, MIP-1β) cytokines. B cells were increased in HSAT patients with a decreased fraction of unswitched memory B cells. Plasma GM-CSF concentrations were lower on average in HSAT patients, while CXCL11 was elevated. Finally, using principal components analysis, we derived an HSAT Signature Score that successfully stratified patients according to their antibody titers.

Discussion

The immune profiles revealed in this study not only identify potential biomarkers of patients that developed HSAT but also provide insights into the pathophysiology of HSAT that will ultimately lead to improved immunotherapy strategies.

Investigating potential immune mechanisms of trilaciclib administered prior to chemotherapy in patients with metastatic triple-negative breast cancer

PURPOSE

In a phase II trial in patients with metastatic triple-negative breast cancer (mTNBC; NCT02978716), administering trilaciclib prior to gemcitabine plus carboplatin (GCb) enhanced T-cell activation and improved overall survival versus GCb alone. The survival benefit was more pronounced in patients with higher immune-related gene expression. We assessed immune cell subsets and used molecular profiling to further elucidate effects on antitumor immunity.

METHODS

Patients with mTNBC and ≤ 2 prior chemotherapy regimens for locally recurrent TNBC or mTNBC were randomized 1:1:1 to GCb on days 1 and 8, trilaciclib prior to GCb on days 1 and 8, or trilaciclib alone on days 1 and 8, and prior to GCb on days 2 and 9. Gene expression, immune cell populations, and Tumor Inflammation Signature (TIS) scores were assessed in baseline tumor samples, with flow cytometric analysis and intracellular and surface cytokine staining used to assess immune cell populations and function.

RESULTS

After two cycles, the trilaciclib plus GCb group (n = 68) had fewer total T cells and significantly fewer CD8+ T cells and myeloid-derived suppressor cells compared with baseline, with enhanced T-cell effector function versus GCb alone. No significant differences were observed in patients who received GCb alone (n = 34). Of 58 patients in the trilaciclib plus GCb group with antitumor response data, 27 had an objective response. RNA sequencing revealed a trend toward higher baseline TIS scores among responders versus non‑responders.

CONCLUSION

The results suggest that administering trilaciclib prior to GCb may modulate the composition and response of immune cell subsets to TNBC.

Abstract 703: Transient G1 cell cycle arrest with trilaciclib enhances the generation of polyfunctional CD4+ and CD8+ T cells

When administered prior to chemotherapy, intravenous trilaciclib transiently arrests cyclin-dependent kinase 4/6-dependent cells in the G1 phase of the cell cycle, which has been shown to augment antitumor immunity. In an open-label, phase 2 trial in patients with metastatic triple-negative breast cancer (NCT02978716), administering trilaciclib prior to gemcitabine plus carboplatin improved overall survival, potentially through protection and direct activation of immune function. To determine the impact of trilaciclib on effector T-cell function, we conducted in vitro studies to assess the kinetics of cytotoxic function and generation of polyfunctional T cells.

Peripheral blood mononuclear cells (PBMCs) or naïve CD4+ and CD8+ T cells were purified from 6 healthy human donors and activated with CD2/3/28 beads. On days 0, 1, and 3 post activation, 100 nM trilaciclib was added to the cells. To visualize phenotypic and functional changes, T cells that had been activated for 3, 7, or 14 days with or without trilaciclib were restimulated with phorbol myristate acetate (PMA) and ionomycin. Dimension-reduction analysis of flow cytometric data was used to identify polyfunctional subpopulations of CD4+ and CD8+ T cells. T-cell clusters with polyfunctional profiles were identified based on the coproduction of IFNγ, TNFα, and IL-2 cytokines. Subsets of polyfunctional clusters were defined according to other immune phenotypic profiles, including T-cell exhaustion (PD-1 and LAG-3), degranulation (granzyme B), proliferation (Ki-67), and transcription factors (TOX, TCF-1, and T-bet).

For both CD4+ and CD8+ T cells, 3 polyfunctional subpopulations were identified based on differential expression of granzyme B, PD-1, and TOX. When CD4+ and CD8+ T cells were activated in the presence of trilaciclib and restimulated with PMA and ionomycin, there was an increase in the frequency of polyfunctional T-cell subsets producing granzyme B. This was compensated by a decrease in granzyme Blow polyfunctional cells, which was associated with increased PD-1high and TOXhigh expression. Clustering analysis of trilaciclib-treated PBMCs also revealed a reduction in proliferating CD8+ T cells with undetectable effector cytokine function based on a decrease in the frequency of CD8+ T cells expressing TOXhigh and Ki-67high.

Transient G1 cell cycle arrest in T cells may limit T-cell hyperactivation, which has been shown to induce immunopathological responses. The increased generation of polyfunctional CD8+ T cells is associated with enhanced effector T-cell responses and memory T-cell differentiation. In combination with previous data showing increased differentiation of naïve T cells into memory T cells upon exposure to trilaciclib, these data support a beneficial role for trilaciclib in enhancing antitumor T-cell responses.

Citation Format: Sarah Ahn, Subing Cao, Melissa A. Russo, John S. Yi. Transient G1 cell cycle arrest with trilaciclib enhances the generation of polyfunctional CD4+ and CD8+ T cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 703.

Abstract 6674: Single-dose trilaciclib monotherapy potentiates antitumor immunity in the neoadjuvant setting of triple-negative breast cancer by modulating the composition and effector function of peripheral immune cells

Intravenous administration of trilaciclib transiently arrests cyclin-dependent kinase 4/6-dependent cells in the G1 phase of the cell cycle during chemotherapy exposure. In an open-label, phase 2 study in patients with metastatic triple-negative breast cancer (TNBC; NCT02978716), administering trilaciclib prior to gemcitabine plus carboplatin improved overall survival and resulted in enriched T-cell diversity and decreased clonality in peripheral blood compared with administering chemotherapy alone. This phase 2, single-arm, neoadjuvant study (NCT05112536) aims to determine the immune mechanism of action of trilaciclib and its role in modulating antitumor immune responses in patients with TNBC.

Previously untreated patients with early-stage TNBC (N = 24) received single-dose trilaciclib monotherapy during the lead-in phase. After 7 days, patients received systemic therapy with 4 cycles of dose-dense doxorubicin plus cyclophosphamide and 12 weekly cycles of paclitaxel, with trilaciclib administered prior to the first dose of systemic therapy per cycle. Pembrolizumab from cycle 1 and/or carboplatin from cycle 5 was permitted per investigator discretion. Patients underwent curative surgery 3-5 weeks after the last dose of systemic therapy. Peripheral blood samples were collected at baseline, 7 (±1) days post trilaciclib monotherapy prior to chemotherapy, and pre dose on cycle 2, day 1. Peripheral blood mononuclear cells (PBMCs) were isolated from blood samples and cryopreserved for immune profiling via cytometry by time-of-flight (CyTOF), and for functional analysis via intracellular cytokine staining (ICS) and dimensionality reduction.

A preliminary analysis of PBMCs from 7 patients showed a decrease in peripheral myeloid-derived suppressor cells (MDSCs), monocytes, and classical dendritic cells following single-dose trilaciclib monotherapy. There were nominal changes to the frequency of peripheral CD4+ and CD8+ T cells. In 4/7 patients, trilaciclib monotherapy resulted in increased proportions of activated and polyfunctional CD4+ and CD8+ T cells producing IFNγ, TNFα, and IL-2 cytokines. Furthermore, trilaciclib enhanced the frequency of CD8+ T cells producing granzyme B and perforin.

The decrease in MDSCs and increase in functional T cells following trilaciclib monotherapy supports findings from an immune analysis of data from the phase 2 study of trilaciclib in patients with metastatic TNBC. Overall, these data suggest that the transient G1 arrest of peripheral immune cells by single-dose trilaciclib monotherapy favorably modulates immune responses by promoting the generation of polyfunctional T cells and limiting the number of MDSCs in circulation. Enrollment was completed in August 2022. The complete dataset from all 24 patients will be presented.

Citation Format: Sarah Ahn, Subing Cao, Amanda Jacobson, Melissa A. Russo, John S. Yi. Single-dose trilaciclib monotherapy potentiates antitumor immunity in the neoadjuvant setting of triple-negative breast cancer by modulating the composition and effector function of peripheral immune cells. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6674.

Successful AAV8 re-administration: Suppression of capsid-specific neutralizing antibodies by a combination treatment of bortezomib and CD20 mAb in a mouse model of Pompe disease

BACKGROUND

A major challenge to AAV mediated gene therapy is the presence of anti-AAV capsid neutralizing antibodies (NAbs), which can block viral vector transduction even at very low titers. Here we examined the ability of a combination immunosuppression (IS) treatment with bortezomib and a mouse-specific CD20 mAb to suppress anti-AAV NAbs and enable re-administration of AAV vectors of the same capsid in mice.

METHODS

An AAV8 vector (AAV8-CB-hGAA) that ubiquitously expresses human α-glucosidase was used for initial gene therapy and a second AAV8 vector (AAV8-LSP-hSEAP) that contains a liver-specific promoter to express human secreted alkaline phosphatase was used for AAV re-administration. Plasma samples were used for determination of anti-AAV8 NAb titers. Cells isolated from whole blood, spleen, and bone marrow were analyzed for B-cell depletion by flow cytometry. The efficiency of AAV re-administration was determined by the secretion of hSEAP in blood.

RESULTS

In näive mice, an eight-week IS treatment along with AAV8-CB-hGAA injection effectively depleted CD19⁺ B220⁺ B cells from blood, spleen, and bone marrow and prevented the formation of anti-AAV8 NAbs. Following administration of AAV8-LSP-hSEAP, increasing levels of hSEAP were detected in blood for up to 6 weeks, indicating successful AAV re-administration. In mice pre-immunized with AAV8-CB-hGAA, comparison of IS treatment for 8, 12, 16, and 20 weeks revealed that the 16-week IS treatment demonstrated the highest plasma hSEAP level following AAV8-LSP-hSEAP re-administration.

CONCLUSIONS

Our data suggest that this combination treatment is an effective IS approach that will allow retreatment of patients with AAV mediated gene therapy.

Abstract P3-06-03: Trilaciclib induces immune changes within the tumor microenvironment in early-stage triple-negative breast cancer

Background: In early-stage triple-negative breast cancer (TNBC), there is accumulating evidence of a correlation between tumor-infiltrating lymphocytes in tumor tissue and favorable clinical outcomes, with a high CD8+/regulatory T-cell (Treg) ratio after neoadjuvant chemotherapy being predictive of overall survival and associated with pathologic complete response (Ladoire S, et al. Br J Cancer. 2011; Park YH, et al. Nat Commun. 2020). Trilaciclib is a transient inhibitor of cyclin-dependent kinase 4/6 that is administered intravenously prior to chemotherapy. In preclinical studies, trilaciclib has been shown to have immune-enhancing effects by differentially arresting CD8+ T-cell and Treg subsets, which is followed by the faster recovery of CD8+ T cells than Tregs in the tumor microenvironment. Methods: This phase 2, single-arm, open-label study aims to evaluate neoadjuvant, single-dose trilaciclib followed by trilaciclib plus dose-dense anthracycline/cyclophosphamide and taxane in patients with early-stage TNBC (NCT05112536). Patients with previously untreated, non-metastatic, confirmed TNBC and a primary tumor ≥ 1.5 cm of any nodal status receive a single dose of trilaciclib 240 mg/m2 during the lead-in phase, followed by 4 cycles of doxorubicin 60 mg/m2 plus cyclophosphamide 600 mg/m2, and 12 weekly cycles of paclitaxel 80 mg/m2. Trilaciclib 240 mg/m2 is administered prior to the first chemotherapy dose of each cycle. Pembrolizumab 400 mg every 6 weeks starting on day 1, cycle 1, and/or carboplatin AUC 1.5 every week starting on day 1, cycle 5, is allowed per investigator discretion. Tumor biopsies and peripheral blood samples are collected prior to any treatment, 7 days ± 1 day post administration of trilaciclib, and during surgery, with an additional blood sample collection on day 1, cycle 2. The primary objective is to evaluate the immune-based mechanism of action of trilaciclib after a single dose of trilaciclib, as measured by changes in the CD8+/Treg ratio in tumor tissue. Pathologic complete response, safety and tolerability, and additional exploratory immune biomarker endpoints will also be assessed. Results: As of June 3, 2022, 9 patients with early-stage TNBC had been enrolled and 8 patients had received the trilaciclib lead-in dose and initiated doxorubicin/cyclophosphamide. Patients had a median age of 53.0 years, and all had stage II tumors at diagnosis, with 7 having ductal carcinoma. The median number of chemotherapy cycles received was 3 (range 1–6), and all 8 patients received pembrolizumab. Seven patients continue study treatment; 1 patient discontinued due to disease progression. Five patients had an adverse event (AE) related to any study treatment, including 4 patients with ≥ 1 trilaciclib-related AE. There were no grade ≥ 3 treatment-related AEs or serious AEs. On-treatment, post-trilaciclib monotherapy biopsies were available for 4 patients. Following neoadjuvant trilaciclib treatment, the median density of stromal CD8+ T cells increased from 103.1/mm2 at baseline to 229.8/mm2 at day 7. The median CD8+/Treg ratio increased in 2 patients from 1.85 at baseline to 1.90 at day 7. Conclusions: Preliminary analysis of on-treatment tumor biopsies from 4 patients suggests that a single dose of trilaciclib may modulate the immune cell composition in the tumor microenvironment to support antitumor immune responses. The increase in CD8+ T cells following 7-day neoadjuvant treatment with trilaciclib supports previous data suggesting a role in T-cell infiltration. The complete dataset from all patients (estimated enrollment: N ≈ 24) and additional biomarker analyses will be presented.

Citation Format: Michael Danso, Joyce O’Shaughnessy, Lisa S. Wang, Kailash Mosalpuria, Sara Hurvitz, Shom Goel, Sarah Ahn, Subing Cao, John S. Yi, Taofik Oyekunle, Amanda Jacobson, Andrew Beelen, Jeremy Force. Trilaciclib induces immune changes within the tumor microenvironment in early-stage triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P3-06-03.

Stress hormones are associated with inflammatory cytokines and attenuation of T-cell function in the ascites from patients with high grade serous ovarian cancer

Mounting evidence suggests that chronic stress and subsequent distress can promote ovarian cancer progression. These altered psychological states have been linked to sustained release of stress hormones, activation of the β-adrenergic receptors in ovarian cancer cells, and induction of pro-tumoral signaling pathways. In addition, data suggest that chronic stress promotes an inflammatory landscape highlighted by increased infiltration of tumor-associated macrophages into the ovarian tumor microenvironment (TME). In ovarian cancer, ascites is a unique TME comprised of tumor, and immune cells, which secrete pro-tumoral cytokines and chemokines that modulate tumor-associated immunity. However, our knowledge about how stress hormones impact the ascites TME remains limited. We hypothesized that the ascites harbors measurable levels of stress hormones, and accumulation of these in the ascites generates a pro-tumorigenic, inflammatory, and immunosuppressive TME. We evaluated ascites samples from 49 patients with high grade serous ovarian cancer (HGSOC) and quantified cortisol and stress hormones metabolites, metanephrine (MN), and normetanephrine (NMN) in all samples. We also measured 38 individual cytokines in the ascites, including several pro-inflammatory cytokines, such as IL-6, which were positively correlated to MN or NMN levels of those samples. Conversely, we found cortisol levels were negatively correlated to several pro-inflammatory cytokines. As T-cells are integral to the TME and our analyses identified cytokines in the ascites known to modulate T-cell function, we characterized ascites-derived T-cells and assessed the impact of stress hormones on the T-cell phenotype. Our data show an altered CD4+/CD8+ T-cell ratio and a heterogeneous expression of exhaustion markers in T-cells from the ascites, while ascites-derived CD8+ T-cells exposed to epinephrine had decreased co-expression CD38 and Granzyme B. To extend these findings to animal models, we subjected ovarian cancer-bearing mice to daily restraint stress, which resulted in increased tumor growth in two models. Congruent with our human analyses, we detected corticosterone, MN, and NMN in the ascites from tumor-bearing mice, and these stress hormones correlated with several inflammatory cytokines. Moreover, daily restraint stress leads to increased CD4+PD-1+/CD8+PD-1+ T-cell ratio in the ovarian tumor microenvironment. Overall, these data highlight a role of stress hormones in the ascites TME as a driver of tumor-associated inflammation, T-cell suppression, and disease progression.

Trilaciclib prior to gemcitabine plus carboplatin for metastatic triple-negative breast cancer: phase III PRESERVE 2

Triple-negative breast cancer (TNBC) is an aggressive malignancy for which cytotoxic chemotherapy remains the backbone of treatment. Trilaciclib is an intravenous cyclin-dependent kinase 4/6 inhibitor that induces transient cell cycle arrest of hematopoietic stem and progenitor cells and immune cells during chemotherapy exposure, protecting them from chemotherapy-induced damage and enhancing immune activity. Administration of trilaciclib prior to gemcitabine plus carboplatin (GCb) significantly improved overall survival (OS) compared with GCb alone in an open-label phase II trial in patients with metastatic TNBC, potentially through protection and direct activation of immune function. The randomized, double-blind, placebo-controlled, phase III PRESERVE 2 trial will evaluate the efficacy and safety of trilaciclib administered prior to GCb in patients with locally advanced unresectable or metastatic TNBC. Clinical Trial Registration: NCT04799249 (ClinicalTrials.gov).

Abstract 2543: Chronic stress promotes tumor-associated inflammation in high-grade serous ovarian cancer

A cancer diagnosis increases stress hormones levels and leads to altered psychological states. In the context of ovarian cancer (OC), chronic stress promotes tumor growth, chemoresistance and modulates immune cell populations in the tumor microenvironment (TME). Moreover, previous work from our team suggests that chronic stress promotes an increased inflammatory response in OC. Our data show an altered CD4+/CD8+ T-cell ratio and a heterogeneous expression of exhaustion markers in patients with high-grade serous ovarian cancer (HGSOC). Therefore, we hypothesized that chronic stress results in chronic inflammation and an immunosuppressed TME. To address this, we obtained ascites from 66 patients with HGSOC and measured cytokine levels using a comprehensive Cytokine/Chemokine immunoassay. Cortisol, corticosterone, and stress hormone metabolites (metanephrine and normetanephrine) levels from ascites were measured by ELISA. CD8+ T-cells isolated from OC patient ascites were stimulated with epinephrine, and flow cytometry was used to measure co-expression of CD38 activation marker and Granzyme B, an essential mediator of CD8+ T-cell killing capacity. To further establish the impact of chronic stress on tumor progression, we subjected IG10 or ID8 tumor-bearing C57/BL6 female mice to daily restraint stress. Mice were sacrificed 8-12 weeks after inoculation, data collected, and ascites stored. Results showed an increase in inflammatory cytokines (Eotaxin, IL-6, and IL-7) in recurrent tumors of HGSOC patients. IP-10 and IFN-γ were negatively associated with cortisol levels. Moreover, normetanephrine levels positively correlated with inflammatory cytokines: IL-6, MCP-1, MCP-3, VEGF, GRO, and IL-7. Metanephrine was also positively correlated with inflammatory cytokines: SCD40L, FGF-2, and MIP1α. Ascites-derived CD8+ T-cells treated with epinephrine showed decreased co-expression CD38 and Granzyme B. Additionally, data show that daily restraint stress led to increased tumor growth in ID8 and IG10 syngeneic mouse models of OC. Ascites derived from our animal models suggest a positive correlation of inflammatory cytokines VEGF, TNFα and Eotaxin, and corticosterone levels in ID8 tumor-bearing mice. These results suggest a role for stress hormones in inflammation and immunosuppression. In conclusion, inflammatory cytokines are upregulated in recurrent HGSOC ascites samples. Cytokines that regulate T-cell function were negatively associated with cortisol levels, while stress hormone metabolites correlated with higher inflammatory cytokines. Moreover, epinephrine stimulation decreased ascites-derived CD8+ T-cell function. Inflammatory cytokines correlated with corticosterone levels in ID8 tumor-bearing mice. Overall, these data suggest a role for chronic stress in inflammation and immunosuppression, impacting the efficacy of therapies that aim to restore T-cell function.

Citation Format: Alexandra N. Aquino-Acevedo, Hope Knochenhauer, Melanie Ortiz-León, Yadiel A. Rivera-López, Margarita Bonilla-Claudio, John S. Yi, Rebecca A. Previs, Guillermo N. Armaiz-Pena. Chronic stress promotes tumor-associated inflammation in high-grade serous ovarian cancer [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 2543.

Abstract 4204: CDK4/6 inhibition mitigates chemotherapy-induced immunosuppression and enhances the efficacy of chemo- immunotherapy in small cell lung cancer models

Small cell lung cancer (SCLC) is an aggressive form of lung cancer with a notably low survival rate. Chemotherapy and more recently its combination with immunotherapy are the standard of care for extensive stage SCLC. Although this combinatorial treatment provides clinical benefit, it can be hampered by the effect of chemotherapy on inducing immunosuppression. Cyclin dependent kinases 4/6 (CDK4/6) phosphorylate retinoblastoma (Rb) protein and promote proliferation of Rb-intact hematopoietic stem progenitor cells (HSPCs) by allowing cells to progress through S phase. Rb loss is a signature mutation in SCLC tumors, making these tumor cells unresponsive to CDK4/6 inhibition. Therefore, we hypothesized that CDK4/6 inhibitors could be utilized to block the proliferation of Rb-intact HSPCs and protected them from chemotherapy without altering the effect of chemotherapy on Rb-deficient SCLC cells. We treated Rb-deficient SCLC cancer cells and Rb-intact NK and T cells with increasing concentrations of cisplatin, etoposide and topotecan with or without the CDK4/6 inhibitor G1T28. Cell proliferation, apoptosis and cell cycle were analyzed using CellTiter-Glo, Annexin V staining, and PI-based cell cycle analysis. In vitro, CDK4/6 inhibition did not alter the impact of chemotherapy on Rb-deficient SCLC cell viability, whereas with Rb-intact NK and T cells, CDK4/6 inhibitor treatment induced cell cycle arrest and prevented apoptosis induced by chemotherapeutic agents. In the TKOTmG Rb-deficient mouse model of SCLC, CDK4/6 inhibition improved the efficacy of cisplatin plus etoposide. In vivo studies using the KP-1 syngeneic mouse models showed that treatment with a CDK4/6 inhibitor improved the efficacy of chemotherapy and immunotherapy individually or chemo-immunotherapy combinations by reducing the tumor growth rate and prolonging animal survival. CDK4/6i treatment prior to chemotherapy preserved white blood cell counts in comparison to chemotherapy alone. Tissue and blood immune marker analysis showed that CDK4/6 inhibitor treatment increased both the circulating and tumor-resident NK cells. Collectively, we demonstrated that CDK4/6 inhibition does not antagonize the therapeutic impact of chemotherapy on Rb-deficient SCLC cells but enhances the efficacy of chemotherapy and immunotherapy in KP-1 syngeneic SCLC mouse model. CDK4/6i also at least partially abrogated the chemotherapy-induced reductions in subpopulatons of immune cells. CDK4/6 inhibition may be considered as a therapeutic strategy for mitigating chemotherapy-induced immunosuppression and enhance antitumor immunity in SCLC patients.

Citation Format: Thiruvengadam Arumugam, Irene G. Muñoz, Alissa Poteete, Fahoa Zhang, Monique Nilsson, John S. Yi, Jessica A. Sorrentino, Andrew P. Beelen, John V. Heymach. CDK4/6 inhibition mitigates chemotherapy-induced immunosuppression and enhances the efficacy of chemo- immunotherapy in small cell lung cancer models [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 4204.

Immune cell profiles in synovial fluid after anterior cruciate ligament and meniscus injuries

Background

Anterior cruciate ligament (ACL) and meniscus tears are common knee injuries. Despite the high rate of post-traumatic osteoarthritis (PTOA) following these injuries, the contributing factors remain unclear. In this study, we characterized the immune cell profiles of normal and injured joints at the time of ACL and meniscal surgeries.

Methods

Twenty-nine patients (14 meniscus-injured and 15 ACL-injured) undergoing ACL and/or meniscus surgery but with a normal contralateral knee were recruited. During surgery, synovial fluid was aspirated from both normal and injured knees. Synovial fluid cells were pelleted, washed, and stained with an antibody cocktail consisting of fluorescent antibodies for cell surface proteins. Analysis of immune cells in the synovial fluid was performed by polychromatic flow cytometry. A broad spectrum immune cell panel was used in the first 10 subjects. Based on these results, a T cell-specific panel was used in the subsequent 19 subjects.

Results

Using the broad spectrum immune cell panel, we detected significantly more total viable cells and CD3 T cells in the injured compared to the paired normal knees. In addition, there were significantly more injured knees with T cells above a 500-cell threshold. Within the injured knees, CD4 and CD8 T cells were able to be differentiated into subsets. The frequency of total CD4 T cells was significantly different among injury types, but no statistical differences were detected among CD4 and CD8 T cell subsets by injury type.

Conclusions

Our findings provide foundational data showing that ACL and meniscus injuries induce an immune cell-rich microenvironment that consists primarily of T cells with multiple T helper phenotypes. Future studies investigating the relationship between immune cells and joint degeneration may provide an enhanced understanding of the pathophysiology of PTOA following joint injury.

Cellular changes in eculizumab early responders with generalized myasthenia gravis

Eculizumab (ECU), a C5 complement inhibitor, is approved to treat acetylcholine receptor autoantibody positive generalized myasthenia gravis (AChR MG). The clinical effect of ECU relies on inhibition of the terminal complement complex; however, the effect of ECU on lymphocytes is largely unknown. We evaluated innate and adaptive immunity among AChR MG patients (N = 3) before ECU and ≥3 months later while on stable therapy, and found reduced activation markers in memory CD4⁺ T cell subsets, increased regulatory T cell populations, and reduced frequencies of CXCR5⁺HLA-DR⁺CCR7⁺ Tfh subsets and CD11b⁺ migratory memory B cells. We observed increases within CD8⁺ T cell subsets that were terminally differentiated and senescent. Our data suggest complement inhibition with ECU modulates the adaptive immunity in patients with MG, consistent with preclinical data showing changes in complement-mediated signaling by T- and antigen-presenting cells. These findings extend our understanding of ECU's mechanism of action when treating patients with MG.

Degenerative joint changes following intra-articular fracture are more severe in mice with T cell deficiency

The inflammatory response to joint injury, specifically intra-articular fracture, has been implicated in posttraumatic arthritis development. However, the role of T cells in regulating the development of posttraumatic arthritis is unclear. We hypothesized that the absence of T cells would lead to less severe posttraumatic arthritis following intra-articular fracture. T cell-deficient, athymic nude, and wild-type C57BL/6NJ mice were assessed at 8 weeks following closed articular fracture. Joints were assessed using histologic scores of arthritis, synovitis, and bone morphology via micro computed tomography. Cells were profiled in whole blood via flow cytometry, and plasma and synovial fluid derived cytokines were quantified by multiplex analysis. Compared to C57BL/6NJ mice, nude mice had significantly greater histologic evidence of arthritis and synovitis. Whole blood immune cell profiling revealed a lower percentage of dendritic cells but increased natural killer (NK) cells in nude mice. Concurrently, nude mice had significantly higher levels of NK cells in synovial tissue. Concentrations of plasma interleukin 1β (IL-1β) and tumor necrosis factor α, and synovial fluid IL-12, IL-17, and IL-6 in both knees were greater in nude mice. Outcomes of this study suggest that T cells may play a protective regulatory role against the development of posttraumatic arthritis. Clinical significance: Lack of functional T cells exacerbated the development of posttraumatic arthritis following intra-articular fracture suggesting that critical regulators of the immune responses, contained within the T cell population, are required for protection. Future research identifying the specific T cell subsets responsible for modulating disease immunopathogenesis will lead to new therapeutic targets to mitigate posttraumatic arthritis.

Immune Tolerance-Adjusted Personalized Immunogenicity Prediction for Pompe Disease

Infantile-onset Pompe disease (IOPD) is a glycogen storage disease caused by a deficiency of acid alpha-glucosidase (GAA). Treatment with recombinant human GAA (rhGAA, alglucosidase alfa) enzyme replacement therapy (ERT) significantly improves clinical outcomes; however, many IOPD children treated with rhGAA develop anti-drug antibodies (ADA) that render the therapy ineffective. Antibodies to rhGAA are driven by T cell responses to sequences in rhGAA that differ from the individuals' native GAA (nGAA). The goal of this study was to develop a tool for personalized immunogenicity risk assessment (PIMA) that quantifies T cell epitopes that differ between nGAA and rhGAA using information about an individual's native GAA gene and their HLA DR haplotype, and to use this information to predict the risk of developing ADA. Four versions of PIMA have been developed. They use EpiMatrix, a computational tool for T cell epitope identification, combined with an HLA-restricted epitope-specific scoring feature (iTEM), to assess ADA risk. One version of PIMA also integrates JanusMatrix, a Treg epitope prediction tool to identify putative immunomodulatory (regulatory) T cell epitopes in self-proteins. Using the JanusMatrix-adjusted version of PIMA in a logistic regression model with data from 48 cross-reactive immunological material (CRIM)-positive IOPD subjects, those with scores greater than 10 were 4-fold more likely to develop ADA (p<0.03) than those that had scores less than 10. We also confirmed the hypothesis that some GAA epitopes are immunomodulatory. Twenty-one epitopes were tested, of which four were determined to have an immunomodulatory effect on T effector response in vitro. The implementation of PIMA V3J on a secure-access website would allow clinicians to input the individual HLA DR haplotype of their IOPD patient and the GAA pathogenic variants associated with each GAA allele to calculate the patient's relative risk of developing ADA, enhancing clinical decision-making prior to initiating treatment with ERT. A better understanding of immunogenicity risk will allow the implementation of targeted immunomodulatory approaches in ERT-naïve settings, especially in CRIM-positive patients, which may in turn improve the overall clinical outcomes by minimizing the development of ADA. The PIMA approach may also be useful for other types of enzyme or factor replacement therapies.

Immune cell profiling in the joint following human and murine articular fracture

OBJECTIVE

Human and in vivo animal research implicates inflammation following articular fracture as contributing to post-traumatic arthritis. However, relevant immune cell subsets present following injury are currently undefined. Immunophenotyping human and murine synovial fluid may help to identify immune cell populations that play key roles in the response to articular fracture.

METHODS

Immunophenotyping by polychromatic flow cytometry was performed on human and mouse synovial fluid following articular fracture. Specimens were collected in patients with closed ankle fracture at the time of surgical fixation and from C57BL/6 mice with closed articular knee fracture. Immune cells were collected from injured and uninjured joints in mice via a novel cell isolation method. Whole blood samples were also collected. Immunohistochemistry (IHC) was performed on mouse synovial tissue to assess for macrophages and T cells.

RESULTS

Following intra-articular fracture, the prominent human synovial fluid immune cell subset was CD3+ T cells, containing both CD4+ and CD8+ T cells. In mice, infiltration of CD45+ immune cells in synovial fluid of the fractured limb was dominated by CD19+ B cells and CD3+ T cells at 7 days after intra-articular fracture. We also detected adaptive immune cells, including macrophages, NK cells, dendritic cells and monocytes. Macrophage and T cell findings were supported by IHC of murine synovial tissue.

CONCLUSIONS

Determining specific cell populations that mediate the immune response is essential to elucidating the chain of events initiated after injury and may be an important step in identifying potential immune signatures predictive of PTA susceptibility or potential therapeutic targets.

Opportunities, barriers, and recommendations in down syndrome research

BACKGROUND

Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community.

OBJECTIVE

The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan.

METHODS

NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS.

RESULTS

This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade.

CONCLUSIONS

This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Normative dataset for plasma cytokines in healthy human adults

We determined normative data for plasma cytokines established from a cohort of 126 carefully screened healthy adults aged 18 to 64 years. Participants were enrolled to ensure an even age and sex distribution and to include at least 30% non-Caucasians. Plasma cytokines for 18 analytes were tested by multiplex immunoassay. The data are presented by age cohort (18-29 years, 30-39, 40-49, and 50-66), as well as by sex and racial background. This dataset complements published normative ranges of cellular subsets generated by comprehensive polychromatic flow cytometry analysis of the healthy human immune system [1]. These data are available to researchers and have value as a reference range for research involving peripheral cytokines.

Ipilimumab and Radiation in Patients with High-risk Resected or Regionally Advanced Melanoma

PURPOSE

In this prospective trial, we sought to assess the feasibility of concurrent administration of ipilimumab and radiation as adjuvant, neoadjuvant, or definitive therapy in patients with regionally advanced melanoma.

PATIENTS AND METHODS

Twenty-four patients in two cohorts were enrolled and received ipilimumab at 3 mg/kg every 3 weeks for four doses in conjunction with radiation; median dose was 4,000 cGy (interquartile range, 3,550-4,800 cGy). Patients in cohort 1 were treated adjuvantly; patients in cohort 2 were treated either neoadjuvantly or as definitive therapy.

RESULTS

Adverse event profiles were consistent with those previously reported with checkpoint inhibition and radiation. For the neoadjuvant/definitive cohort, the objective response rate was 64% (80% confidence interval, 40%-83%), with 4 of 10 evaluable patients achieving a radiographic complete response. An additional 3 patients in this cohort had a partial response and went on to surgical resection. With 2 years of follow-up, the 6-, 12-, and 24-month relapse-free survival for the adjuvant cohort was 85%, 69%, and 62%, respectively. At 2 years, all patients in the neoadjuvant/definitive cohort and 10/13 patients in the adjuvant cohort were still alive. Correlative studies suggested that response in some patients were associated with specific CD4+ T-cell subsets.

CONCLUSIONS

Overall, concurrent administration of ipilimumab and radiation was feasible, and resulted in a high response rate, converting some patients with unresectable disease into surgical candidates. Additional studies to investigate the combination of radiation and checkpoint inhibitor therapy are warranted.

Reduced plasmablast frequency is associated with seronegative myasthenia gravis

BACKGROUND

The immunopathology of autoimmune seronegative myasthenia gravis (SN MG) is poorly understood. Our objective was to determine immune profiles associated with a diagnosis of SN MG.

METHODS

We performed high-dimensional flow cytometry on blood samples from SN MG patients (N = 68), healthy controls (N = 46), and acetylcholine receptor antibody (AChR+) MG patients (N = 27). We compared 12 immune cell subsets in SN MG to controls using logistic modeling via a discovery-replication design. An exploratory analysis fit a multinomial model comparing AChR+ MG and controls to SN MG.

RESULTS

An increase in CD19⁺ CD20^- CD38^hi plasmablast frequencies was associated with lower odds of being a SN MG case in both the discovery and replication analyses (discovery P-value = .0003, replication P-value = .0021). Interleukin (IL) -21 producing helper T cell frequencies were associated with a diagnosis of AChR+ MG (P = .004).

CONCLUSIONS

Reduced plasmablast frequencies are strongly associated with a SN MG diagnosis and may be a useful diagnostic biomarker in the future.

Imbalance in T follicular helper cells producing IL-17 promotes pro-inflammatory responses in MuSK antibody positive myasthenia gravis

A detailed understanding of the role of Tfh cells in MuSK-antibody positive myasthenia gravis (MuSK-MG) is lacking. We characterized phenotype and function of Tfh cells in MuSK-MG patients and controls. We found similar overall Tfh and follicular regulatory (Tfr) T cell frequencies in MuSK-MG and healthy controls, but MuSK-MG patients exhibited higher frequencies of Tfh17 cells and a higher ratio of Tfh:Tfr cells. These results suggest imbalanced Tfh cell regulation, further supported by increased frequencies of CD4 T cells co-producing IL-21/IL-17 and IL-17/IFN-γ, and increased Tfh-supported IgG production. These results support a role for Tfh cell dysregulation in MuSK-MG immunopathology.

Inhibition of the transcription factor ROR-γ reduces pathogenic Th17 cells in acetylcholine receptor antibody positive myasthenia gravis

IL-17 producing CD4 T cells (Th17) cells increase significantly with disease severity in myasthenia gravis (MG) patients. To suppress the generation of Th17 cells, we examined the effect of inhibiting retinoic acid receptor-related-orphan-receptor-C (RORγ), a Th17-specific transcription factor critical for differentiation. RORγ inhibition profoundly reduced Th17 cell frequencies, including IFN-γ and IL-17 co-producing pathogenic Th17 cells. Other T helper subsets were not affected. In parallel, CD8 T cell subsets producing IL-17 and IL-17/IFN-γ were increased in MG patients and inhibited by the RORγ inhibitor. These findings provide rationale for exploration of targeted Th17 therapies, including ROR-γ inhibitors, to treat MG patients.

Establishment of normative ranges of the healthy human immune system with comprehensive polychromatic flow cytometry profiling

Existing normative flow cytometry data have several limitations including small sample sizes, incompletely described study populations, variable flow cytometry methodology, and limited depth for defining lymphocyte subpopulations. To overcome these issues, we defined high-dimensional flow cytometry reference ranges for the healthy human immune system using Human Immunology Project Consortium methodologies after carefully screening 127 subjects deemed healthy through clinical and laboratory testing. We enrolled subjects in the following age cohorts: 18–29 years, 30–39, 40–49, and 50–66 and enrolled cohorts to ensure an even gender distribution and at least 30% non-Caucasians. From peripheral blood mononuclear cells, flow cytometry reference ranges were defined for >50 immune subsets including T-cell (activation, maturation, T follicular helper and regulatory T cell), B-cell, and innate cells. We also developed a web tool for visualization of the dataset and download of raw data. This dataset provides the immunology community with a resource to compare and extract data from rigorously characterized healthy subjects across age groups, gender and race.

Pretransplant Desensitization with Costimulation Blockade and Proteasome Inhibitor Reduces DSA and Delays Antibody-Mediated Rejection in Highly Sensitized Nonhuman Primate Kidney Transplant Recipients

BACKGROUND

Patients with broad HLA sensitization have poor access to donor organs, high mortality while waiting for kidney transplant, and inferior graft survival. Although desensitization strategies permit transplantation via lowering of donor-specific antibodies, the B cell-response axis from germinal center activation to plasma cell differentiation remains intact.

METHODS

To investigate targeting the germinal center response and plasma cells as a desensitization strategy, we sensitized maximally MHC-mismatched rhesus pairs with two sequential skin transplants. We administered a proteasome inhibitor (carfilzomib) and costimulation blockade agent (belatacept) to six animals weekly for 1 month; four controls received no treatment. We analyzed blood, lymph node, bone marrow cells, and serum before desensitization, after desensitization, and after kidney transplantation.

RESULTS

The group receiving carfilzomib and belatacept exhibited significantly reduced levels of donor-specific antibodies (P=0.05) and bone marrow plasma cells (P=0.02) compared with controls, with a trend toward reduced lymph node T follicular helper cells (P=0.06). Compared with controls, carfilzomib- and belatacept-treated animals had significantly prolonged graft survival (P=0.02), and renal biopsy at 1 month showed significantly reduced antibody-mediated rejection scores (P=0.02). However, four of five animals with long-term graft survival showed gradual rebound of donor-specific antibodies and antibody-mediated rejection.

CONCLUSIONS

Desensitization using proteasome inhibition and costimulation blockade reduces bone marrow plasma cells, disorganizes germinal center responses, reduces donor-specific antibody levels, and prolongs allograft survival in highly sensitized nonhuman primates. Most animals experienced antibody-mediated rejection with humoral-response rebound, suggesting desensitization must be maintained after transplantation using ongoing suppression of the B cell response.

Daratumumab in Sensitized Kidney Transplantation: Potentials and Limitations of Experimental and Clinical Use

BACKGROUND

Donor-specific antibodies are associated with increased risk of antibody-mediated rejection and decreased allograft survival. Therefore, reducing the risk of these antibodies remains a clinical need in transplantation. Plasma cells are a logical target of therapy given their critical role in antibody production.

METHODS

To target plasma cells, we treated sensitized rhesus macaques with daratumumab (anti-CD38 mAb). Before transplant, we sensitized eight macaques with two sequential skin grafts from MHC-mismatched donors; four of them were also desensitized with daratumumab and plerixafor (anti-CXCR4). We also treated two patients with daratumumab in the context of transplant.

RESULTS

The animals treated with daratumumab had significantly reduced donor-specific antibody levels compared with untreated controls (57.9% versus 13% reduction; P<0.05) and prolonged renal graft survival (28.0 days versus 5.2 days; P<0.01). However, the reduction in donor-specific antibodies was not maintained because all recipients demonstrated rapid rebound of antibodies, with profound T cell-mediated rejection. In the two clinical patients, a combined heart and kidney transplant recipient with refractory antibody-mediated rejection and a highly sensitized heart transplant candidate, we also observed a significant decrease in class 1 and 2 donor-specific antibodies that led to clinical improvement of antibody-mediated rejection and to heart graft access.

CONCLUSIONS

Targeting CD38 with daratumumab significantly reduced anti-HLA antibodies and anti-HLA donor-specific antibodies in a nonhuman primate model and in two transplant clinical cases before and after transplant. This supports investigation of daratumumab as a potential therapeutic strategy; however, further research is needed regarding its use for both antibody-mediated rejection and desensitization.

Tacrolimus inhibits Th1 and Th17 responses in MuSK-antibody positive myasthenia gravis patients

Muscle specific tyrosine kinase antibody positive myasthenia gravis (MuSK- MG) is characterized by autoantibodies against the MuSK protein of the neuromuscular junction resulting in weakness of bulbar and proximal muscles. We previously demonstrated that patients with MuSK-MG have increased pro-inflammatory Th1 and Th17 responses. Tacrolimus, an immunosuppressant used in AChR-MG and transplantation patients, inhibits T cell responses through interference with IL-2 transcription. The therapeutic efficacy and immunological effect of tacrolimus in MuSK-MG is unclear. In the current study we examined the proliferation, phenotype and cytokine production of CD4+ and CD8+ T cells in peripheral blood mononuclear cells of MuSK-MG following a 3-day in vitro culture with or without tacrolimus. We determined that tacrolimus profoundly suppressed CD4 and CD8 T cell proliferation and significantly suppressed Th1 and Th17 responses, as demonstrated by a reduced frequency of IFN-γ, IL-2, and IL-17 producing CD4 T cells and reduced frequencies of IFN-γ and IL-2 producing CD8 T cells. Tacrolimus also inhibits pathogenic Th17 cells coproducing IL-17 and IFN-γ. In addition, tacrolimus suppressed follicular T helper cell (Tfh) and regulatory T helper cell (Treg) subsets. These findings provide preliminary support for tacrolimus as a potential alternative immunosuppressive therapy for MuSK-MG.

IL-21 Biased Alemtuzumab Induced Chronic Antibody-Mediated Rejection Is Reversed by LFA-1 Costimulation Blockade

Despite its excellent efficacy in controlling T cell mediated acute rejection, lymphocyte depletion may promote a humoral response. While T cell repopulation after depletion has been evaluated in many aspects, the B cell response has not been fully elucidated. We tested the hypothesis that the mechanisms also involve skewed T helper phenotype after lymphocytic depletion. Post-transplant immune response was measured from alemtuzumab treated hCD52Tg cardiac allograft recipients with or without anti-LFA-1 mAb. Alemtuzumab induction promoted serum DSA, allo-B cells, and CAV in humanized CD52 transgenic (hCD52Tg) mice after heterotopic heart transplantation. Additional anti-LFA-1 mAb treatment resulted in reduced DSA (Fold increase 4.75 ± 6.9 vs. 0.7 ± 0.5; p < 0.01), allo-specific B cells (0.07 ± 0.06 vs. 0.006 ± 0.002 %; p < 0.01), neo-intimal hyperplasia (56 ± 14% vs. 23 ± 13%; p < 0.05), arterial disease (77.8 ± 14.2 vs. 25.8 ± 20.1%; p < 0.05), and fibrosis (15 ± 23.3 vs. 4.3 ± 1.65%; p < 0.05) in this alemtuzumab-induced chronic antibody-mediated rejection (CAMR) model. Surprisingly, elevated serum IL-21 levels in alemtuzumab-treated mice was reduced with LFA-1 blockade. In accordance with the increased serum IL-21 level, alemtuzumab treated mice showed hyperplastic germinal center (GC) development, while the supplemental anti-LFA-1 mAb significantly reduced the GC frequency and size. We report that the incomplete T cell depletion inside of the GC leads to a systemic IL-21 dominant milieu with hyperplastic GC formation and CAMR. Conventional immunosuppression, such as tacrolimus and rapamycin, failed to reverse AMR, while co-stimulation blockade with LFA-1 corrected the GC hyperplastic response. The identification of IL-21 driven chronic AMR elucidates a novel mechanism that suggests a therapeutic approach with cytolytic induction.

Dendritic Cells Enhance Polyfunctionality of Adoptively Transferred T Cells That Target Cytomegalovirus in Glioblastoma

Median survival for glioblastoma (GBM) remains <15 months. Human cytomegalovirus (CMV) antigens have been identified in GBM but not normal brain, providing an unparalleled opportunity to subvert CMV antigens as tumor-specific immunotherapy targets. A recent trial in recurrent GBM patients demonstrated the potential clinical benefit of adoptive T-cell therapy (ATCT) of CMV phosphoprotein 65 (pp65)-specific T cells. However, ex vivo analyses from this study found no change in the capacity of CMV pp65-specific T cells to gain multiple effector functions or polyfunctionality, which has been associated with superior antitumor efficacy. Previous studies have shown that dendritic cells (DC) could further enhance tumor-specific CD8+ T-cell polyfunctionality in vivo when administered as a vaccine. Therefore, we hypothesized that vaccination with CMV pp65 RNA-loaded DCs would enhance the frequency of polyfunctional CMV pp65-specific CD8+ T cells after ATCT. Here, we report prospective results of a pilot trial in which 22 patients with newly diagnosed GBM were initially enrolled, of which 17 patients were randomized to receive CMV pp65-specific T cells with CMV-DC vaccination (CMV-ATCT-DC) or saline (CMV-ATCT-saline). Patients who received CMV-ATCT-DC vaccination experienced a significant increase in the overall frequencies of IFNγ+, TNFα+, and CCL3+ polyfunctional, CMV-specific CD8+ T cells. These increases in polyfunctional CMV-specific CD8+ T cells correlated (R = 0.7371, P = 0.0369) with overall survival, although we cannot conclude this was causally related. Our data implicate polyfunctional T-cell responses as a potential biomarker for effective antitumor immunotherapy and support a formal assessment of this combination approach in a larger randomized study.Significance: A randomized pilot trial in patients with GBM implicates polyfunctional T-cell responses as a biomarker for effective antitumor immunotherapy. Cancer Res; 78(1); 256-64. ©2017 AACR.

B cells in the pathophysiology of myasthenia gravis

Myasthenia gravis (MG) is an archetypal autoimmune disease. The pathology is characterized by autoantibodies to the acetylcholine receptor (AChR) in most patients or to muscle-specific tyrosine kinase (MuSK) in others and to a growing number of other postsynaptic proteins in smaller subsets. A decrease in the number of functional AChRs or functional interruption of the AChR within the muscle end plate of the neuromuscular junction is caused by pathogenic autoantibodies. Although the molecular immunology underpinning the pathology is well understood, much remains to be learned about the cellular immunology contributing to the production of autoantibodies. This Review documents research concerning the immunopathology of MG, bringing together evidence principally from human studies with an emphasis on the role of adaptive immunity and B cells in particular. Proposed mechanisms for autoimmunity, which take into account that different types of MG may incorporate divergent immunopathology, are offered. Muscle Nerve 57: 172-184, 2018.

Immune Activation in Early-Stage Non-Small Cell Lung Cancer Patients Receiving Neoadjuvant Chemotherapy Plus Ipilimumab

Purpose: To determine the immunologic effects of neoadjuvant chemotherapy plus ipilimumab in early-stage non-small cell lung cancer (NSCLC) patients.Experimental Design: This is a single-arm chemotherapy plus phased ipilimumab phase II study of 24 treatment-naïve patients with stage IB-IIIA NSCLC. Patients received neoadjuvant therapy consisting of 3 cycles of paclitaxel with either cisplatin or carboplatin and ipilimumab included in the last 2 cycles.Results: Chemotherapy alone had little effect on immune parameters in PBMCs. Profound CD28-dependent activation of both CD4 and CD8 cells was observed following ipilimumab. Significant increases in the frequencies of CD4⁺ cells expressing activation markers ICOS, HLA-DR, CTLA-4, and PD-1 were apparent. Likewise, increased frequencies of CD8⁺ cells expressing the same activation markers, with the exception of PD-1, were observed. We also examined 7 resected tumors and found higher frequencies of activated tumor-infiltrating lymphocytes than those observed in PBMCs. Surprisingly, we found 4 cases of preexisting tumor-associated antigens (TAA) responses against survivin, PRAME, or MAGE-A3 present in PBMC at baseline, but neither increased frequencies nor the appearance of newly detectable responses following ipilimumab therapy. Ipilimumab had little effect on the frequencies of circulating regulatory T cells and MDSCs.Conclusions: This study did not meet the primary endpoint of detecting an increase in blood-based TAA T-cell responses after ipilimumab. Collectively, these results highlight the immune activating properties of ipilimumab in early-stage NSCLC. The immune profiling data for ipilimumab alone can contribute to the interpretation of immunologic data from combined immune checkpoint blockade immunotherapies. Clin Cancer Res; 23(24); 7474-82. ©2017 AACR.

B10 Cell Frequencies and Suppressive Capacity in Myasthenia Gravis Are Associated with Disease Severity

Myasthenia gravis (MG) is a T cell-dependent, B cell-mediated disease. The mechanisms for loss of self-tolerance in this disease are not well understood, and recently described regulatory B cell (Breg) subsets have not been thoroughly investigated. B10 cells are a subset of Bregs identified by the production of the immunosuppressive cytokine, interleukin-10 (IL-10). B10 cells are known to strongly inhibit B- and T-cell inflammatory responses in animal models and are implicated in human autoimmunity. In this study, we examined quantitative and qualitative aspects of B10 cells in acetylcholine receptor autoantibody positive MG (AChR-MG) patients and healthy controls. We observed reduced B10 cell frequencies in AChR-MG patients, which inversely correlated with disease severity. Disease severity also affected the function of B10 cells, as B10 cells in the moderate/severe group of MG patients were less effective in suppressing CD4 T-cell proliferation. These results suggest that B10 cell frequencies may be a useful biomarker of disease severity, and therapeutics designed to restore B10 cell frequencies could hold promise as a treatment for this disease through restoration of self-tolerance.

Effect of therapeutic plasma exchange on immunoglobulins in myasthenia gravis

An integrated understanding of therapeutic plasma exchange (TPE) effects on immunoglobulins, autoantibodies, and natural or acquired (vaccine) protective antibodies in patients with autoimmune myasthenia gravis (MG) is lacking. Prior studies measured TPE effects in healthy volunteers or heterogeneous autoimmune disease populations. We prospectively profiled plasma IgA, IgM, IgG, IgG subclasses (IgG1-4), acetylcholine receptor autoantibodies (AChR+), and protective antibodies in patients with AChR + MG receiving TPE for an exacerbation. TPE was performed according to institutional practice and patients were profiled for up to 12 weeks. Ten patients were enrolled (median age = 72.9 years; baseline MG-Composite = 21; median TPE treatments = 6 during their first course) and all improved. The maximum decrease in all immunoglobulins, including AChR autoantibodies, was achieved on the final day of the first TPE course (∼60-70% reduction). Three weeks post-TPE, mean AChR autoantibody, total IgG, IgG1, and IgG2 titers were below the reference range and had not recovered within 20% of baseline, whereas other measured immunoglobulins approached baseline values. We did not generally observe an "overshoot" of immunoglobulins above pre-TPE levels or accelerated recovery of pathologic AChR autoantibodies. Protective antibody profiles showed similar patterns as other IgGs and were detectable at levels associated with protection from infection. A slow return to baseline for IgGs (except IgG3) was observed, and we did not observe any obvious effect of concomitant medications on this recovery. Collectively, these findings enhance our understanding of the immunological effects of TPE and further support the concept of rapid immunoglobulin depletion for the treatment of patients with MG.

An Asian perspective on improving outcomes for nasal bone fractures by establishing specific treatment options

OBJECTIVE

To report treatment outcomes of patients with different types of nasal bone fracture, following a tailored treatment protocol.

DESIGN

The patterns and the severity of the fractures were determined by a preoperative facial photo and nasal bone computed tomography (CT) retrospectively.

SETTING

A tertiary referral centre.

PARTICIPANTS

We evaluated 129 patients who underwent surgery between March 2002 and January 2014. Patients were subjected to five different treatment methods depending on the severity of injury.

MAIN OUTCOME MEASURES

Medical records were reviewed to assess rates of complications and revision surgery. Cosmetic and functional (the degree of nasal obstruction) outcomes were measured using the Likert scale from 1 (very dissatisfied, severe obstruction) to 5 (very satisfied, no obstruction).

RESULTS

The mean elapsed time from injury to surgery was 14.9 days. The overall treatment failure rate, defined as a deformity that required revision, was 6.2%. The patient satisfaction scores for aesthetic and functional outcomes were 3.9 and 4.6 respectively.

CONCLUSION

The prudent selection of patients with indication for closed reduction, and further specification of variable treatment options for the various degrees of nasal bone fracture, may be helpful in achieving an improved treatment outcome.

LEVEL OF EVIDENCE

level IV.

Polyfunctional T-Cell Signatures to Predict Protection from Cytomegalovirus after Lung Transplantation

RATIONALE

Cytomegalovirus (CMV), which is one of the most common infections after lung transplantation, is associated with chronic lung allograft dysfunction and worse post-transplantation survival. Current approaches for at-risk patients include a fixed duration of antiviral prophylaxis despite the associated cost and side effects.

OBJECTIVES

We sought to identify a specific immunologic signature that predicted protection from subsequent CMV.

METHODS

CMV-seropositive lung transplantation recipients were included in the discovery (n = 43) and validation (n = 28) cohorts. Polyfunctional CMV-specific immunity was assessed by stimulating peripheral blood mononuclear cells with CMV pp65 or IE-1 peptide pools and then by measuring T-cell expression of CD107a, IFN-γ, tumor necrosis factor-α (TNF-α), and IL-2. Recipients were prospectively monitored for subsequent viremia. A Cox proportional hazards regression model that considered cytokine responses individually and in combination was used to create a predictive model for protection from CMV reactivation. This model was then applied to the validation cohort.

MEASUREMENTS AND MAIN RESULTS

Using the discovery cohort, we identified a specific combination of polyfunctional T-cell subsets to pp65 that predicted protection from subsequent CMV viremia (concordance index 0.88 [SE, 0.087]). The model included both protective (CD107a(-)/IFN-γ(+)/IL-2(+)/TNF-α(+) CD4(+) T cells, CD107a(-)/IFN-γ(+)/IL-2(+)/TNF-α(+) CD8(+) T cells) and detrimental (CD107a(+)/IFN-γ(+)/IL-2(-)/TNF-α(-) CD8(+) T cells) subsets. The model was robust in the validation cohort (concordance index 0.81 [SE, 0.103]).

CONCLUSIONS

We identified and validated a specific T-cell polyfunctional response to CMV antigen stimulation that provides a clinically useful prediction of subsequent cytomegalovirus risk. This novel diagnostic approach could inform the optimal duration of individual prophylaxis.

Adaptive immune response to therapy in hmgcr autoantibody myopathy

INTRODUCTION

We evaluated the response to immunosuppression in a case of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR)-autoantibody myopathy.

METHODS

T- and B-cell subsets were determined by flow cytometry pre- and posttherapy.

RESULTS

Baseline immune profiling demonstrated strikingly elevated T-follicular helper (Tfh) cells and plasmablasts. Immunosuppression resulted in clinical improvement and decreased Tfh cells, plasmablasts, and autoantibodies.

CONCLUSIONS

Immune profiling in HMGCR-autoantibody myopathy suggests a B-cell-mediated disease. Tfh cells and plasmablasts may be therapeutic biomarkers.

Characterizing the Switching Thresholds of Magnetophoretic Transistors

The switching thresholds of magnetophoretic transistors for sorting cells in microfluidic environments are characterized. The transistor operating conditions require short 20-30 mA pulses of electrical current. By demonstrating both attractive and repulsive transistor modes, a single transistor architecture is used to implement the full write cycle for importing and exporting single cells in specified array sites.

Characterization of B cells in muscle-specific kinase antibody myasthenia gravis

OBJECTIVE

To characterize B-cell subsets in patients with muscle-specific tyrosine kinase (MuSK) myasthenia gravis (MG).

METHODS

In accordance with Human Immunology Project Consortium guidelines, we performed polychromatic flow cytometry and ELISA assays in peripheral blood samples from 18 patients with MuSK MG and 9 healthy controls. To complement a B-cell phenotype assay that evaluated maturational subsets, we measured B10 cell percentages, plasma B cell-activating factor (BAFF) levels, and MuSK antibody titers. Immunologic variables were compared with healthy controls and clinical outcome measures.

RESULTS

As expected, patients treated with rituximab had high percentages of transitional B cells and plasmablasts and thus were excluded from subsequent analysis. The remaining patients with MuSK MG and controls had similar percentages of total B cells and naïve, memory, isotype-switched, plasmablast, and transitional B-cell subsets. However, patients with MuSK MG had higher BAFF levels and lower percentages of B10 cells. In addition, we observed an increase in MuSK antibody levels with more severe disease.

CONCLUSIONS

We found prominent B-cell pathology in the distinct form of MG with MuSK autoantibodies. Increased BAFF levels have been described in other autoimmune diseases, including acetylcholine receptor antibody-positive MG. This finding suggests a role for BAFF in the survival of B cells in MuSK MG, which has important therapeutic implications. B10 cells, a recently described rare regulatory B-cell subset that potently blocks Th1 and Th17 responses, were reduced, which suggests a potential mechanism for the breakdown in immune tolerance in patients with MuSK MG.

Characterization of CD4 and CD8 T cell responses in MuSK myasthenia gravis

Muscle specific tyrosine kinase myasthenia gravis (MuSK MG) is a form of autoimmune MG that predominantly affects women and has unique clinical features, including prominent bulbar weakness, muscle atrophy, and excellent response to therapeutic plasma exchange. Patients with MuSK MG have predominantly IgG4 autoantibodies directed against MuSK on the postsynaptic muscle membrane. Lymphocyte functionality has not been reported in this condition. The goal of this study was to characterize T cell responses in patients with MuSK MG. Intracellular production of IFN-gamma, TNF-alpha, IL-2, IL-17, and IL-21 by CD4+ and CD8+ T cells was measured by polychromatic flow cytometry in peripheral blood samples from 11 Musk MG patients and 10 healthy controls. Only one MuSK MG patient was not receiving immunosuppressive therapy. Regulatory T cells (Treg) were also included in our analysis to determine if changes in T cell function were due to altered Treg frequencies. CD8+ T cells from MuSK MG patients had higher frequencies of polyfunctional responses than controls, and CD4+ T cells had higher IL-2, TNF-alpha, and IL-17. MuSK MG patients had a higher percentage of CD4+ T cells producing combinations of IFN-gamma/IL-2/TNF-gamma, TNF-alpha/IL-2, and IFN-gamma/TNF-alpha. Interestingly, Treg numbers and CD39 expression were not different from control values. MuSK MG patients had increased frequencies of Th1 and Th17 cytokines and were primed for polyfunctional proinflammatory responses that cannot be explained by a defect in CD39 expression or Treg number.

Exhausted CD8 T cells downregulate the IL-18 receptor and become unresponsive to inflammatory cytokines and bacterial co-infections

During many chronic infections virus-specific CD8 T cells succumb to exhaustion as they lose their ability to respond to antigenic activation. Combinations of IL-12, IL-18, and IL-21 have been shown to induce the antigen-independent production of interferon (IFN)-γ by effector and memory CD8 T cells. In this study we investigated whether exhausted CD8 T cells are sensitive to activation by these cytokines. We show that effector and memory, but not exhausted, CD8 T cells produce IFN-γ and upregulate CD25 following exposure to certain combinations of IL-12, IL-18, and IL-21. The unresponsiveness of exhausted CD8 T cells is associated with downregulation of the IL-18-receptor-α (IL-18Rα). Although IL-18Rα expression is connected with the ability of memory CD8 T cells to self-renew and efflux rhodamine 123, the IL-18Rα^lo exhausted cells remained capable of secreting this dye. To further evaluate the consequences of IL-18Rα downregulation, we tracked the fate of IL-18Rα-deficient CD8 T cells in chronically infected mixed bone marrow chimeras and discovered that IL-18Rα affects the initial but not later phases of the response. The antigen-independent responsiveness of exhausted CD8 T cells was also investigated following co-infection with Listeria monocytogenes, which induces the expression of IL-12 and IL-18. Although IL-18Rα^hi memory cells upregulated CD25 and produced IFN-γ, the IL-18Rα^lo exhausted cells failed to respond. Collectively, these findings indicate that as exhausted T cells adjust to the chronically infected environment, they lose their susceptibility to antigen-independent activation by cytokines, which compromises their ability to detect bacterial co-infections.

Ongoing viral infections can corrupt the immune defense system. One way in which this occurs is by the induction of exhaustion in the host's anti-viral CD8 T cells, a key component of the immune response. Investigating the causes and consequences of T cell exhaustion will likely provide insights into potential strategies for improving immunity to ongoing infections. In addition, there is an increasing interest in determining how underlying chronic infections broadly impact immune responses to new infections. In this study we demonstrate that exhausted anti-viral T cells downregulate the receptor for the immune system factor IL-18. This downregulation is consequential as it prevents the function of exhausted cells from being rescued by certain combinations of immune system factors, cytokines, which potently activate conventional, highly protective responses. Moreover, the loss of this receptor disfavors the accumulation of anti-viral CD8 T cells during the initial phase of the response. We also show that whereas conventional anti-viral CD8 T cells can sense a bacterial co-infection that induces IL-12 and IL-18 production, the exhausted cells fail to respond. Collectively, these studies reveal how components of the immune defense system become recalibrated during an ongoing infection, altering their ability to respond to certain new infections.

IL-21 deficiency influences CD8 T cell quality and recall responses following an acute viral infection

CD4 T cells are principal producers of IL-21 and are often required for optimal CD8 T cell responses. Therefore, we investigated the importance of IL-21 in determining the phenotypic attributes, functional quality, and maintenance of antiviral CD8 T cells following acute infection with the prototypic mouse pathogen lymphocytic choriomeningitis virus. Previous reports have documented an obligatory role for IL-21 in sustaining CD8 T cell responses during chronic infections. Here we show that the requirements for IL-21 are less stringent following acute infections; however, in the absence of IL-21, the capacity of CD8 T cells to attain the polyfunctional trait of IL-2 production is consistently reduced during both the effector and memory phases. This is further supported by in vitro studies showing that the addition of IL-21 promotes the differentiation of IL-2-producing CD8 T cells. Although the generation of memory CD8 T cells, which are capable of mounting protective recall responses, proceeds independently of IL-21, we demonstrate that IL-21 does function to support secondary responses, especially under competitive conditions. Collectively, these studies highlight the potential roles of IL-21 in determining the quality of CD8 T cell responses postinfection.

Interleukin-21: a multifunctional regulator of immunity to infections

Interleukin-21 (IL-21) is a cytokine that has broad effects on both innate and adaptive immune responses. The roles of IL-21 in determining immunity to infections are currently being defined, and notably, it has been shown that IL-21 is most critical for sustaining T cell responses during chronic viral infections. This article discusses our current understanding of the immunobiology of IL-21, as well as its known and potential roles in influencing immunity to infections.

The influence of carotid artery catheterization technique on the incidence of thromboembolism during carotid artery stenting

BACKGROUND AND PURPOSE

Thromboembolic events related to CAS continue to be the main limitation to the widespread use of this technique as a first-line treatment for carotid occlusive disease. Our aim was to evaluate thromboembolism during CAS using DWI for catheterization techniques of the carotid artery.

MATERIALS AND METHODS

Thirty-two consecutive patients with symptomatic carotid stenosis underwent CAS involving 1 of 2 carotid artery catheterization techniques: One used a 7F or 8F catheter (group 1, n = 16) and the other used a coaxial system in which a 7F or 8F catheter was used in conjunction with a 4F or 5F catheter (group 2, n = 16). DWI was performed before and after CAS. Clinical variables, the number and location of NES on DWI after CAS, were compared between the 2 groups.

RESULTS

NES on DWI occurred in 53% of all patients. The incidence of NES was significantly higher in patients 65 years of age and older versus those younger than 65 years of age (P = .013). All NESs were asymptomatic, and their rate of occurrence did not differ significantly between groups 1 and 2. The incidence of NES in the other territories that were outside that of the treated carotid artery (P = .004) and the incidence of multiple NESs (P = .04) were significantly higher in group 1.

CONCLUSIONS

NES in the other territories mainly arises from the atherosclerotic aortic arch and arch vessels during the manipulation of endoluminal devices. The carotid artery catheterization technique using the coaxial system with a 7F or 8F catheter in conjunction with a 4F or 5F catheter reduced the incidence of NES in the other territories.

T-cell exhaustion: characteristics, causes and conversion

T-cell exhaustion is characterized by the stepwise and progressive loss of T-cell functions and can culminate in the physical deletion of the responding cells. Exhaustion is well-defined during chronic lymphocytic choriomeningitis virus infection and commonly develops under conditions of antigen-persistence, which occur following many chronic infections that are of significant public health concern including hepatitis B virus, hepatitis C virus and human immunodeficiency virus infections, as well as during tumour outgrowth. Exhaustion is not a uniformly disabled setting as a gradation of phenotypic and functional defects can manifest, and these cells are distinct from prototypic effector, memory and also anergic T cells. We are gaining insights into the extrinsic and intrinsic factors that determine the severity of exhaustion. These include the duration and magnitude of antigenic activation, availability of CD4 T-cell help, the levels of stimulatory and suppressive cytokines, as well as the expression of activatory and inhibitory receptors. More information is now becoming available regarding the molecular mechanisms that attenuate the responsiveness of exhausted T cells. As the parameters that dictate exhaustion are more thoroughly defined, this is fostering the development of methods that prevent and rejuvenate functionally inferior responses. In this article we discuss our current understanding of the properties of exhausted T cells and the mechanisms that promote and maintain this state.

A vital role for interleukin-21 in the control of a chronic viral infection

Understanding the factors that regulate the induction, quality, and longevity of antiviral T cell responses is essential for devising rational strategies to prevent or combat infections. In this study, we show that interleukin-21 (IL-21), likely produced by CD4+ T cells, directly influences the generation of polyfunctional CD8+ T cells and that the number of CD4+ T cells that produce IL-21 differs markedly between acute and chronic infections. IL-21 regulates the development of CD8+ T cell exhaustion and the ability to contain chronic lymphocytic choriomeningitis virus infection. Thus, IL-21 serves as a critical helper factor that shapes the functional quality of antiviral CD8+ T cells and is required for viral control.

The requirement of reversible cysteine sulfenic acid formation for T cell activation and function

Reactive oxygen intermediates (ROI) generated in response to receptor stimulation play an important role in mediating cellular responses. We have examined the importance of reversible cysteine sulfenic acid formation in naive CD8(+) T cell activation and proliferation. We observed that, within minutes of T cell activation, naive CD8(+) T cells increased ROI levels in a manner dependent upon Ag concentration. Increased ROI resulted in elevated levels of cysteine sulfenic acid in the total proteome. Analysis of specific proteins revealed that the protein tyrosine phosphatases SHP-1 and SHP-2, as well as actin, underwent increased sulfenic acid modification following stimulation. To examine the contribution of reversible cysteine sulfenic acid formation to T cell activation, increasing concentrations of 5,5-dimethyl-1,3-cyclohexanedione (dimedone), which covalently binds to cysteine sulfenic acid, were added to cultures. Subsequent experiments demonstrated that the reversible formation of cysteine sulfenic acid was critical for ERK1/2 phosphorylation, calcium flux, cell growth, and proliferation of naive CD8(+) and CD4(+) T cells. We also found that TNF-alpha production by effector and memory CD8(+) T cells was more sensitive to the inhibition of reversible cysteine sulfenic acid formation than IFN-gamma. Together, these results demonstrate that reversible cysteine sulfenic acid formation is an important regulatory mechanism by which CD8(+) T cells are able to modulate signaling, proliferation, and function.

The Requirement of Reversible Cysteine Sulfenic Acid Formation in T Cell Activation and Function (87.40)

Reactive oxygen intermediates (ROI) generated in response to receptor stimulation play an important role in mediating cellular responses. We have examined the importance of reversible cysteine sulfenic acid formation in naïve CD8+ T cell activation and proliferation. We observed that within minutes of T cell activation, naïve CD8+ T cells increased ROI levels in a manner dependent upon antigen concentration. With increased ROI, levels of cysteine sulfenic acid were also elevated. To examine the contribution of reversible cysteine sulfenic acid formation to T cell activation increasing concentrations of 5, 5 dimethyl-1,3-cyclohexanedione (dimedone), which covalently binds to cysteine sulfenic acid, were added to cultures. Subsequent experiments demonstrated that the reversible formation of cysteine sulfenic acid was critical for ERK1/2 phosphorylation, calcium flux, cell growth, proliferation, and cytokine production of naïve CD8+ and CD4+ T cells. We also found that TNF-α production by effector and memory CD8+ T cells was more sensitive to inhibition of reversible cysteine sulfenic acid formation than IFN-γ. Together, these results demonstrate that reversible cysteine sulfenic acid formation is an important regulatory mechanism by which CD8+ T cells are able to modulate signaling, proliferation, and function.

Research supported by American Cancer Society- #RSG-04-066-01-MBC to Jason Grayson.

Electron Transport Complex I Is Required for CD8+T Cell Function

After Ag encounter, CD8+ T cells become activated and begin to proliferate. Early during infection, when Ag-specific effector CD8+ T cells are proliferating, producing cytokines, and lysing infected cells in vivo, their mitochondrial potential is increased. The purpose of the experiments presented here was to determine whether mitochondrial function was required for CD8+ T cell function. To block mitochondrial function, transgenic CD8+ T cells were incubated with increasing doses of rotenone, an inhibitor of electron transport complex I. Within minutes of T cell activation, rotenone incubation decreased the production of H(2)O(2), calcium flux, and ERK1/2 phosphorylation. Failure to undergo signal transduction resulted in a decrease in T cell division initiated by peptide-coated cells, CD3/CD28 Abs, and PMA/ionomycin stimulation. Decreased function following rotenone incubation was not restricted to naive cells, as effector and memory CD8+ T cells isolated directly ex vivo from lymphocytic choriomeningitis virus-infected mice displayed decreased production of IFN-gamma and TNF-alpha production after peptide stimulation. Furthermore, incubation with rotenone decreased degranulation of effector and memory cells, a critical step in the cytolysis of infected cells. These data suggest that electron transport complex I is required for CD8+ T cell signal transduction, proliferation, cytokine production, and degranulation.

The activation of B-Raf and Raf-1 after electroconvulsive shock in the rat hippocampus

We demonstrated that ECS activates the kinase activity of B-Raf and Raf-1 in the rat hippocampus. The activity was maximal at one minute after ECS and temporally coincided with the increased membrane translocation of Rafs and the reported activity of MAPK, but not with the phosphorylation of Rafs.

Analysis of the results of the micronucleus test in patients presenting upper digestive tract cancers and in non-cancerous subjects

A micronucleus test was performed on 75 subjects of whom 38 presented with cancer of the upper digestive tract and 37 were free of disease; the absence of cancerous or pre-cancerous lesions in this latter group was confirmed by endoscopy and vital staining. The daily levels of alcohol and tobacco consumption of the 75 subjects were determined by precise questioning: 78% of the non-cancerous subjects smoked less than 10 g of tobacco per day whereas 79% of the cancer patients smoked 10 g or more daily. The alcohol intake of 78% of the non-cancerous subjects and 63% of the cancer patients was less than 101 ml per day. Only 10% of the cancer patients had combined daily intake levels corresponding to the threshold of sensitivity of the micronucleus test as defined by previous studies. The mean frequency of micronucleated buccal cells was 0.26% in the cancer patients and 0.13% in the non-cancerous subjects. All non-cancerous patients presented a negative test. Only 5% of the cancer patients presented a micronucleated cell frequency above 1% and could thus be considered as positive. It thus appears that the micronucleus test was not significantly positive in our population of 38 cancer patients.