Absolute Count and Percentage of CD4+Lymphocytes Are Independent Predictors of Disease Progression in HIV‐Infected Persons Initiating Highly Active Antiretroviral Therapy

Combining CD4 count, CD8 count and CD4/CD8 ratio to predict risk of mortality among HIV-positive adults after therapy: a group-based multi-trajectory analysis

Introduction

Previous studies have indicated different immunological recovery trajectories based on CD4 count or CD4/CD8 ratio. However, these immune indicators are interconnected, and relying solely on one indicator may lead to inaccurate estimates. Therefore, it is essential to develop a comprehensive trajectory model that integrates CD4 count, CD8 count and CD4/CD8 ratio.

Methods

We utilized a group-based multi-trajectory model to characterize the latent cluster of recovery based on measurements of CD4 count, CD8 count and CD4/CD8 ratio over a period of up to 96 months following ART initiation. Subsequently, we investigated the characteristics associated with trajectory groups, especially sex and age. Cox model and Kaplan-Meier survival curve were employed to assess differences in all-cause, AIDS-related and non-AIDS related mortality between trajectory groups.

Results

A total of 14,718 eligible individuals were followed for a median of 55 months. Longitudinal model identified four subgroups: group 1 (32.5%, low CD4 and CD4/CD8 inversion), group 2 (25.9%, high CD8 and CD4/CD8 inversion), group 3 (27.2%, slow recovery of CD4 and CD4/CD8 inversion) and group 4 (14.4%, rapid increase of CD4 and normal CD4/CD8). Immune recovery was slower in male than in female, and in elders than in youngers. Compared to group 2, group 1 (adjusted hazard ratio [aHR]=3.28; 95% CI 2.33-4.60) and group 3 (aHR=1.56; 95% CI 1.09-2.24) had increased risk of all-cause mortality after adjusting for other factors. Besides, group 1 (aHR=2.17) and group 3 (aHR=1.58) had higher risk of non-AIDS related mortality, and group 1 (aHR=5.92) had significantly increased risk of AIDS related mortality.

Conclusion

Longitudinal trajectory analysis of multiple immune indicators can be employed to guide targeted interventions among vulnerable populations in clinical practice.

Sixteen-Week Vitamin D3 Supplementation Increases Peripheral T Cells in Overweight Black Individuals: Post hoc Analysis of a Randomized, Double-Blinded, Placebo-Controlled Trial

Background: Vitamin D is considered to modulate T-cell function, which has been implicated in the treatment of inflammatory conditions. However, there is limited knowledge on the effects of vitamin D and its influences on circulating T-cell profiles in humans, particularly in overweight Black individuals who are more likely to be vitamin D insufficient (serum 25(OH)D concentrations of ≤20 ng/mL). Thus, this study tested the hypothesis that vitamin D supplementation modulates T-cell composition, which is in a dose-dependent manner. Methods: A 16-week randomized, double-blinded, placebo-controlled trial of vitamin D3 supplementation was undertaken in 70 overweight/obese Black people (mean age = 26 years, 82% female) with 25 hydroxyvitamin D ≤ 20 ng/mL at baseline. Subjects were randomly assigned a supervised monthly oral vitamin D3 equivalent to approximately 600 IU/day (n = 17), 2000 IU/day (n = 18), 4000 IU/day (n = 18), or a placebo (n = 17). Fresh peripheral whole blood was collected and CD3+, CD4+ and CD8+ cell counts and percentages were determined by flow cytometry at baseline and at 16 weeks, among 56 subjects who were included in the analyses. Results: A statistically significant increase in CD3+% in the 2000 IU/day vitamin D3 supplementation group, and increases in CD4+% in the 2000 IU/day and 4000 IU/day vitamin D3 supplementation groups were observed (p-values < 0.05) from the changes in baseline to 16 weeks. Further adjustments for age, sex and BMI showed that 2000 IU/day vitamin D3 supplementation increased in CD3+ count, CD3%, CD4 count, and CD4%, as compared to the placebo group (p-values < 0.05). Moreover, the highest serum 25(OH)D quantile group had the highest CD3% and CD4%. Conclusions: Sixteen-week vitamin D3 supplementation increases peripheral blood T-cell numbers and percentages in overweight/obese Black patients with vitamin D insufficiency. This resulting shift in circulating T-cell composition, particularly the increase in T helper cells (CD4+ cells), suggests that vitamin D supplementation may improve immune function in Black individuals.

Clinical factors and outcomes associated with immune non-response among virally suppressed adults with HIV from Africa and the United States

A significant minority of people living with HIV (PLWH) achieve viral suppression (VS) on antiretroviral therapy (ART) but do not regain healthy CD4 counts. Clinical factors affecting this immune non-response (INR) and its effect on incident serious non-AIDS events (SNAEs) have been challenging to understand due to confounders that are difficult to control in many study settings. The U.S. Military HIV Natural History Study (NHS) and African Cohort Study (AFRICOS). PLWH with sustained VS (< 400 copies/ml for at least two years) were evaluated for INR (CD4 < 350 cells/µl at the time of sustained VS). Logistic regression estimated adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for factors associated with INR. Cox proportional hazards regression produced adjusted hazard ratios (aHRs) for factors associated with incident SNAE after sustained VS. INR prevalence was 10.8% and 25.8% in NHS and AFRICOS, respectively. Higher CD4 nadir was associated with decreased odds of INR (aOR = 0.34 [95% CI 0.29, 0.40] and aOR = 0.48 [95% CI 0.40, 0.57] per 100 cells/µl in NHS and AFRICOS, respectively). After adjustment, INR was associated with a 61% increase in relative risk of SNAE [95% CI 1.12, 2.33]. Probability of "SNAE-free" survival at 15 years since sustained VS was approximately 20% lower comparing those with and without INR; nearly equal to the differences observed by 15-year age groups. CD4 monitoring before and after VS is achieved can help identify PLWH at risk for INR. INR may be a useful clinical indicator of future risk for SNAEs.

Immune restoration in HIV-1-infected patients after 12 years of antiretroviral therapy: a real-world observational study

Using normalization of CD4 counts as the main evaluation parameter of complete immune restoration for HIV-1 patients under antiretroviral therapy (ART) might be not enough. A comprehensive evaluation system more accurately reflecting immune restoration are urgently needed. Totally, 91,805 HIV-1 patients from 17 tertiary hospitals in China during 2005–2018 were included in this study. Immune restoration and mortality were assessed. Patients initiated ART with baseline CD4 counts <50, 50–199, 200–349, 350–499, and ≥500 cells/μL, and results showed an increase in the median CD4 counts to 445 (12-year), 467 (12-year), 581 (11-year), 644 (7-year), and 768 cells/µL (5-year), as well as the CD4/CD8 ratio to 0.59 (12-year), 0.65 (12-year), 0.79 (11-year), 0.82 (7-year), 0.9 (5-year), respectively. The median CD8 count was relatively high (median range 732–845 cells/μL), regardless of the baseline CD4 counts. Furthermore, the probabilities of death in patients achieving CD4 counts ≥500 cells/μL and CD4/CD8 ratio ≥0.8 simultaneously were significantly lower than those in patients achieving either CD4 counts ≥500 cells/μL (2.77% vs 3.50%, p=0.02) or CD4/CD8 ≥ 0.8 (2.77% vs 4.28%, p<0.001) after 12-year of ART. In this study, a new binary-indicator would accurately assess immune restoration in the era of “treat all.”

SARS-CoV-2-specific T cell responses and correlations with COVID-19 patient predisposition

Coronavirus disease 2019 (COVID-19) has emerged as a global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). So far, viral targets of cellular immunity and factors determining successful mounting of T cell responses are poorly defined. We therefore analyzed cellular responses to membrane, nucleocapsid, and spike proteins in individuals suffering from moderate or severe infection and in individuals who recovered from mild disease. We demonstrate that the CoV-2-specific CD4+ T helper cell response is directed against all 3 proteins with comparable magnitude, ex vivo proliferation, and portions of responding patients. However, individuals who died were more likely to have not mounted a cellular response to the proteins. Higher patient age and comorbidity index correlated with increased frequencies of CoV-2-specific CD4+ T cells, harboring higher portions of IL-2-secreting, but lower portions of IFN-γ-secreting, cells. Diminished frequencies of membrane protein-reactive IFN-γ+ T cells were particularly associated with higher acute physiology and chronic health evaluation II scores in patients admitted to intensive care. CoV-2-specific T cells exhibited elevated PD-1 expression in patients with active disease as compared with those individuals who recovered from previous mild disease. In summary, our data suggest a link between individual patient predisposition with respect to age and comorbidity and impairment of CoV-2-specific Th1-type cellular immunity, thereby supporting a concept of altered T cell function in at-risk patients.

Incomplete Recovery of CD4 Cell Count, CD4 Percentage, and CD4/CD8 Ratio in Patients With Human Immunodeficiency Virus Infection and Suppressed Viremia During Long-term Antiretroviral Therapy

Background

The extent and duration of long-term recovery of CD4 count, CD4 percentage (CD4%), and CD4/CD8 ratio after initiation of combination antiretroviral therapy (cART) in patients with a suppressed viral load (VL) are largely unknown.

Methods

Patients infected with human immunodeficiency virus type 1 who started cART between January 2004 and January 2012 and showed persistent viral suppression (VL, <200 copies/mL) for ≥4 years were followed up at the AIDS Clinical Center in Tokyo. Change point analysis was used to determine the time point when CD4 count recovery shows a plateau, and a linear mixed model was applied to estimate the CD4 count at this change point.

Results

Data were analyzed from 752 patients (93% male; median age, 38 years; median baseline CD4 cell count, 172/µL [interquartile range CD4%, 13.8%]; CD4/CD8 ratio, 0.23). The median follow-up period was 81.2 months, and 91 patients (12.1%) were followed up for >10 years. Change point analysis showed that CD4 count, CD4%, and CD4/CD8 ratio continued to increase until 78.6, 62.2, and 64.3 months, respectively, with adjusted means of 590/µL (95% confidence interval, 29.5%, and 0.89, respectively, at the change point. Although CD4 counts ≥500/μL were achieved in 73.8% of the study patients, they were not achieved in 48.2% of those with a baseline CD4 count <100/μL. Neither the CD4% nor the CD4/CD8 ratio were normalized in a majority of patients.

Conclusions

The results showed lack of normalization of CD4 count, CD4%, and CD4/CD8 ratio to the levels seen in healthy individuals even after long-term successful cART in patients with a suppressed VL.

Development and validation of a prognostic nomogram for HIV/AIDS patients who underwent antiretroviral therapy: Data from a China population-based cohort

BACKGROUND

Accurate forecast of the death risk is crucial to the administration of people living with HIV/AIDS (PLHIV). We aimed to establish and validate an effective prognosis nomogram in PLHIV receiving antiretroviral therapy (ART).

METHODS

All the data were obtained from 2006 to 2018 in the Wenzhou area from China AIDS prevention and control information system. Factors included in the nomogram were determined by univariate and multiple Cox proportional hazard analysis based on the training set. The receiver operating characteristic (ROC) and calibration curves were used to assess its predictive accuracy and discriminative ability. Its clinical utility was also evaluated using decision curve analysis (DCA), X-tile analysis and Kaplan-Meier curve, respectively in an independent validation set.

FINDINGS

Independent prognostic factors including haemoglobin, viral load and CD4+ T-cell count were determined and contained in the nomogram. Good agreement between the prediction by nomogram and actual observation could be detected in the calibration curve for mortality, especially in the first year. In the training cohort, AUC (95% CI) and C-index (95% CI) were 0.93 (0.90, 0.96) and 0.90 (0.85, 0.96), respectively. In the validation set, the nomogram still revealed excellent discriminations [AUC (95% CI): 0.95 (0.91, 1.00)] and good calibration [C-index (95% CI): 0.92 (0.82-1.00)]. Moreover, DCA also demonstrated that the nomogram was clinical beneficial. Additionally, participants could be classified into three distinct (low, middle and high) risk groups by the nomogram.

INTERPRETATION

The nomogram presents accurate and favourable prognostic prediction for PLHIV who underwent ART.

FUNDING

This work was supported by Zhejiang Basic Public Welfare Research Project (LGF19H260011), Wenzhou Basic Public Welfare Research Project (Y20180201), the Initial Scientific Research Fund (KYQD170301), the Major Project of the Eye Hospital Wenzhou the Major Project of the Eye Hospital Wenzhou Medical University (YNZD201602). Part of this work was also funded by National Natural Science Foundation of China (81670777) and Science and Technology Innovation Activity Plan and New Talents Plan for College Students in Zhejiang Province (2019R413073). The funders had no roles in study design, data collection, data analysis, interpretation and writing of the report.

The Impact of Absolute CD4 Count and Percentage Discordance on Pneumocystis Jirovecii Pneumonia Prophylaxis in HIV-Infected Patients

Current guidelines suggest that HIV-infected patients should receive chemoprophylaxis against Pneumocystis jirovecii pneumonia (PJP) if they have a cluster determinant 4 (CD4) count <200 cells/mm³ or oropharyngeal candidiasis. Persons with CD4 percentage (CD4%) below 14% should also be considered for prophylaxis. Discordance between CD4 count and CD4% occurs in 16% to 25% of HIV-infected patients. Provider compliance with current PJP prophylaxis guidelines when such discordance is present was assessed. Electronic medical records of 429 HIV-infected individuals who had CD4 count and CD4% measured at our clinic were reviewed. CD4 count and percentage discordance was seen in 57 (13%) of 429. Patients with CD4 count >200 but CD4% <14 were significantly less likely to be prescribed PJP prophylaxis compared with those who had CD4 count <200 and CD4% >14 (29% versus 86%; odds ratio = 0.064, 95% confidence interval: 0.0168-0.2436; P < .0001). We emphasize monitoring both the absolute CD4 count and percentage to appropriately guide PJP primary and secondary prophylaxis.

Proviral Quasispecies Diversity Is Not Associated With Virologic Breakthrough or CD4+ T Cell Loss in HIV-1 Elite Controllers

Elite controllers (EC) are able to control HIV-1 replication to extremely low levels (<50 HIV-1 RNA copies/mL) in the absence of antiretroviral therapy. However, some EC experience CD4⁺ T cell loss and/or lose their ability to control HIV-1 over the course of infection. High levels of HIV-1 env proviral diversity, activated T cells and proinflammatory cytokines were pointed out as relevant biomarkers for detection of EC at risk of virologic/immunologic progression. The aim of this study was to assess the importance of proviral diversity as a prognostic marker of virologic and/or immunologic progression in EC. To this end, we analyzed plasma viremia, total HIV DNA levels, T cells dynamics, and activation/inflammatory biomarkers in EC with low (EC_LD = 4) and high (EC_HD = 6) HIV-1 env diversity. None of EC_LD and EC_HD subjects displayed evidence of immunologic progression (decrease in absolute and percentage of CD4⁺ T cells) and only one EC_HD subject presented virologic progression (≥2 consecutive viral loads measurements above the detection limit) 2–5 years after determination of proviral env diversity. Despite differences in proviral genetic diversity, the EC_LD and EC_HD subgroups displayed comparable levels of total cell-associated HIV DNA, activated CD8⁺ T (CD38⁺HLA-DR⁺) cells and plasmatic inflammatory biomarkers (IP-10, IL-18, RANTES, PDGF-AA, and CTACK). These results indicate that the genetic diversity of the HIV-1 proviral reservoir is not a surrogate marker of residual viral replication, immune activation or inflammation, nor an accurate biomarker for the prediction of virologic breakthrough or CD4⁺ T cells loss in EC.

A retrospective analysis of dental implant survival in HIV patients

AIM

This 5 years retrospective cohort survival study compared failure rates of dental implants placed in HIV (+) and HIV (-) patients relative to several risk factors.

MATERIALS AND METHODS

Between 2006 and 2015, 484 implants placed in HIV (+) patients and 805 implants placed in HIV (-) patients were assessed for survival. The effects of HIV were estimated using propensity weighting. The effects of age, smoking status, diabetes, restoration status, gender, implant type, placement site, hepatitis C status, baseline CD4 count and CD4%, post-placement average CD4%, nadir CD4%, nadir CD4 count and antiviral therapy were analysed.

RESULTS

Implants placed in HIV (+) patients and HIV (-) patients had similar failure rates (HR = 1.4, p = 0.34). Increased failure rates were observed in HIV (+) patients with baseline CD4% ≤20 (HR = 2.72, p = 0.04), post-placement CD4% average ≤20% (HR = 2.71, p = 0.04), protease inhibitor administration (HR = 2.74, p = 0.04), smoking (HR = 2.61, p = 0.05) and anterior maxillary placement (HR = 5.82, p < 0.01). Hepatitis C coinfection, viral titre, baseline CD4 count, gender, implant type and restoration type were non-contributory.

CONCLUSION

Implants placed in HIV (+) patients had similar survival rates as HIV (-) patients. Failure rates increase significantly when confounding risk factors are present in HIV (+) patients.

Prediction of Liver Disease, AIDS, and Mortality Based on Discordant Absolute and Relative Peripheral CD4 T Lymphocytes in HIV/Hepatitis C Virus-Coinfected Individuals

Hepatitis C virus (HCV)-induced liver fibrosis and splenomegaly may lead to discordance between absolute numbers and percentages of lymphocytes and subpopulations because of sequestration. We investigated lymphocyte discordance in HIV/HCV-coinfected individuals and its relationship to progression to liver disease, AIDS, and all-cause mortality. This is an observational retrospective cohort study. Adjusted hazard ratios (aHRs) with 95% confidence intervals (95% CIs) associated with liver disease, AIDS, or mortality were computed by time-updated Cox proportional hazards regression. Of 380 HIV/HCV-coinfected adult individuals followed for a median of 8.2 years, 360 individuals had a median of 11 discordant measurements corresponding to 5,080 of 9,091 paired samples (56%). Discordance alone was not associated with any of the outcomes. By multivariable analysis, a doubling of absolute or percentage CD4 cells was associated with comparable lower risks of mortality (aHR: 0.60, 95% CI: 0.53-0.67, p < .0001 and aHR: 0.67, 95% CI: 0.56-0.79, p < .0001, respectively). Higher CD4/CD8 ratio was associated with a lower mortality risk (aHR: 0.39, 95% CI: 0.22-0.71 per doubling, p = .002). Only absolute CD4 cell measurements predicted AIDS. Development of liver disease was not predicted by total lymphocyte count or subpopulations. Despite a high prevalence of lymphocyte-subpopulation discordance with HIV/HCV coinfection, absolute CD4 cell count predicted mortality and AIDS, whereas CD4 percentage only predicted mortality. Neither CD4 T lymphocyte count nor CD4 percentage was associated with liver disease in this cohort. These findings may be necessary and useful in countries where antiretroviral treatment is not initiated for all HIV-infected individuals.

CD4:CD8 Ratio and CD8 Count as Prognostic Markers for Mortality in Human Immunodeficiency Virus-Infected Patients on Antiretroviral Therapy: The Antiretroviral Therapy Cohort Collaboration (ART-CC)

Background

We investigated whether CD4:CD8 ratio and CD8 count were prognostic for all-cause, AIDS, and non-AIDS mortality in virologically suppressed patients with high CD4 count.

Methods

We used data from 13 European and North American cohorts of human immunodeficiency virus–infected, antiretroviral therapy (ART)–naive adults who started ART during 1996–2010, who were followed from the date they had CD4 count ≥350 cells/μL and were virologically suppressed (baseline). We used stratified Cox models to estimate unadjusted and adjusted (for sex, people who inject drugs, ART initiation year, and baseline age, CD4 count, AIDS, duration of ART) all-cause and cause-specific mortality hazard ratios for tertiles of CD4:CD8 ratio (0–0.40, 0.41–0.64 [reference], >0.64) and CD8 count (0–760, 761–1138 [reference], >1138 cells/μL) and examined the shape of associations using cubic splines.

Results

During 276526 person-years, 1834 of 49865 patients died (249 AIDS-related; 1076 non-AIDS-defining; 509 unknown/unclassifiable deaths). There was little evidence that CD4:CD8 ratio was prognostic for all-cause mortality after adjustment for other factors: the adjusted hazard ratio (aHR) for lower vs middle tertile was 1.11 (95% confidence interval [CI], 1.00–1.25). The association of CD8 count with all-cause mortality was U-shaped: aHR for higher vs middle tertile was 1.13 (95% CI, 1.01–1.26). AIDS-related mortality declined with increasing CD4:CD8 ratio and decreasing CD8 count. There was little evidence that CD4:CD8 ratio or CD8 count was prognostic for non-AIDS mortality.

Conclusions

In this large cohort collaboration, the magnitude of adjusted associations of CD4:CD8 ratio or CD8 count with mortality was too small for them to be useful as independent prognostic markers in virally suppressed patients on ART.

The Impact of Psychosocial Factors on Health and Retention Outcomes for People Living With HIV: Implications for Rehabilitation Counselors and Educators

Despite medical advancements that have significantly improved the health outcomes of people living with HIV (PLWH), many do not achieve optimal health outcomes due to psychosocial barriers. This 5-year retrospective longitudinal study draws upon the International Classification of Functioning, Disability, and Health (ICF) framework to conceptualize the relationships between personal and environmental factors and health and retention outcomes among a sample of 704 PLWH in Pennsylvania. A generalized estimated equations (GEE) model was used to model retention in care outcomes (at least one medical visit every 6 months) and a general linear mixed (GLM) model was used to analyze immune system health outcomes (CD4%). This exploratory study reveals that gender, age, race, use of antiretroviral (ARV) medications, use of case management service, mental health diagnosis, and alcohol use were significantly associated with retention in care, whereas race, ethnicity, gender, mental health treatment, use of ARV medications, use of case management services, and retention in care status were significantly associated with the immune system health outcome of CD4%. The results suggest a need for rehabilitation interventions to address key psychosocial issues, as rehabilitation counselors have a unique skill set to address the medical case management needs of individuals with HIV. Implications for rehabilitation counselors and educators are discussed.

Immunological and virological characterization of HIV-1 viremia controllers in the North Region of Brazil

Background

A rare phenotype of clinical non-progressors to AIDS is not well understood and the new protocol for universal treatment, may block the understanding of viral control thus it is crucial to define this controversial group.

Methods

A cohort of 30 persons followed a criteria for viremia control groups 1 (VC1; n = 2) and 2 (VC2; n = 7) and non-viral controllers (NC; n = 21) including number of years of diagnosis, LTCD4⁺, LTCD8⁺ counts, plasma viral load and the absence of ART; 241 uninfected control persons were matched to age and sex. Infected persons were regularly examined and submitted to two or three annual laboratory measurements. Polymorphisms and allele frequencies of CCR5Δ32 and SDF1–3’A were detected in the genomic DNA. Plasma levels of cytokines (IL-2, IL-4, IL-5, IL-9, IL-10, IL-13, IL-17 and IFN-y) were measured.

Results

The group investigated is originated from a miscigenetic population and demographic and social characteristics were not significantly relevant. LTCD4⁺ median values were higher among VC than NC, but significantly lower than uninfected controls. Evolution of LTCD4⁺ and LTCD8⁺ counts, showed a slight increase of LTCD4⁺ among VC, but a significant decrease in the NC. The percentage of annual change in LTCD4⁺ was also significantly different between the groups. LTCD4⁺/LTCD8⁺ ratio was inverted but not significant among the VC, thus the ratio may be a useful biomarker for the VC. A clear signature indicated a change from Th1 to Th2 cytokine profiles from VC to NC, respectively.

Conclusions

The knowledge of viral controllers characteristics in different population groups is important to define a strict universal definition for the sake of learning about the pathogenesis of HIV-1. Data on LTCD4⁺ seems to be stable and repetitive from published data, but the LTCD8⁺ response and the significance of LTCD4⁺/LTCD8⁺ ratio values are in need to further exploration as biomarkers. The change from Th1 to Th2 cytokine profile may help to design and adjust specific treatment protocols for the group.

Performance Evaluation of the MyT4 Technology for Determining ART Eligibility

Background

In resource-limited countries, CD4 T-cell (CD4) testing continues to be used for determining antiretroviral therapy (ART) initiation eligibility and opportunistic infection monitoring. To support expanded access to CD4 testing, simple and robust technologies are necessary. We conducted this study to evaluate the performance of a new Point-of-Care (POC) CD4 technology, the MyT4, compared to conventional laboratory CD4 testing.

Methods

EDTA venous blood from 200 HIV-positive patients was tested in the laboratory using the MyT4 and BD FACSCalibur^™.

Results

The MyT4 had an r² of 0.82 and a mean bias of 12.3 cells/μl. The MyT4 had total misclassifications of 14.7% and 8.8% when analyzed using ART eligibility thresholds of 350 and 500 cells/μl, respectively.

Conclusions

We conclude that the MyT4 performed well in classifying patients using the current ART initiation eligibility thresholds in Mozambique when compared to the conventional CD4 technology.

Cytokine and Chemokine Signature in Elite Versus Viremic Controllers Infected with HIV

HIV long-term nonprogressors (LTNPs) maintaining high CD4(+) T-cell counts without antiretroviral therapy (ART) are divided into elite controllers (ECs) with undetectable and viremic controllers (VCs) with low viral loads. Little is known about the long-term changes of T-cell subsets and inflammation patterns in ECs versus VCs. The aim of the study was to explore the long-term evolution of CD4(+) T-cell levels in LTNPs and to analyze cytokine profiles in ECs versus VCs. Nineteen ECs and 15 VCs were enrolled from the natural virus controller cohort (NaViC). T-cell counts were monitored over years, the mean annual change was calculated, and plasma concentrations of 25 cytokines were evaluated using a multiplex bead array. While absolute numbers of T cells did not differ between ECs and VCs over time, we observed a significant decrease of CD4(+) T-cell percentages in VCs, but not in ECs (median [interquartile range]: ECs: 37% [28-41] vs. VCs: 29% [25-34]; p = .02). ECs had lower levels of macrophage inflammatory protein-1β (MIP-1β, p = .003), interferon γ-induced protein-10 (IP-10, p = .03), and monokine induced by interferon-γ (MIG, p = .02). CD4(+) T-cell percentages inversely correlated with MIP 1-β (r = -0.42, p = .017) and IP-10 (r = -0.77, p < .0001). A subtle decline of CD4(+) T-cell percentages could be observed in VCs, but not in ECs, which was associated with higher plasma levels of proinflammatory cytokines. Hence, even low levels of HIV replication might go along with a progressive decline in CD4(+) T-cell counts in LTNPs.

POC CD4 Testing Improves Linkage to HIV Care and Timeliness of ART Initiation in a Public Health Approach: A Systematic Review and Meta-Analysis

BACKGROUND

CD4 cell count is an important test in HIV programs for baseline risk assessment, monitoring of ART where viral load is not available, and, in many settings, antiretroviral therapy (ART) initiation decisions. However, access to CD4 testing is limited, in part due to the centralized conventional laboratory network. Point of care (POC) CD4 testing has the potential to address some of the challenges of centralized CD4 testing and delays in delivery of timely testing and ART initiation. We conducted a systematic review and meta-analysis to identify the extent to which POC improves linkages to HIV care and timeliness of ART initiation.

METHODS

We searched two databases and four conference sites between January 2005 and April 2015 for studies reporting test turnaround times, proportion of results returned, and retention associated with the use of point-of-care CD4. Random effects models were used to estimate pooled risk ratios, pooled proportions, and 95% confidence intervals.

RESULTS

We identified 30 eligible studies, most of which were completed in Africa. Test turnaround times were reduced with the use of POC CD4. The time from HIV diagnosis to CD4 test was reduced from 10.5 days with conventional laboratory-based testing to 0.1 days with POC CD4 testing. Retention along several steps of the treatment initiation cascade was significantly higher with POC CD4 testing, notably from HIV testing to CD4 testing, receipt of results, and pre-CD4 test retention (all p<0.001). Furthermore, retention between CD4 testing and ART initiation increased with POC CD4 testing compared to conventional laboratory-based testing (p = 0.01). We also carried out a non-systematic review of the literature observing that POC CD4 increased the projected life expectancy, was cost-effective, and acceptable.

CONCLUSIONS

POC CD4 technologies reduce the time and increase patient retention along the testing and treatment cascade compared to conventional laboratory-based testing. POC CD4 is, therefore, a useful tool to perform CD4 testing and expedite result delivery.

Are there differences in disease progression and mortality among male and female HIV patients on antiretroviral therapy? A meta-analysis of observational cohorts

Studies examining the sex differences in morbidity and mortality among HIV/AIDS patients have yielded inconsistent results. We conducted a meta-analysis of sex differences in disease progression and mortality among HIV/AIDS patients. Medical literature databases from inception to August 2014 were searched for published observational studies assessing sex differences in immunologic and virologic response, disease progression and mortality among HIV-infected patients. Random effects meta-analyses of 115 eligible studies were conducted to obtain pooled estimates of outcomes and heterogeneity was explored in sub-group analyses. Pooled estimates showed an increased risk of progression to AIDS (relative risk [RR]=1.11,95% CI=1.02-1.21) and all-cause mortality (RR=1.23, 95% CI=1.17-1.29) among males compared to females. All-cause mortality differed by sex only in low and middle income countries. The risk of AIDS-related mortality (RR=1.03, 95% CI=0.82-1.30), immunologic failure (RR=1.19,95% CI: 0.97-1.47), virologic suppression (RR=0.98, 95% CI=0.84-1.14), virologic failure (RR=1.26, 95% CI=0.99-1.61) and the change in CD4 cell count (Weighted mean difference [WMD] = -5.15, 95% CI= -13.57 to 3.28) did not differ by sex. These findings were modified by disease severity, adherence and use of highly active antiretroviral therapy. We conclude that HIV-related disease progression and survival outcomes are poorer in males.

Microfluidic contactless conductivity cytometer for electrical cell sensing and counting

An integrated and cost-effective microfluidic contactless conductivity cytometer for cell sensing and counting.

Technical performance evaluation of the MyT4 point of care technology for CD4+ T cell enumeration

Objective

Though absolute CD4+ T cell enumeration is the primary gateway to antiretroviral therapy initiation for HIV-positive patients in all developing countries, patient access to this critical diagnostic test is relatively poor. We technically evaluated the performance of a newly developed point-of-care CD4+ T cell technology, the MyT4, compared with conventional CD4+ T cell testing technologies.

Design

Over 250 HIV-positive patients were consecutively enrolled and their blood tested on the MyT4, BD FACSCalibur, and BD FACSCount.

Results

Compared with the BD FACSCount, the MyT4 had an r² of 0.7269 and a mean bias of −23.37 cells/µl. Compared with the BD FACSCalibur, the MyT4 had an r² of 0.5825 and a mean bias of −46.58 cells/µl. Kenya currently uses a CD4+ T cell test threshold of 350 cells/µl to determine patient eligibility for antiretroviral therapy. At this threshold, the MyT4 had a sensitivity of 95.3% (95% CI: 88.4–98.7%) and a specificity of 87.9% (95% CI: 82.3–92.3%) compared with the BD FACSCount and sensitivity and specificity of 88.2% (95% CI: 79.4–94.2%) and 84.2% (95% CI: 78.2–89.2%), respectively, compared with the BD FACSCalibur. Finally, the MyT4 had a coefficient of variation of 12.80% compared with 14.03% for the BD FACSCalibur.

Conclusions

We conclude that the MyT4 performed well at the current 350 cells/µl ART initiation eligibility threshold when used by lower cadres of health care facility staff in rural clinics compared to conventional CD4+ T cell technologies.

Sex differences in HIV outcomes in the highly active antiretroviral therapy era: a systematic review

To assess sex disparities in AIDS clinical and laboratory outcomes in the highly active antiretroviral therapy (HAART) era we conducted a systematic review of the published literature on mortality, disease progression, and laboratory outcomes among persons living with HIV and starting HAART. We performed systematic PubMed and targeted bibliographic searches of observational studies published between January, 1998, and November, 2013, that included persons starting HAART and reported analyses of mortality, progression to AIDS, or virologic or immunologic treatment outcomes by sex. Risk ratios (relative risks, odd ratios, and hazard ratios) and 95% confidence intervals were obtained. Sixty-five articles were included in this review. Thirty-nine studies were from North America and Europe and 26 were from Latin America, Asia, and Africa. Forty-four studies (68%) showed no statistically significant difference in risk of mortality, progression to AIDS, or virologic or immunologic treatment outcomes by sex. Decreased risk of death among females compared to males was observed in 24 of the 25 articles that included mortality analyses [pooled risk ratio 0.72 (95% confidence interval=0.69-0.75)], and decreased risk of death or AIDS was observed in 9 of the 13 articles that examined the composite outcome [pooled risk ratio=0.91 (0.84-0.98)]. There was no significant effect of sex on the risk of progression to AIDS [pooled risk ratio=1.15 (0.99-1.31)]. In this systematic review, females starting HAART appeared to have improved survival compared to males. However, this benefit was not associated with decreased progression to either AIDS or to differences in virologic or immunologic treatment outcomes.

Monocytes expand with immune dysregulation and is associated with insulin resistance in older individuals with chronic HIV

Background

Rates of insulin resistance are increased in HIV-infected patients on stable antiretroviral therapy (ART). Such increase may partially be due to HIV-induced immune dysregulation involving monocytes (MO) and its subsets.

Materials and Methods

Cross-sectional analysis of 141 HIV-infected subjects age ≥ 40 years on stable ART. Homeostatic model assessment–insulin resistance (HOMA-IR) and rates of metabolic syndrome were calculated. Subjects were classified by fasting glucose and oral glucose tolerance test (OGTT) into clinical diabetes categories. Multi-parametric flow cytometry was used to determine MO subset percentages: [classical (CD14⁺⁺CD16⁻), intermediate (CD14⁺⁺CD16⁺), non-classical (CD14^low/+CD16⁺⁺), and a recently identified fourth (CD14^low/+CD16⁻) ‘transitional’ MO subset] and percentage of activated (CD38⁺HLA-DR⁺) CD8 T cells. Absolute levels of cells were calculated using clinical CBC and T cell subset data. Multiple plasma soluble biomarkers were assessed by Luminex technology.

Results

Median age 50 years, CD4 count (percent) 505 cells/µL (29%), and 89% male. Total MO (r = −0.23, p = 0.006) and classical and non-classical MO subsets correlated negatively with CD4 percent. No correlations were seen with CD4 count as absolute values. Log-total MO and log-classical MO predicted HOMA-IR independently of HIV immuno-virologic and diabetes risk factors (β = 0.42, p = 0.02 and β = 0.35, p = 0.02, respectively) and were increased in subjects with metabolic syndrome (p = 0.03 and p = 0.05 respectively). Total and/or subset MO levels correlated with multiple soluble plasma biomarkers including CRP, IL-6, MMP-9, MPO, SAA, SAP and tPAI-1, with tPAI-1 independently predicting HOMA-IR (β = 0.74, p<0.001).

Conclusions

MO levels increase with worsening HIV immune dysregulation as assessed by CD4 percent. CD4 percent may provide additional information about MO and metabolic risk in this population beyond absolute values. MO, and specifically classical MO, may contribute to insulin resistance and metabolic syndrome during chronic HIV infection. Multiple soluble plasma biomarkers including tPAI-1 increase with increase in MO. Levels of tPAI-1 independently predict the development of insulin resistance.

Antibody response to Achromobacter xylosoxidans during HIV infection is associated with lower CD4 levels and increased lymphocyte activation

Inflammation during HIV infection is associated with worse disease outcomes and progression. Many mechanisms have been indicted, including HIV itself, coinfections, and gut microbial translocation. Concerning microbial translocation, we hypothesized that adaptive immune responses to a specific bacterial species known to be present in gut-associated lymphoid tissue are higher among HIV-infected individuals than among HIV-uninfected controls and are associated with T cell activation and lower CD4 T cell counts. By characterizing the IgG response to Achromobacter xylosoxidans, we found that HIV-infected participants who were immunoresponsive (n = 48) had significantly lower CD4 percentages (P = 0.01), greater CD4 activation (percentages of RA(-) CD38(+)) (P = 0.03), and higher soluble CD14 (P = 0.01). HIV-positive individuals had higher anti-A. xylosoxidans IgG titers than HIV-uninfected individuals (P = 0.04). The results suggest an abnormal adaptive immune activation to gut microflora during HIV infection.

Impact of definitions of loss to follow-up on estimates of retention, disease progression, and mortality: application to an HIV program in Mozambique

Patient retention is critical to the management of chronic diseases such as human immunodeficiency virus (HIV); hence, accurate measures of loss to follow-up (LTF) are important. Many different LTF definitions have been proposed. In a cohort of 9,692 HIV-infected patients initiating antiretroviral therapy in Mozambique from 2006 to 2011, we investigated the impact of the definition of LTF on estimated rates of LTF, acquired immunodeficiency syndrome (AIDS)-defining events, and death by applying 17 different definitions of LTF gleaned from HIV literature. We further investigated the impact of 4 specific components of the LTF definitions. Cumulative incidences of LTF and AIDS-defining events were estimated by treating death as a competing risk; Kaplan-Meier techniques and variations to account for informative censoring were used to estimate rates of mortality. Estimates of LTF 2 years after treatment initiation were high and varied substantially, from 22% to 84% depending on the LTF definition used. Estimates of 2-year mortality varied from 11% to 16%, and estimates of 2-year AIDS-defining events varied from 6% to 8%. As seen here, the choice of LTF definition can greatly affect study conclusions and program evaluations. Selection of LTF definitions should be based on the study outcome, available data on clinical encounters, and the patients' visit schedules; we suggest some general guidelines.

Discordance in CD4+T-cell levels and viral loads with co-occurrence of elevated peripheral TNF-α and IL-4 in newly diagnosed HIV-TB co-infected cases

Background

Cytokines are the hallmark of immune response to different pathogens and often dictate the disease outcome. HIV infection and tuberculosis (TB) are more destructive when confronted together than either alone. Clinical data related to the immune status of HIV-TB patients before the initiation of any drug therapy is not well documented. This study aimed to collect the baseline information pertaining to the immune status of HIV-TB co-infected patients and correlate the same with CD4+T cell levels and viral loads at the time of diagnosis prior to any drug therapy.

Methodology/Principal Findings

We analyzed the cytokines, CD4+T cell levels and viral loads to determine the immune environment in HIV-TB co-infection. The study involved four categories namely, Healthy controls (n = 57), TB infected (n = 57), HIV infected (n = 59) and HIV-TB co-infected (n = 57) patients. The multi-partite comparison and correlation between cytokines, CD4+T-cell levels and viral loads prior to drug therapy, showed an altered TH1 and TH2 response, as indicated by the cytokine profiles and skewed IFN-γ/IL-10 ratio. Inadequate CD4+T cell counts in HIV-TB patients did not correlate with high viral loads and vice-versa. When compared to HIV category, 34% of HIV-TB patients had concurrent high plasma levels of IL-4 and TNF-α at the time of diagnosis. TB relapse was observed in 5 of these HIV-TB co-infected patients who also displayed high IFN-γ/IL-10 ratio.

Conclusion/Significance

With these studies, we infer (i) CD4+T-cell levels as baseline criteria to report the disease progression in terms of viral load in HIV-TB co-infected patients can be misleading and (ii) co-occurrence of high TNF-α and IL-4 levels along with a high ratio of IFN-γ/IL-10, prior to drug therapy, may increase the susceptibility of HIV-TB co-infected patients to hyper-inflammation and TB relapse.

Comparison of two methodologies for CD4⁺ T lymphocytes relative counting on immune monitoring of patients with human immunodeficiency virus

Considering that counting the percentage of CD4 T lymphocytes can add prognostic information regarding patients infected with HIV, the aim of this study was to evaluate the percentage values of CD4+ T lymphocytes from 81 patients determined by flow cytometry and estimated by flow cytometry in conjunction with a hematology counter. Means were compared through the Student's t-test. Pearson's correlation was determined, and the agreement between results was tested by Bland-Altman. The level of significance was P < 0.05. It was found a significantly higher mean difference between the relative values of CD4+ T lymphocytes to the hematologic counter (P < 0.05), for all strata studied. Positive and significant correlations (P < 0.01) were found between the strata CD4 < 200 cells/mL (r = 0.93), between 200 and 500 cells/mL (r = 0.65), and >500 cells/mL (r = 0.81). The limits of agreement were 1.0 ± 3.8% for the stratum of CD4 < 200 cells/mL, approximately 2.2 ± 13.5% for the stratum of CD4 between 200 and 500 cells/mL, and approximately 6.2 ± 20.4% for the stratum > 500 cells/mL. The differences in the percentages of CD4+ T lymphocytes obtained by different methodologies could lead to conflict when used in clinical decisions related to the treatment and care of people infected with HIV.

Discordance between CD4+ T-lymphocyte counts and percentages in HIV-infected persons with liver fibrosis

BACKGROUND

Cirrhosis of the liver can induce splenic sequestration of peripheral blood cells, recently suggested to reduce the number but not percentage of circulating CD4(+) T cells in persons uninfected with human immunodeficiency virus (HIV). We investigated whether earlier stages of liver fibrosis prior to cirrhosis were associated with discordance between CD4 count (CD4N) and CD4 percentage (CD4%) in HIV-infected patients.

METHODS

In cross-sectional analysis of 287 HIV-infected participants of the AIDS Linked to the Intravenous Experience cohort, we evaluated CD4N, CD4%, and transient elastography staging of liver fibrosis. High CD4(+) lymphocyte discordance was defined as higher CD4% relative to CD4N based on accepted clinical cutoffs; multivariable logistic regression was used to determine covariates associated with discordance.

RESULTS

Of 287 participants, 99 (34.4%) had high CD4(+) discordance, which increased to 76% of 114 participants with marked lymphopenia (total lymphocyte count [TLC] ≤1200 cells/μL). In multivariable analysis, the odds of having high CD4(+) discordance was increased in persons with significant liver fibrosis compared to those without fibrosis (odds ratio, 1.69; 95% confidence interval [CI], .95-2.96); the odds ratio of discordance increased to 2.66 (95% CI, 1.11-6.40) among the subset of participants with TLC ≤1200 cells/μL. The odds for discordance associated with cirrhosis were of similar magnitude as those observed with significant fibrosis.

CONCLUSIONS

In HIV-infected persons, liver fibrosis is associated with discordant peripheral CD4(+) lymphocyte results, especially in the setting of marked lymphopenia. Clinicians should also consider CD4% when interpreting absolute CD4(+) counts of HIV-infected persons with known or suspected liver disease, particularly if TLC is <1200 cells/μL.

Does discordancy between the CD4 count and CD4 percentage in HIV-positive individuals influence outcomes on highly active antiretroviral therapy?

INTRODUCTION

The CD4 count and CD4 percentage (CD4%) are both strong predictors of clinical disease progression in human immunodeficiency virus (HIV). Although individuals may show discordancy between their CD4 count and CD4%, the clinical relevance of this is unclear.

METHODS

Discordancy was defined where the CD4% was ≤10th percentile for a selected CD4 count range (referred to as low discordancy), within the central 80% range (concordant), or ≥90th percentile (high discordancy). Regression methods identified factors associated with low and high discordancy in untreated individuals and assessed the impact of discordancy on treatment responses to highly active antiretroviral therapy (HAART).

RESULTS

High discordancy was associated with female sex, low viral load, and white ethnicity; low discordancy was associated with black or nonwhite ethnicity, older age, and injection drug use. Clinical event rates were higher in individuals with high discordancy starting HAART, but there was no association with subsequent HIV progression by 6 months after starting HAART. CD4 count increases remained lower, by 20 cells/mm(3), in individuals with low discordancy, and higher, by 27 cells/mm(3), in those with high discordancy.

CONCLUSIONS

Overall discrepancies between the CD4/CD4% are small, confirming the use of absolute CD4 counts as a monitoring tool.

Cumulative viral load and virologic decay patterns after antiretroviral therapy in HIV-infected subjects influence CD4 recovery and AIDS

BACKGROUND

The impact of viral load (VL) decay and cumulative VL on CD4 recovery and AIDS after highly-active antiretroviral therapy (HAART) is unknown.

METHODS AND FINDINGS

Three virologic kinetic parameters (first year and overall exponential VL decay constants, and first year VL slope) and cumulative VL during HAART were estimated for 2,278 patients who initiated HAART in the U.S. Military HIV Natural History Study. CD4 and VL trajectories were computed using linear and nonlinear Generalized Estimating Equations models. Multivariate Poisson and linear regression models were used to determine associations of VL parameters with CD4 recovery, adjusted for factors known to correlate with immune recovery. Cumulative VL higher than the sample median was independently associated with an increased risk of AIDS (relative risk 2.38, 95% confidence interval 1.56-3.62, p<0.001). Among patients with VL suppression, first year VL decay and slope were independent predictors of early CD4 recovery (p = 0.001) and overall gain (p<0.05). Despite VL suppression, those with slow decay during the first year of HAART as well as during the entire therapy period (overall), in general, gained less CD4 cells compared to the other subjects (133 vs. 195.4 cells/µL; p = 0.001) even after adjusting for potential confounders.

CONCLUSIONS

In a cohort with free access to healthcare, independent of established predictors of AIDS and CD4 recovery during HAART, cumulative VL and virologic decay patterns were associated with AIDS and distinct aspects of CD4 reconstitution.

The relationship between injection and noninjection drug use and HIV disease progression

BACKGROUND

Injection drug use is associated with poor HIV outcomes even among persons receiving highly active antiretroviral therapy (HAART), but there are limited data on the relationship between noninjection drug use and HIV disease progression.

METHODS

We conducted an observational study of HIV-infected persons entering care between January 1, 1999, and December 31, 2004, with follow-up through December 31, 2005.

RESULTS

There were 1,712 persons in the study cohort: 262 with a history of injection drug use, 785 with a history of noninjection drug use, and 665 with no history of drug use; 56% were White, and 24% were females. Median follow-up was 2.1 years, 33% had HAART prior to first visit, 40% initiated first HAART during the study period, and 306 (17.9%) had an AIDS-defining event or died. Adjusting for gender, age, race, prior antiretroviral use, CD4 cell count, and HIV-1 RNA, patients with a history of injection drug use were more likely to advance to AIDS or death than nonusers (adjusted hazard ratio [HR] = 1.97, 95% confidence interval [CI] = 1.43-2.70, p < .01). There was no statistically significant difference of disease progression between noninjection drug users and nonusers (HR = 1.19, 95% CI = 0.92-1.56, p = .19). An analysis among the subgroup who initiated their first HAART during the study period (n = 687) showed a similar pattern (injection drug users: HR = 1.83, 95% CI = 1.09-3.06, p = .02; noninjection drug users: HR = 1.21, 95% CI = 0.81-1.80, p = .35). Seventy-four patients had active injection drug use during the study period, 768 active noninjection drug use, and 870 no substance use. Analyses based on active drug use during the study period did not substantially differ from those based on history of drug use.

CONCLUSIONS

This study shows no relationship between noninjection drug use and HIV disease progression. This study is limited by using history of drug use and combining different types of drugs. Further studies ascertaining specific type and extent of noninjection drug use prospectively, and with longer follow-up, are needed.

Discordance between CD4 cell count and CD4 cell percentage: implications for when to start antiretroviral therapy in HIV-1 infected children

OBJECTIVE

Antiretroviral therapy (ART) guidelines for HIV-1-infected children specify both absolute CD4 cell count and CD4 percentage thresholds at which consideration should be given to initiating ART. This leads to clinical dilemma when one marker is below the threshold, whereas the other is above.

DESIGN

Data were obtained on a large group of children followed longitudinally in trials and cohort studies in Europe and the USA. Follow-up was censored 6 months after the start of any antiretroviral drug other than zidovudine monotherapy.

METHODS

Discordance between CD4 cell count and percentage was defined in relation to ART initiation thresholds in World Health Organization (WHO) and European paediatric treatment guidelines. The relative prognostic value of CD4 cell count and percentage for progression to AIDS/death was investigated using time-updated Cox proportional hazards models, stratified by age.

RESULTS

Among 3345 children, with a total of 21,815 pairs of CD4 measurements analysed, 980 developed AIDS and/or died after a median follow-up of 1.7 years. Over one-half of children had discordant values of CD4 cell markers at the first visit when one or both treatment thresholds were crossed and approximately one-third had the same pattern of discordance at a subsequent measurement. Models suggested that CD4 percentage had little or no prognostic value over and above that contained in CD4 cell count, irrespective of age.

CONCLUSIONS

More emphasis should be placed on CD4 cell count than on CD4 percentage in deciding when to start ART in HIV-1-infected children.

Enumeration and phenotypic assessment of human plasmacytoid and myeloid dendritic cells in whole blood

Traditionally, flow cytometry analysis of dendritic cells (DC) has followed a negative selection procedure, often limiting the characterization of individual DC subsets to enumeration. We demonstrate the development, evaluation, and clinical application of a novel 6 color/8 parameter flow cytometry panel to allow enumeration and monitoring of activation status of circulating human myeloid (MDC1) and plasmacytoid (PDC) dendritic cells in human whole blood. Enumeration showed a trend of greater numbers of MDC1s and PDCs being collected for fresh whole blood than frozen PBMCs, with this difference being statistically significant (P = 0.04) for unstimulated PDC enumeration. Intra-assay variation had a coefficient of variation <10% and interassay results between operators showed good correlation (r > 0.95). Our results on fresh whole blood showed a significant up regulation of CD83 on both MDC1 and PDC at 4 h post Toll-like ligand stimulus and this activity was comparable in frozen PBMC samples. Comparison for the late activation marker CCR7 showed a significant difference (P <0.05) in expression between fresh and frozen samples, precluding its use for batch analysis of frozen samples. In addition, the level of activation is dependent on the anticoagulant used for sample collection. For CD83 expression at 4 h both EDTA and lithium heparin samples are comparable for MDC1 and PDC populations. Whereas for CCR7 expression, lithium heparin is preferable as EDTA increases the background expression in PDC, preventing further functional assessments. We demonstrate the importance of establishing the kinetic profile of activation marker expression and the importance of evaluating sample collection tubes and sample type before application of novel cytometry panels to a clinical study. We have shown that this DC enumeration flow cytometry panel is a robust analysis system that allows the flexibility of including activation markers.

Biomarkers predicting progression of human immunodeficiency virus-related disease

Biomarkers in predicting the progression of HIV infected individuals to a state of HIV disease (AIDS) are studied over more than a decade. Use of surrogate markers in the past for tracking clinical progression of the disease was limited, as little knowledge existed about the disease. The aim of this review was to address various changes in biomarker related studies taking place over the last five years, especially the trend towards use of newer biomarkers and experimentation with novel molecules in a quest for halting HIV disease progression. An open search of PUBMED database was made with search 'key words' such as 'Biomarkers' and 'AIDS (Acquired Immunodeficiency Syndrome)'.The following were the inclusion criteria for articles: a) all articles published in English language, b) years of publication between 2002-2008 and c) articles limited to adult population. This yielded a total of 417 articles. The criteria used for further judging these studies considered a) type of research design, b) number of biomarkers studied, c) validity of the biomarkers, d) techniques to assess the biomarkers and the impact of the studies in furthering biomarker research, e) sample size for the studies and f) article title or abstracts having the following key words 'biomarker' or 'biomarkers' and 'predict progression to AIDS'. A total of 27 abstracts were reviewed and 12 studies met the above criteria. These 12 different studies consisted of three reviews, four cohort designs, three cross-sectional designs, one each of an observational, and an in-vitro design. The various biomarkers emerging as a results were primarily a mix of viral, neural, immunological, HLA (human leukocyte antigen) markers along with lymphocyte counts. Although there have been quite a few advancements in biomarker-related studies, majority of the novel biomarkers discovered need to be further evaluated and replicated in bigger, long-term efficacy trials. Efforts should also be made to discover newer genetic markers of disease progression. Biomarker feedback, a new concept, can be utilized in future studies addressing prevention of HIV infection or halting disease progression.

Causes of death in HIV-infected women: persistent role of AIDS. The 'Mortalité 2000 & 2005' Surveys (ANRS EN19)

BACKGROUND

Little is known about the causes of death in human immunodeficiency virus (HIV)-infected women in the era of combination antiretroviral therapy (ART).

METHODS

In the French nationwide Mortalité 2000 and 2005 surveys, physicians reported causes of deaths in HIV-infected adults in 2000 and 2005, using a standardized questionnaire. We used multivariate logistic regression models to study the association between gender and AIDS-defining causes of death, adjusting for other characteristics.

RESULTS

Of the 1013 HIV-infected adults who died in 2005, 247 (24%) were women. Half of women were infected through heterosexual contacts, compared with 25% men. In 2005, the proportion of AIDS-defining causes of death was higher in women than in men (43 vs 34%; P = 0.01), whereas it had been the same in 2000 (47% in women and men). In 2005, women died less frequently than men from respiratory malignancies (lung, ear/nose/throat) and cardiovascular disease (9% of all causes of death in women compared with 16% in men; P = 0.004), and suicides or accidents (4 vs 9%; P = 0.02). Socio-economic precariousness, younger age, less alcohol and tobacco consumption and lack of prior ART explained the higher proportion of deaths from AIDS in women compared with men.

CONCLUSIONS

The higher proportion of AIDS-related deaths in women is probably explained by two factors: (i) some HIV-infected women, especially migrants in poor socio-economic conditions, may not have access to optimal care; and (ii) a lower prevalence of risk factors for respiratory, cardiovascular and violent deaths means that the risk of dying from non-AIDS causes may be lower in women.

Misclassification of first-line antiretroviral treatment failure based on immunological monitoring of HIV infection in resource-limited settings

BACKGROUND

The monitoring of patients with human immunodeficiency virus (HIV) infection who are treated with antiretroviral medications in resource-limited settings is typically performed by use of clinical and immunological criteria. The early identification of first-line antiretroviral treatment failure is critical to prevent morbidity, mortality, and drug resistance. Misclassification of failure may result in premature switching to second-line therapy.

METHODS

Adult patients in western Kenya had their viral loads (VLs) determined if they had adhered to first-line therapy for >6 months and were suspected of experiencing immunological failure (ie, their CD4 cell count decreased by 25% in 6 months). Misclassification of treatment failure was defined as a 25% decrease in CD4 cell count with a VL of <400 copies/mL. Logistic and tree regressions examined relationships between VL and 4 variables: CD4 T cell count (hereafter CD4 cell count), percentage of T cells expressing CD4 (hereafter CD4 cell percentage), percentage decrease in the CD4 T cell count (hereafter CD4 cell count percent decrease), and percentage decrease in the percentage of T cells expressing CD4 (hereafter CD4% percent decrease).

RESULTS

There were 149 patients who were treated for 23 months; they were identified as having a 25% decrease in CD4 cell count (from 375 to 216 cells/microL) and a CD4% percent decrease (from 19% to 15%); of these 149 patients, 86 (58%) were misclassified as having experienced treatment failure. Of 42 patients who had a 50% decrease in CD4 cell count, 18 (43%) were misclassified. In multivariate logistic regression, misclassification odds were associated with a higher CD4 cell count, a shorter duration of therapy, and a smaller CD4% percent decrease. By combining these variables, we may be able to improve our ability to predict treatment failure.

CONCLUSIONS

Immunological monitoring as a sole indicator of virological failure would lead to a premature switch to valuable second-line regimens for 58% of patients who experience a 25% decrease in CD4 cell count and for 43% patients who experience a 50% decrease in CD4 cell count, and therefore this type of monitoring should be reevaluated. Selective virological monitoring and the addition of indicators like trends CD4% percent decrease and duration of therapy may systematically improve the identification of treatment failure. VL testing is now mandatory for patients suspected of experiencing first-line treatment failure within the Academic Model Providing Access to Healthcare (AMPATH) in western Kenya, and should be considered in all resource-limited settings.

Cross-cohort heterogeneity encountered while validating a model for HIV disease progression among antiretroviral initiators

OBJECTIVE

To evaluate a model for predicting time to AIDS or death among HIV-infected persons initiating highly active antiretroviral therapy (HAART).

STUDY DESIGN AND SETTING

The model was constructed from 1,891 HAART initiators in the Collaborations in HIV Outcomes Research/US (CHORUS) cohort. The model's predictive ability was assessed using internal bootstrap validation techniques and data from 716 HAART initiators at Johns Hopkins HIV Clinical Cohort (JHHCC) in whom HIV disease was, in general, more advanced.

RESULTS

The estimated concordance statistic was 0.632 with the bootstrap method and 0.625 in JHHCC. Mean predicted and observed 3-year AIDS-free survival for JHHCC was 0.76 and 0.73 (95% confidence interval [CI], 0.69-0.77), respectively; mean predicted and observed 5-year AIDS-free survival was 0.69 and 0.57 (95% CI, 0.52-0.62), respectively. Sensitivity analyses showed that the discrepancy between predicted and observed AIDS-free survival after 3 years could be due to differences in lost-to-follow-up rates between cohorts.

CONCLUSION

The model was fair at using baseline characteristics to order patients' risk of disease progression, but did not accurately predict AIDS-free survival >3 years after HAART initiation. Different variable definitions, patient characteristics, and loss to follow-up highlight the challenges of using data from one cohort to predict AIDS-free survival in an independent cohort.

CD4+ T-cell percentage is an independent predictor of clinical progression in AIDS-free antiretroviral-naive patients with CD4+ T-cell counts >200 cells/mm3

BACKGROUND

The aim of this study was to evaluate the clinical prognostic value of the CD4+ T-cell percentage (%CD4), the CD4+/CD8+ T-cell ratio or the CD8+ T-cell count, in addition to the CD4+ T-cell count and viral load (VL) in antiretroviral-naive HIV-infected patients with CD4+ T-cell counts >200 cells/mm(3).

METHODS

Antiretroviral-naive patients (n=9,740) who were AIDS-free and had a CD4+ T-cell count >200 cells/mm(3) at their first visit after January 1997 were followed-up until treatment initiation or clinical progression (mean follow-up 17 months and 13,660 person-years). Poisson regression was used for statistical analyses.

RESULTS

Progression to AIDS-defining events (ADEs), serious ADEs and death occurred in 228 patients (crude rate 1.69 per 100 person-years), 105 patients (0.77 per 100 person-years) and 67 patients (0.49 per 100 person-years), respectively. Regarding progression to ADE, the data fit was improved when the model also included the %CD4 (Akaike's information criteria [AIC] 2,049) and, to a lesser extent, the CD4+/CD8+ T-cell ratio (AIC 2,053), in addition to CD4+ T-cell count and VL (AIC 2,056). After adjustment for VL and baseline characteristics, patients with CD4+ T-cell counts of 350-500 cells/mm(3) and %CD4<15% had an estimated incidence of ADE of 3 per 100 person-years, similar to that in patients with CD4+ T-cell counts of 200-350 cells/mm(3) and %CD4>15%. The %CD4 was also significantly associated with the risk of serious ADE. By contrast, %CD4, CD4+/CD8+ T-cell ratio or CD8+ T-cell count had no additional prognostic value for the risk of death.

CONCLUSIONS

In antiretroviral-naive HIV-infected patients with CD4+ T-cell counts >200 cells/mm(3), the %CD4 was predictive of the risk of clinical progression independently of CD4+ T-cell count and VL.

Investigation of expert rule bases, logistic regression, and non-linear machine learning techniques for predicting response to antiretroviral treatment

Background

The extreme flexibility of the HIV type-1 (HIV-1) genome makes it challenging to build the ideal antiretroviral treatment regimen. Interpretation of HIV-1 genotypic drug resistance is evolving from rule-based systems guided by expert opinion to data-driven engines developed through machine learning methods.

Methods

The aim of the study was to investigate linear and non-linear statistical learning models for classifying short-term virological outcome of antiretroviral treatment. To optimize the model, different feature selection methods were considered. Robust extra-sample error estimation and different loss functions were used to assess model performance. The results were compared with widely used rule-based genotypic interpretation systems (Stanford HIVdb, Rega and ANRS).

Results

A set of 3,143 treatment change episodes were extracted from the EuResist database. The dataset included patient demographics, treatment history and viral genotypes. A logistic regression model using high order interaction variables performed better than rule-based genotypic interpretation systems (accuracy 75.63% versus 71.74–73.89%, area under the receiver operating characteristic curve [AUC] 0.76 versus 0.68–0.70) and was equivalent to a random forest model (accuracy 76.16%, AUC 0.77). However, when rule-based genotypic interpretation systems were coupled with additional patient attributes, and the combination was provided as input to the logistic regression model, the performance increased significantly, becoming comparable to the fully data-driven methods.

Conclusions

Patient-derived supplementary features significantly improved the accuracy of the prediction of response to treatment, both with rule-based and data-driven interpretation systems. Fully data-driven models derived from large-scale data sources show promise as antiretroviral treatment decision support tools.

The cost of checking proportional hazards

Confidence intervals (CIs) and the reported predictive ability of statistical models may be misleading if one ignores uncertainty in the model selection procedure. When analyzing time-to-event data using Cox regression, one typically checks the proportional hazards (PH) assumption and subsequently alters the model to address any violations. Such an examination and correction constitute a model selection procedure, and, if not accounted for, could result in misleading CI. With the bootstrap, I study the impact of checking the PH assumption using (1) data to predict AIDS-free survival among HIV-infected patients initiating antiretroviral therapy and (2) simulated data. In the HIV study, due to non-PH, a Cox model was stratified on age quintiles. Interestingly, bootstrap CIs that ignored the PH check (always stratified on age quintiles) were wider than those which accounted for the PH check (on each bootstrap replication PH was tested and corrected through stratification only if violated). Simulations demonstrated that such a phenomenon is not an anomaly, although on average CIs widen when accounting for the PH check. In most simulation scenarios, coverage probabilities adjusting and not adjusting for the PH check were similar. However, when data were generated under a minor PH violation, the 95 per cent bootstrap CI ignoring the PH check had a coverage of 0.77 as opposed to 0.95 for CI accounting for the PH check. The impact of checking the PH assumption is greatest when the p-value of the test for PH is close to the test's chosen Type I error probability.

Coping as a multisystem construct associated with pathways mediating HIV-relevant immune function and disease progression

We review psychoneuroimmunological research linking coping with HIV disease progression and its indicators, as well as with viral and host factors that may mediate or contribute to HIV progression. Our perspective on coping broadly encompasses the attempts of multiple mental and biological systems to adapt to changing internal and environmental conditions and to reestablish homeostasis. Accordingly, we discuss studies within four dimensions of coping: cognitive (appraisals, expectancies, and explanatory style), emotional (the Type C coping pattern and related constructs), active-passive strategies and behavior patterns, and physiological (autonomic reactivity and recovery). Finally, we present a model that integrates key studies linking coping with HIV prognostic indicators and clinical disease progression. Based on empirical evidence, the model suggests plausible mechanisms by which coping may be connected to HIV progression/antiprogression factors and immunopathogenesis to affect HIV clinical progression.

On-chip counting the number and the percentage of CD4+ T lymphocytes

A novel technique is reported for counting the number and the percentage of CD4+ T lymphocytes in a polydimethylsiloxane (PDMS) microchannel. This system integrates optical fluorescence detection with resistive pulse sensing enhanced by a metal oxide semiconductor field effect transistor (MOSFET). The MOSFET signal indicates the total number of the cells passing through the detection channel, while the concurrent fluorescence signal records only the number of cells tagged with a specific fluorescent dye. The absolute count of the CD4+ T cells and its percentage to the total lymphocytes can be analyzed by combining the two counting results, which shows comparable accuracy to those from the commercial flow cytometer. The fastest observed counting rate for a single-channel microchip is 8.5 cells per second. This technique is highly promising as it could greatly reduce the cost for HIV diagnosis and treatment and make it accessible to resource-poor developing countries.