Nikolas Wada

The effect of HAART-induced HIV suppression on circulating markers of inflammation and immune activation

Objectives:To investigate the impact of HAART-induced HIV suppression on levels of 24 serological biomarkers of inflammation and immune activation. Design:A prospective cohort study. Methods:Biomarkers were measured with multiplex assays in centralized laboratories using stored serum samples contributed by 1697 men during 8903 person-visits in the Multicenter AIDS Cohort Study (MACS) from 1984 to 2009. Using generalized gamma models, we compared biomarker values across three groups, adjusting for possible confounders: HIV-uninfected (NEG); HIV-positive, HAART-naive (NAI); and HAART-exposed with HIV RNA suppressed to less than 50 copies/ml plasma (SUP). We also estimated changes in biomarker levels associated with duration of HIV suppression, using splined generalized gamma regression with a knot at 1 year. Results:Most biomarkers were relatively normalized in the SUP group relative to the NAI group; however, 12 biomarkers in the SUP group were distinct (P < 0.002) from NEG values: CXCL10, C-reactive protein (CRP), sCD14, sTNFR2, tumour necrosis factor-alpha (TNF-&agr;), sCD27, sGP130, interleukin (IL)-8, CCL13, BAFF, GM-CSF and IL-12p70. Thirteen biomarkers exhibited significant changes in the first year after viral suppression, but none changed significantly after that time. Conclusion:Biomarkers of inflammation and immune activation moved towards HIV-negative levels within the first year after HAART-induced HIV suppression. Although several markers of T-cell activation returned to levels present in HIV-negative men, residual immune activation, particularly monocyte/macrophage activation, was present. This residual immune activation may represent a therapeutic target to improve the prognosis of HIV-infected individuals receiving HAART.

Cause-Specific Life Expectancies After 35 Years of Age for Human Immunodeficiency Syndrome-Infected and Human Immunodeficiency Syndrome-Negative Individuals Followed Simultaneously in Long-term Cohort Studies, 1984–2008

Parametric and semiparametric competing risks methods were used to estimate proportions, timing, and predictors of acquired immune deficiency syndrome (AIDS)-related and non-AIDS-related mortality among individuals both positive and negative for the human immunodeficiency syndrome (HIV) in the Multicenter AIDS Cohort Study (MACS) and Womens Interagency HIV Study (WIHS) from 1984 to 2008 and 1996 to 2008, respectively. Among HIV-positive MACS participants, the proportion of deaths unrelated to AIDS increased from 6% before the introduction of highly active antiretroviral therapy (HAART) (before 1996) to 53% in the HAART era (P < 0.01); the median age of persons who died from non-AIDS-related causes after age 35 years increased from 49.0 to 66.0 years (P < 0.01). In both cohorts during the HAART era, median ages at time of non-AIDS-related death were younger for HIV-positive individuals than for comparable HIV-negative individuals (8.7 years younger in MACS (P < 0.01) and 7.6 years younger in WIHS (P < 0.01)). In a multivariate proportional cause-specific hazards model, unemployment (for non-AIDS death, hazard ratio (HR) = 1.8; for AIDS death, HR = 2.3), depression (for non-AIDS death, HR = 1.4; for AIDS death, HR = 1.4), and hepatitis B or C infection (for non-AIDS death, HR = 1.8, for AIDS death; HR = 1.4) were significantly (P < 0.05) associated with higher hazards of both non-AIDS and AIDS mortality among HIV-positive individuals in the HAART era, independent of study cohort. The results illuminate the changing face of mortality among the growing population infected with HIV.

Associations of Gestational Exposure to Famine with Energy Balance and Macronutrient Density of the Diet at Age 58 Years Differ According to the Reference Population Used

Individuals exposed to the Dutch Famine of 1944-45 during gestation have increased adiposity, which might be due to changes in energy intake, physical activity, or metabolic efficiency. We studied 357 persons born between January 1945 and March 1946 whose mothers experienced famine during or immediately preceding pregnancy, 298 persons born in the same 3 institutions during 1943 or 1947 (time controls), and 311 same-sex sibling controls. We obtained food frequency and physical activity data by questionnaire between 2003 and 2005 (mean age 58 y). We defined gestational exposure as exposure to a ration of <3762 kJ/d (<900 kcal/d) for at least 10 wk. For the whole study population, energy intake was 9225 +/- 2650 kJ/d and physical activity was 7380 +/- 4331 metabolic equivalents (MET).min/wk. Compared with time controls, gestational famine exposure was associated with 113 kJ/d (95% CI, -272, 502) higher energy intake, 0.01 percentage point (95% CI, -0.88, 0.89) higher fat density, 688 MET.min/wk (95% CI, -1398, 23) lower physical activity, and 63 kJ/d (95% CI, -130, 259) higher predicted energy expenditure (pEE). Compared with sibling controls, gestational famine exposure was associated with 4 kJ/d (95% CI, -702, 711) higher energy intake, 2.01 percentage points (95% CI, 0.38, 3.63) higher fat density, 97 MET.min/wk) (95% CI, -1243, 1050) lower physical activity score, and 188 kJ/d (95% CI, -163, 539) higher pEE. Gender-specific associations (P < 0.05 for heterogeneity) emerged for protein density and pEE using time controls and for energy intake using sibling controls. Associations were weak, differed by choice of control, and may reflect sampling variability or methodological differences. Persistent small energy imbalances could explain the increased weight of famine-exposed individuals.

Cause-specific mortality among HIV-infected individuals, by CD4(+) cell count at HAART initiation, compared with HIV-uninfected individuals.

Objectives:To compare the proportion, timing and hazards of non-AIDS death and AIDS death among men and women who initiated HAART at different CD4+ cell counts to mortality risks of HIV-uninfected persons with similar risk factors. Design:Prospective cohort studies. Methods:We used parametric mixture models to compare proportions of AIDS and non-AIDS mortality and ages at death, and multivariable Cox models to compare cause-specific hazards of mortality, across levels of CD4+ cell count at HAART initiation (⩽200 cells/&mgr;l: ‘late’, 201–350 cells/&mgr;l: ‘intermediate’, >350 cells/&mgr;l: ‘early’) and with HIV-uninfected individuals from the Multicenter AIDS Cohort Study and the Womens Interagency HIV Study. We used multiple imputation methods to address lead-time bias in sensitivity analysis. Results:Earlier initiators were more likely to die of non-AIDS causes (early: 78%, intermediate: 74%, late: 49%), and at older ages (median years 72, 69, 66), relative to later initiators. Estimated median ages at non-AIDS death for each CD4+ cell count category were lower than that estimated for the HIV-uninfected group (75 years). In multivariable analysis, non-AIDS death hazard ratios relative to early initiators were 2.15 for late initiators (P < 0.01) and 1.66 for intermediate initiators (P = 0.01); AIDS death hazard ratios were 3.26 for late initiators (P < 0.01) and 1.20 for intermediate initiators (P = 0.28). Strikingly, the adjusted hazards for non-AIDS death among HIV-uninfected individuals and early initiators were nearly identical (hazard ratio 1.01). Inferences were unchanged after adjustment for lead-time bias. Conclusion:Results suggest the possibility of reducing the risk of non-AIDS mortality among HIV-infected individuals to approximate that faced by comparable HIV-uninfected individuals.

Active tuberculosis case-finding among pregnant women presenting to antenatal clinics in soweto, South Africa

Background:Human immunodeficiency virus (HIV) and tuberculosis (TB) are among the leading causes of death among women of reproductive age worldwide. TB is a significant cause of maternal morbidity. Detection of TB during pregnancy could provide substantial benefits to women and their children. Methods:This was a cross-sectional implementation research study of integrating active TB case-finding into existing antenatal and prevention of mother-to-child transmission services in six clinics in Soweto, South Africa. All pregnant women 18 years of age or older presenting for routine care to these public clinics were screened for symptoms of active TB, cough for 2 weeks or longer, sputum production, fevers, night sweats, or weight loss, regardless of their HIV status. Participants with any symptom of active TB were asked to provide a sputum specimen for smear microscopy, mycobacterial culture and drug-susceptibility testing. Results:Between December 2008 and July 2009, 3963 pregnant women were enrolled and screened for TB, of whom 1454 (36.7%) were HIV-seropositive. Any symptom of TB was reported by 23.1% of HIV-seropositive and 13.8% of HIV-seronegative women (P < 0.01). Active pulmonary TB was diagnosed in 10 of 1454 HIV-seropositve women (688 per 100,000) and 5 of 2483 HIV-seronegative women (201 per 100,000, P = 0.03). The median CD4+ T-cell count among HIV-seropositive women with TB was similar to that of HIV-seropositive women without TB (352 versus 333 cells/μL, P = 0.85). Conclusions:There is a high burden of active TB among HIV-seropositive pregnant women. TB screening and provision of isoniazid preventive therapy and antiretroviral therapy should be integrated with prevention of mother-to-child transmission services.

Undiagnosed tuberculosis among HIV clinic attendees: association with antiretroviral therapy and implications for intensified case finding, isoniazid preventive therapy, and infection control.

Objectives:Initiation of antiretroviral therapy (ART) and the 3Is are strategies to prevent HIV-associated tuberculosis (TB). We describe factors associated with undiagnosed TB among HIV-infected patients attending an HIV clinic in South Africa and discuss implications for the 3 Is. Design:Convenience sample of HIV clinic attendees. Methods:HIV-infected participants were assessed for TB using a symptom screen, sputum-smear microscopy, sputum and blood mycobacterial culture, fine needle aspiration of enlarged lymph nodes, and chest radiography. Results:Four hundred twenty-two participants were enrolled. The median age and CD4+ T-cell count were 37 years [interquartile range (IQR): 31–44 years] and 215 cells per microliter (IQR: 107–347cells/&mgr;L). Forty-seven percent had been on ART for a median duration of 8 months (IQR: 3.3–22.8 months). Three hundred sixty-one participants (85.6%) reported TB symptoms. Twenty-seven participants (6.4%) met criteria for bacteriologically confirmed TB and 50 (11.6%) for any form of TB. Bacteriologically confirmed TB was associated with CD4+ T-cell counts ⩽100 cells per microliter (odds ratio: 5.05, 95% confidence interval: 1.69 to 15.12) when compared with CD4+ T-cell counts >200 cells per microliter and hemoglobin {hemoglobin < 10 g/dL [odds ratio 3.12 (95% confidence interval: 1.26 to 7.72)]}. Conclusions:Undiagnosed TB among HIV-infected ambulatory patients was associated with low CD4+ T-cell counts regardless of ART status. TB screening algorithms which include CD4+ T-cell count and hemoglobin testing may be an effective way to identify HIV-infected clinic attendees at highest risk of undiagnosed TB. Isoniazid preventive therapy and TB infection control are essential for reducing occurrence of HIV-associated TB even after ART initiation.

Diagnostic accuracy of a urine lipoarabinomannan enzyme-linked immunosorbent assay for screening ambulatory HIV-infected persons for tuberculosis.

Objective: To assess the diagnostic accuracy of the urine lipoarabinomannan (LAM) test among ambulatory HIV-infected persons. Design: Cross-sectional. Methods: HIV-infected persons consecutively presenting to the HIV Clinic at Tembisa Main Clinic in Ekhuruleni, South Africa, were screened for symptoms of tuberculosis (TB) and asked to provide sputum and blood samples for smears for acid-fast bacilli and mycobacterial culture and a urine specimen for a LAM enzyme-linked immunosorbent assay. Fine needle aspirates were obtained from participants with enlarged lymph nodes and sent for histopathology. Nonpregnant participants underwent chest x-ray. Results: Four hundred twenty-two HIV-infected participants were enrolled with median age 37 years (interquartile range: 31-44 years), median CD4+ T-cell count 215 cells per microliter (interquartile range: 107-347 cells/μL), and 212 (50%) receiving antiretroviral therapy. Thirty (7%) had active TB: 18 with only pulmonary TB, 5 with only extrapulmonary TB, and 7 with both pulmonary TB and extrapulmonary TB. Twenty-seven percent [95% confidence interval (CI): 12% to 48%] of TB cases were sputum acid-fast bacilli positive. The sensitivity and specificity of the urine LAM compared with the gold standard of positive bacteriology or histopathology were 32% (95% CI: 16% to 52%) and 98% (95% CI: 96% to 99%), respectively. Urine LAM had higher sensitivity in TB cases with higher bacillary burdens, though these differences were not statistically significant. Conclusions: The sensitivity of urine LAM testing is inadequate to replace mycobacterial culture. In contrast to prior research on the urine LAM, this study was conducted among less sick, ambulatory HIV-infected patients presenting for routine care.

Inflammatory Biomarkers and Mortality Risk Among HIV-Suppressed Men: A Multisite Prospective Cohort Study

BACKGROUND Human immunodeficiency virus (HIV)-induced inflammation and immune activation persist after initiation of combination antiretroviral therapy (cART) and HIV suppression and may contribute to mortality risks that exceed those in HIV-uninfected populations, though associations are unclear. METHODS In the prospective Multicenter AIDS Cohort Study, comprising men who have sex with men from Baltimore, Chicago, Los Angeles, and Pittsburgh, concentrations of 24 biomarkers of inflammation and immune activation were measured in stored serum from HIV-positive men obtained after cART-induced HIV suppression between 1996 and 2009. The outcome was nonaccidental death, with follow-up until 2014. We used Cox proportional hazards models to test whether biomarker concentrations predict time from HIV suppression to death and adjusted for multiple tests. Exploratory factor analysis (EFA) was employed to identify groupings of biomarkers that predict mortality risk. RESULTS Of 670 men followed up from HIV suppression, 54 died by the end of 2013. After adjustment for age, CD4(+) cell count, hepatitis B or C virus infection, and smoking, concentrations in the highest quartile of 4 biomarkers were significantly associated with mortality risk after controlling the false discovery rate at 5%: interleukin (IL) 6 (hazard ratio, 3.54; 95% confidence interval, 2.06-6.10), soluble IL 2Rα (3.29, 1.85-5.85), soluble CD14 (2.67, 1.55-4.61), and chemokine (CXC motif) ligand 13 (CXCL13; 2.26; 1.29-3.95). EFA yielded 2 biomarker groupings that were independent predictors of mortality risk. CONCLUSIONS Despite having undetectable HIV RNA levels during cART, men with higher concentrations of several biomarkers (particularly IL 6, soluble IL 2Rα, soluble CD14, and CXCL13) had higher hazards of long-term mortality. Correlations observed among biomarker concentrations may represent underlying inflammatory processes that contribute to mortality risk.

Non-proportionality of hazards in the competing risks framework

The simplest means of determining the effect of an exposure on the frequency and timing of two competing events is to contrast the cumulative incidences between the exposed and unexposed groups for each event type. Methods and software are widely available to semi-parametrically model the sub-hazards of the cumulative incidences as proportional and to test whether the constant relative sub-hazards (a1 and a2) are different from 1. In this chapter, we show that a1 and a2 are tethered by a strong relationship which is independent of the timing of the competing events; the relationship is fully determined by the overall frequencies of events, and a1 and a2 must be on opposite sides of 1. When violations of proportionality occur, separate analyses for the two competing events often yield an inadmissible result in which the estimates of a1 and a2 are on the same side of 1, and may even exhibit statistical significance. We further characterize the compatibility of concurrent proportionality of cause-specific hazards and sub-hazards, and show that strong tethering also occurs among these quantities; and that, of the sub-hazards and cause-specific hazards, at most two of the four can be proportional, but without restriction on which two. Because proportionality rarely holds in practice, the default analytical approach should allow the relative hazards to depend on time, which can be easily carried out with widely available software. However, the statistical power of this approach is limited in the case of large numbers of event-free observations. An application using data from a North American cohort study of children with kidney disease is presented.

Relationship Between T-Cell Responses to CMV, Markers of Inflammation, and Frailty in HIV-uninfected and HIV-infected Men in the Multicenter AIDS Cohort Study

Background Both aging and treated human immunodeficiency virus (HIV)-infected populations exhibit low-level chronic immune activation of unknown etiology, which correlates with morbidity and mortality. Cytomegalovirus (CMV) infection is common in both populations, but its relation to immune activation is unknown. Methods T cells from men who have sex with men (22 virologically suppressed HIV+, 20 HIV-) were stimulated with peptides spanning 19 CMV open reading frames, and intracellular cytokine responses were assessed. Soluble and cellular inflammatory markers were assessed by multiplex electrochemiluminescence and flow cytometry, respectively. Frailty was assessed by the Fried criteria. Results All men had responses to CMV. Proportions of CMV-responsive T cells correlated strongly (r ≥ 0.6 or ≤ -0.6; P < .05) with immunologic markers, depending on donor HIV and frailty status. Markers significantly correlated in some groups after adjustment for multiple comparisons included interferon-γ, tumor necrosis factor-α, interleukin-6, and several chemokines in serum, and the proportion of activated T cells. The magnitude of the CD4 IL-2 response significantly predicted onset of frailty in HIV- nonfrail men, but not in HIV+ nonfrail men. Conclusions T-cell responses to CMV may strongly influence chronic immune activation in HIV-uninfected and virologically suppressed HIV-infected men, and may predict frailty in HIV-uninfected men.