Shruthi Ravimohan

Early Versus Delayed Antiretroviral Therapy and Cerebrospinal Fluid Fungal Clearance in Adults With HIV and Cryptococcal Meningitis

BACKGROUND The burden of Cryptococcus neoformans in cerebrospinal fluid (CSF) predicts clinical outcomes in human immunodeficiency virus (HIV)-associated cryptococcal meningitis (CM) and is lower in patients on antiretroviral therapy (ART). This study tested the hypothesis that initiation of ART during initial treatment of HIV/CM would improve CSF clearance of C. neoformans. METHODS A randomized treatment-strategy trial was conducted in Botswana. HIV-infected, ART-naive adults aged≥21 years initiating amphotericin B treatment for CM were randomized to ART initiation within 7 (intervention) vs after 28 days (control) of randomization, and the primary outcome of the rate of CSF clearance of C. neoformans over the subsequent 4 weeks was compared. Adverse events, including CM immune reconstitution inflammatory syndrome (CM-IRIS), and immunologic and virologic responses were compared over 24 weeks. RESULTS Among 27 subjects enrolled (13 intervention and 14 control), [corrected] the median times to ART initiation were 7 (interquartile range [IQR], 5–10) and 32days (IQR, 28–36), respectively. The estimated rate of CSF clearance did not differ significantly by treatment strategy (-0.32 log10 colony-forming units [CFU]/mL/day±0.20 intervention and -0.52 log10 CFUs/mL/day (±0.48) control, P=.4). Two of 13 (15%) and 5 of 14 (36%) subjects died in the intervention and control arms, respectively (P=0.39). Seven of 13 subjects (54%) in the intervention arm vs 0 of 14 in the control arm experienced CM-IRIS (P=.002). CONCLUSIONS Early ART was not associated with improved CSF fungal clearance, but resulted in a high risk of CM-IRIS. Further research on optimal incorporation of ART into CM care is needed. CLINICAL TRIALS REGISTRATION NCT00976040.

Immunological profiling of tuberculosis-associated immune reconstitution inflammatory syndrome and non-immune reconstitution inflammatory syndrome death in HIV-infected adults with pulmonary tuberculosis starting antiretroviral therapy: a prospective observational cohort study

BACKGROUND Patients co-infected with advanced HIV and tuberculosis are at risk of tuberculosis-associated immune reconstitution inflammatory syndrome (IRIS) and death soon after initiation of antiretroviral therapy (ART). Tuberculosis-associated IRIS has been associated with quicker recovery of cellular immune responses after ART initiation and early mortality with slower recovery of these responses. We aimed to assess whether patients who have these outcomes have distinct immunological profiles before and after ART initiation. METHODS We undertook this prospective cohort study at 22 public clinics and the main public hospital in Gaborone, Botswana, in ART-naive adults (aged ≥21 years) with advanced HIV (CD4 cell counts ≤125 cells per μL) and pulmonary tuberculosis. We obtained data for clinical variables and for levels of 29 plasma biomarkers, quantified by Luminex assay. We classified patients as having tuberculosis-associated IRIS, early mortality, or survival without a diagnosis of tuberculosis-associated IRIS (controls), on the basis of outcomes recorded in the 6 months after ART initiation. We used rank-sum or χ(2) tests, and logistic regression with odds ratios (OR) and 95% CIs, to assess the association between variables measured before and 4 weeks after ART initiation with death and tuberculosis-associated IRIS, compared with controls. FINDINGS Between Nov 12, 2009, and July 3, 2013, we enrolled 201 participants. 31 (15%) patients left the study before ART initiation, leaving 170 (85%) patients for analysis. Patients with tuberculosis-associated IRIS had reduced pre-ART concentrations of several pro-inflammatory biomarkers, including interleukin (IL)-6 (adjusted OR per 1 log10 increase 0·40 [95% CI 0·18-0·89]). However, patients with early death had increased pre-ART concentrations of inflammatory biomarkers, including monocyte chemoattractant protein-1 (adjusted OR 9·0 [95% CI 1·0-80·0]) and tumour necrosis factor (TNF)α (7·8 [1·1-55·2]). At week 4 after ART initation, tuberculosis-associated IRIS was independently associated with greater increases in several inflammatory biomarkers, including IL-6 (adjusted OR 1·7 [95% CI 1·2-2·5]) and TNFα (1·5 [1·0-2·2]), versus controls. Death was likewise associated with greater increases in systemic inflammatory markers, including granulocyte colony-stimulating factor (adjusted OR 2·8 [95% CI 1·3-6·1]), IL-12p40 (1·8 [1·0-3·4]), and IL-15 (2·0 [1·1-3·7]), versus controls. However, changes in CD4 cell count during ART, which were similar between controls and patients with tuberculosis-associated IRIS (p=0·45), were substantially lower in patients who died (p=0·006). INTERPRETATION Distinct immunological profiles before and after ART initiation characterise patients with advanced HIV and tuberculosis who have tuberculosis-associated IRIS and death. Interventions that decrease inflammation while promoting cellular immune recovery during ART should be considered in patients co-infected with HIV and tuberculosis. FUNDING National Institutes of Health and the Penn Center for AIDS Research.

Early Immunologic Failure is Associated With Early Mortality Among Advanced HIV–Infected Adults Initiating Antiretroviral Therapy With Active Tuberculosis

BACKGROUND The relationship between antiretroviral therapy (ART) response and early mortality after ART initiation is unknown. We hypothesized that early mortality is associated with decreased early immunologic response to ART. METHODS We prospectively determined the association between changes in plasma human immunodeficiency virus type 1 (HIV-1) RNA and CD4(+) T-cell counts (CD4 count) after 4 weeks of ART and early mortality in adults with pulmonary tuberculosis and pre-ART CD4 counts ≤ 125 cells/µL. Purified protein derivative (PPD)-specific immune recovery was determined by interferon-γ enzyme-linked immunosorbent spot assays. Levels of interleukin 6, C-reactive protein, and soluble CD14 were assessed. Patients with CD4 count and viral load values at baseline and week 4 were analyzed using multiple logistic regression. RESULTS Early immunologic response, but not pre-ART CD4 counts or virologic response, was related to early mortality (8 [interquartile range {IQR}, -18 to 43] vs 68 [IQR, 24-131] cells/µL, P = .002). In a logistic regression model, every 20 cells/µL increase in the CD4 count from baseline to week 4 was independently associated with a 40% reduction in the odds of death (odds ratio, 0.59 [95% confidence interval, .41-.87]). PPD-specific immune recovery was lower, whereas levels of immune activation were higher, among deaths. CONCLUSIONS Early immunologic failure despite virologic suppression is associated with early mortality after ART initiation in advanced HIV/tuberculosis.

Robust Reconstitution of Tuberculosis-Specific Polyfunctional CD4+ T-Cell Responses and Rising Systemic Interleukin 6 in Paradoxical Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome

BACKGROUND The immunopathogenesis of paradoxical tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) remains unclear. We determined the association between pathogen-specific T-cell responses and development of paradoxical TB-IRIS on antiretroviral therapy (ART). METHODS This study was nested within a prospective cohort study of HIV-infected patients with active pulmonary tuberculosis and baseline CD4 counts ≤125 cells/µL initiating ART. T-cell immune activation (CD38, HLA-DR, and PD-1 expression), phenotype, and polyfunctional pathogen-specific cellular immune responses prior to and 4 weeks after ART initiation were determined by flow cytometry. Patients with TB-IRIS were compared to non-IRIS controls using χ(2) and rank-sum tests and logistic regression. RESULTS TB-IRIS patients and controls had similar CD4 counts, levels of T-cell-associated immune activation, frequencies of T-cell memory subsets, and frequencies of interferon gamma (IFN-γ(+))/interleukin 2 (IL-2(+))/tumor necrosis factor alpha (TNF-α(+)) CD4(+) T-cells prior to ART initiation. After ART initiation, cellular immune activation and T-cell subsets also were similar in TB-IRIS patients and controls. In contrast, TB-IRIS patients had significantly greater early increases in the frequency of tuberculosis-specific polyfunctional IFN-γ(+)/IL-2(+)/TNF-α(+) CD4(+) T-cells on ART (P = .02); each quartile increase in the percentage of these cells was independently associated with a 2.8-fold increased risk of TB-IRIS (95% confidence interval, 1.1 to 7.5-fold). In a secondary analysis, patients with TB-IRIS had rapid, concomitant increases in tuberculosis-specific adaptive immune responses and interleukin 6 (IL-6) levels, whereas controls with similarly rapid increases in cellular immune function had IL-6 levels that tended to decrease on ART. CONCLUSIONS Rapid expansion of tuberculosis-specific polyfunctional CD4(+) T-cell responses, likely linked to increases in IL-6, is associated with development of paradoxical TB-IRIS.

Matrix Metalloproteinases in Tuberculosis-Immune Reconstitution Inflammatory Syndrome and Impaired Lung Function Among Advanced HIV/TB Co-infected Patients Initiating Antiretroviral Therapy

Background HIV-infected patients with pulmonary TB (pTB) can have worsening of respiratory symptoms as part of TB-immune reconstitution inflammatory syndrome (TB-IRIS) following antiretroviral therapy (ART) initiation. Thus, reconstitution of immune function on ART could drive incident lung damage in HIV/TB. Methods We hypothesized that increases in matrix metalloproteinases (MMPs), which can degrade lung matrix, on ART are associated with TB-IRIS among a cohort of advanced, ART naïve, HIV-infected adults with pTB. Furthermore, we related early changes in immune measures and MMPs on ART to lung function in an exploratory subset of patients post-TB cure. This study was nested within a prospective cohort study. Rank sum and chi-square tests, Spearmans correlation coefficient, and logistic regression were used for analyses. Results Increases in MMP-8 following ART initiation were independently associated with TB-IRIS (p = 0.04; adjusted odds ratio 1.5 [95% confidence interval: 1.0–2.1]; n = 32). Increases in CD4 counts and MMP-8 on ART were also associated with reduced forced expiratory volume in one-second post-TB treatment completion (r = − 0.7, p = 0.006 and r = − 0.6, p = 0.02, respectively; n = 14). Conclusions ART-induced MMP increases are associated with TB-IRIS and may affect lung function post-TB cure. End-organ damage due to TB-IRIS and mechanisms whereby immune restoration impairs lung function in pTB deserve further investigation.

Early emergence and selection of a SIV-LTR C/EBP site variant in SIV-infected macaques that increases virus infectivity.

CCAAT/enhancer binding protein (C/EBP)β, and C/EBP binding sites in the HIV/SIV- long terminal repeat (LTR) are crucial for regulating transcription and for IFNβ-mediated suppression of virus replication in macrophages, the predominant source of productive virus replication in the brain. We investigated sequence variation within the SIV-LTR C/EBP sites that may be under selective pressure in vivo and therefore associated with disease progression. Using the SIV-macaque model, we examined viral LTR sequences derived from the spleen, a site of macrophage and lymphocyte infection, and the brain from macaques euthanized at 10, 21, 42, 48 and 84 days postinoculation (p.i.). A dominant variant, DS1C/A, containing an adenine-to-guanine substitution and a linked cytosine-to-adenine substitution in the downstream (DS1) C/EBP site, was detected in the spleen at 10 days p.i. The DS1C/A genotype was not detected in the brain until 42 days p.i., after which it was the predominant replicating genotype in both brain and spleen. Functional characterization of the DS1C/A containing SIV showed increased infectivity with or without IFNβ treatment over the wild-type virus, SIV/17E-Fr. The DS1C/A C/EBP site had higher affinity for both protein isoforms of C/EBPβ compared to the wild-type DS1 C/EBP site. Cytokine expression in spleen compared to brain implicated IFNβ and IL-6 responses as part of the selective pressures contributing to emergence of the DS1C/A genotype in vivo. These studies demonstrate selective replication of virus containing the DS1C/A genotype that either emerges very early in spleen and spreads to the brain, or evolves independently in the brain when IFNβ and IL-6 levels are similar to that found in spleen earlier in infection.

Isoniazid clearance is impaired among human immunodeficiency virus/tuberculosis patients with high levels of immune activation

AIMS Immune activation, which is characteristic of both tuberculosis (TB) and human immunodeficiency virus (HIV) infection, is associated with impaired drug metabolism. We tested the hypothesis that elevated levels of systemic immune activation among adults with HIV/TB initiating antiretroviral therapy (ART) would be associated with impaired clearance of isoniazid. METHODS We conducted a prospective observational study of isoniazid pharmacokinetics (PK) and systemic immune activation prior to and 1 month after ART initiation. Nonlinear mixed effects analysis was performed to measure the covariate effect of immune activation on isoniazid clearance in a model that also included N‐acetyltransferase‐2 (NAT‐2) genotype and interoccasional variability on clearance (thereby analyzing the PK data before and after ART initiation in a single model). RESULTS We enrolled 40 patients in the PK visit prior to ART, and 24 patients returned for the second visit a median of 33 days after initiating antiretroviral therapy. The isoniazid concentration data were best described by a two‐compartment model with first‐order elimination. After accounting for NAT‐2 genotype, increasing levels of CD38 and HLA‐DR expression on CD8+ T cells (CD38+DR+CD8+) were associated with decreasing isoniazid clearance. CONCLUSION HIV/TB patients with high levels of immune activation demonstrated impaired isoniazid clearance. Future efforts should determine the role of this relationship in clinical hepatotoxicity events.

Isoniazid clearance is impaired among HIV/tuberculosis patients with high levels of immune activation

AIMS Immune activation, which is characteristic of both tuberculosis (TB) and human immunodeficiency virus (HIV) infection, is associated with impaired drug metabolism. We tested the hypothesis that elevated levels of systemic immune activation among adults with HIV/TB initiating antiretroviral therapy (ART) would be associated with impaired clearance of isoniazid. METHODS We conducted a prospective observational study of isoniazid pharmacokinetics (PK) and systemic immune activation prior to and 1 month after ART initiation. Nonlinear mixed effects analysis was performed to measure the covariate effect of immune activation on isoniazid clearance in a model that also included N‐acetyltransferase‐2 (NAT‐2) genotype and interoccasional variability on clearance (thereby analyzing the PK data before and after ART initiation in a single model). RESULTS We enrolled 40 patients in the PK visit prior to ART, and 24 patients returned for the second visit a median of 33 days after initiating antiretroviral therapy. The isoniazid concentration data were best described by a two‐compartment model with first‐order elimination. After accounting for NAT‐2 genotype, increasing levels of CD38 and HLA‐DR expression on CD8+ T cells (CD38+DR+CD8+) were associated with decreasing isoniazid clearance. CONCLUSION HIV/TB patients with high levels of immune activation demonstrated impaired isoniazid clearance. Future efforts should determine the role of this relationship in clinical hepatotoxicity events.

Outcomes in HIV-Infected Adults With Tuberculosis at Clinics With and Without Co-Located HIV Clinics in Botswana

SETTING Gaborone, Botswana. OBJECTIVE To determine if starting anti-tuberculosis treatment at clinics in Gaborone without co-located human immunodeficiency virus (HIV) clinics would delay time to highly active antiretroviral therapy (HAART) initiation and be associated with lower survival compared to starting anti-tuberculosis treatment at clinics with on-site HIV clinics. DESIGN Retrospective cohort study. Subjects were HAART-naïve, aged ≥ 21 years with pulmonary tuberculosis (TB), HIV and CD4 counts ≤ 250 cells/mm(3) initiating anti-tuberculosis treatment between 2005 and 2010. Survival at completion of anti-tuberculosis treatment or at 6 months post-treatment initiation and time to HAART after anti-tuberculosis treatment initiation were compared by clinic type. RESULTS Respectively 259 and 80 patients from clinics without and with on-site HIV facilities qualified for the study. Age, sex, CD4, baseline sputum smears and loss to follow-up rate were similar by clinic type. Mortality did not differ between clinics without or with on-site HIV clinics (20/250, 8.0% vs. 8/79, 10.1%, relative risk 0.79, 95%CI 0.36-1.72), nor did median time to HAART initiation (respectively 63 and 66 days, P = 0.53). CONCLUSION In urban areas where TB and HIV programs are separate, geographic co-location alone without further integration may not reduce mortality or time to HAART initiation among co-infected patients.

Common Variation in NLRP3 Is Associated With Early Death and Elevated Inflammasome Biomarkers Among Advanced HIV/TB Co-infected Patients in Botswana

Abstract Background Elevated inflammation is associated with early mortality among HIV/tuberculosis (TB) patients starting antiretroviral therapy (ART); however, the sources of immune activation are unclear. We hypothesized that common variation in innate immune genes contributes to excessive inflammation linked to death. As single nucleotide polymorphisms (SNPs) in inflammasome pathway genes can increase risk for inflammatory diseases, we investigated their association with early mortality among a previously described cohort of HIV/TB patients initiating ART in Botswana. Methods We genotyped 8 SNPs within 5 inflammasome pathway genes and determined their association with death. For adjusted analyses, we used a logistic regression model. For SNPs associated with mortality, we explored their relationship with levels of systemic inflammatory markers using a linear regression model. Results Ninety-four patients in the parent study had samples for genetic analysis. Of these, 82 (87%) were survivors and 12 (13%) died within 6 months of starting ART. In a logistic regression model, NLRP3 rs10754558 was independently associated with a 4.1-fold increased odds of death (95% confidence interval, 1.04–16.5). In adjusted linear regression models, the NLRP3 rs10754558-G allele was linked to elevated IL-18 at baseline (Beta, 0.23; SE, 0.10; P = .033) and week 4 post-ART (Beta, 0.24; SE, 0.11; P = .026). This allele was associated with increased MCP-1 at baseline (Beta, 0.24; SE, 0.10; P = .02) and IL-10 (Beta, 0.27; SE, 0.11; P = .013) at week 4 post-ART. Conclusion The NLRP3 rs10754558-G SNP is associated with an increased risk for early mortality in HIV/TB patients initiating ART. These patients may benefit from therapies that decrease inflammasome-mediated inflammation.