Background We evaluated the prognostic utility of interferon-gamma release assays (IGRAs) for active tuberculosis (TB) and mortality in Kenyan HIV-1 infected women and their infants. Methods Prevalence and correlates of Mycobacterium tuberculosis-specific T-SPOT.TB IGRA positivity were determined during pregnancy in a historical cohort of HIV-1 infected women. Hazard ratios, adjusted for baseline maternal CD4 count (aHRCD4) were calculated for associations between IGRA positivity and risk of active TB and mortality over 2-year postpartum follow-up in women and their infants. Results Of 333 women tested, 52 (15.6%) had indeterminate IGRAs. Of the remaining 281 women, 120 (42.7%) had positive IGRAs, which were associated with a 4.5-fold increased risk of active TB [aHRCD4: 4.5; 95% confidence interval (CI): 1.1–18.0; p=0.03]. Among immunosuppresed women (CD4<250 cell/mm3), positive IGRAs were associated with increased risk of maternal mortality (aHRCD4: 3.5; 95% CI: 1.02–12.1; p=0.045), maternal active TB or mortality (aHRCD4: 5.2; 95% CI: 1.7–15.6; p=0.004) and infant active TB or mortality, overall (aHRCD4: 3.0; 95% CI: 1.0–8.9; p= 0.05) and in HIV-1 exposed uninfected infants (aHRCD4: 7.3; 95% CI: 1.6–33.5; p =0.01). Conclusions Positive IGRAs in HIV-1 infected pregnant women were associated with postpartum active TB and mortality in mothers and their infants.

Background Breast-feeding by infants exposed to human immunodeficiency virus type 1 (HIV-1) provides an opportunity to assess the role played by repeated HIV-1 exposure in eliciting HIV-1–specific immunity and in defining whether immune responses correlate with protection from infection. Methods Breast-feeding infants born to HIV-1–seropositive women were assessed for HLA-selected HIV-1 peptide–specific cytotoxic T lymphocyte interferon (IFN)–γ responses by means of enzyme-linked immunospot (ELISpot) assays at 1, 3, 6, 9, and 12 months of age. Responses were deemed to be positive when they reached ⩾50 HIV-1–specific sfu/1 × 106 peripheral blood mononuclear cells (PBMCs) and were at least twice those of negative controls. Results A total of 807 ELISpot assays were performed for 217 infants who remained uninfected with HIV-1 at ∼12 months of age; 101 infants (47%) had at least 1 positive ELISpot result (median, 78–170 sfu/1 × 106 PBMCs). The prevalence and magnitude of responses increased with age (P = .01 and P = .007, respectively); the median log10 value for HIV-1–specific IFN-γ responses increased by 1.0 sfu/1 × 106 PBMCs/month (P < .001) between 1 and 12 months of age. Of 141 HIV-1–uninfected infants with 1-month ELISpot results, 10 (7%) acquired HIV-1 infection (0/16 with positive vs. 10/125 [8%] with negative ELISpot results; P = .6). Higher values for log10 HIV-1–specific spot-forming units at 1 month of age were associated with a decreased risk of HIV-1 infection, adjusted for maternal HIV-1 RNA level (adjusted hazard ratio, 0.09 [95% confidence interval, 0.01–0.72]). Conclusions Breast-feeding HIV-1–exposed uninfected infants frequently had HIV-1–specific IFN-γ responses. Greater early HIV-1–specific IFN-γ responses were associated with decreased HIV-1 acquisition.

Background There is limited information regarding the pattern and correlates of viral replication in vertically HIV-1–infected children and its role on their outcomes in resource-limited settings. Methods HIV-1–infected infants were followed from birth to 24 months. Serial HIV-1 RNA levels were compared in infants infected in utero (<48 hours), peripartum (48 hours–1 month), and late postnatal (after 1 month). Cofactors for viral peak [highest viral load (VL) within 6 months of infection] and set point and mortality were determined. Results Among 85 HIV-1–infected infants, 24 were infected in utero, 41 peripartum, 13 late postnatal; 7 had no 48-hour assay. HIV-1 VL set point was significantly lower in infants infected >1 month vs. ≤1 month (5.59 vs. 6.24 log10 copies per milliliter, P = 0.01). Maternal VL correlated with peak infant VL (P < 0.001). Univariately, infant peak and set point VL and 6-month CD4% <15% predicted mortality; and 6-month CD4% <15% remained independently predictive in multivariate analyses (hazard ratio = 4.85, 95% confidence interval: 1.90 to 12.36). Conclusions Infants infected after the age of 1 month contained virus better than infants infected before 1 month of age. Maternal VL predicted infant VL, which, in turn was associated with early mortality.

Background HIV exposed seronegative (HESN) women represent the population most in need of a prophylactic antiviral strategy. Mucosal cationic polypeptides can potentially be regulated for this purpose and we here aimed to determine their endogenous expression and HIV neutralizing activity in genital secretions of women at risk of HIV infection. Methodology/Principal Findings Cervicovaginal secretions (CVS) of Kenyan women in HIV-serodiscordant relationships (HESN, n = 164; HIV seropositive, n = 60) and low-risk controls (n = 72) were assessed for the cationic polypeptides HNP1–3, LL-37 and SLPI by ELISA and for HIV neutralizing activity by a PBMC-based assay using an HIV primary isolate. Median levels of HNP1–3 and LL-37 in CVS were similar across study groups. Neither HSV-2 serostatus, nor presence of bacterial vaginosis, correlated with levels of HNP1–3 or LL-37 in the HESN women. However, an association with their partner's viral load was observed. High viral load (>10,000 HIV RNA copies/ml plasma) correlated with higher levels of HNP1–3 and LL-37 (p = 0.04 and 0.03, respectively). SLPI was most abundant in the low-risk group and did not correlate with male partner's viral load in the HESN women. HIV neutralizing activity was found in CVS of all study groups. In experimental studies, selective depletion of cationic polypeptides from CVS rendered the remaining CVS fraction non-neutralizing, whereas the cationic polypeptide fraction retained the activity. Furthermore, recombinant HNP1–3 and LL-37 could induce neutralizing activity when added to CVS lacking intrinsic activity. Conclusions/Significance These findings show that CVS from HESN, low-risk, and HIV seropositive women contain HIV neutralizing activity. Although several innate immune proteins, including HNP1–3 and LL-37, contribute to this activity these molecules can also have inflammatory properties. This balance is influenced by hormonal and environmental factors and in the present HIV serodiscordant couple cohort study we show that a partner's viral load is associated with levels of such molecules.

Antiretroviral therapy-naive HIV-1 infected infants experience poor viral containment and rapid disease progression compared to adults. Viral factors (e.g. transmitted cytotoxic T- lymphocyte (CTL) escape mutations) or infant factors (e.g. reduced CTL functional capacity) may explain this observation. We assessed CTL functionality by analysing selection in CTL-targeted HIV-1 epitopes following perinatal infection. HIV-1 gag, pol and nef sequences were generated from a historical repository of longitudinal specimens from 19 vertically infected infants. Evolutionary rate and selection were estimated for each gene and in CTL-restricted and non-restricted epitopes. Evolutionary rate was higher in nef and gag vs. pol, and lower in infants with non-severe immunosuppression vs. severe immunosuppression across gag and nef. Selection pressure was stronger in infants with non-severe immunosuppression vs. severe immunosuppression across gag. The analysis also showed that infants with non-severe immunosuppression had stronger selection in CTL-restricted vs. non-restricted epitopes in gag and nef. Evidence of stronger CTL selection was absent in infants with severe immunosuppression. These data indicate that infant CTLs can exert selection pressure on gag and nef epitopes in early infection and that stronger selection across CTL epitopes is associated with favourable clinical outcomes. These results have implications for the development of paediatric HIV-1 vaccines.

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With the expansion of global strategies to prevent mother to child transmission of HIV, the number of perinatal HIV infections had dropped dramatically. This public health achievement has created a population of HIV exposed but uninfected (HEU) infants with substantially more morbidity and mortality than their HIV unexposed (HU) peers. We hypothesize that in utero exposure to maternal HIV induces a premature activation and expansion of fetal T cells, potentially leading to infant immune dysregulation (Th1 polarization/immune exhaustion) upon exposure to pathogens after birth. We selected pre-ARV era cord blood samples from 17 HEU infants born to viremic Kenyan women and 17 cord blood samples from HIV unexposed infants born to Kenyan women with similar sociodemographics. Next generation technology including addition of unique molecular identifiers was used to generate amplicon libraries for sequencing (MiSeq, Illumina). We calculated the Simpson Diversity Index for the 100 most frequent clones per TRB family. The median Ds for HU cord blood samples was 0.1, representing near maximal diversity of the TCR repertoire. Overall, HEU samples displayed a 30% reduction in diversity compared to the samples from HU infants, indicative of fetal T cell clonal expansion. Of note, the median diversity of Kenyan HEU samples located closer to the diversity of American adult peripheral blood than to the diversity of American cord blood. Although the antigen specificity of these cells is unknown, these results support the hypothesis that HIV exposure in utero stimulates fetal immune responses and point towards the existence of specific features of the immune system of newborn HEU infants which might be linked to their poor morbidity and mortality rates.