Alison L. Drake

Human NK cell repertoire diversity reflects immune experience and correlates with viral susceptibility

Human natural killer cell diversity is a metric of immune function associated with less effective antiviral response. The downside of diversity The adaptive immune system exemplifies the benefits of diversity, allowing for individual responses to specific pathogens. Natural killer (NK) cells are diverse at the single-cell level, but the contribution of this diversity to NK cell–mediated immunity has been unclear. Strauss-Albee et al. found that contrary to adaptive immune cells, human NK cell diversity is lower at birth than in adults. Moreover, diversification as a result of antiviral response decreases the flexibility of future antiviral responses. Indeed, high NK cell diversity was associated with increased risk of HIV-1 acquisition in African women. These data suggest that preexisting NK cell diversity should be considered in the context of viral infections. Innate natural killer (NK) cells are diverse at the single-cell level because of variegated expressions of activating and inhibitory receptors, yet the developmental roots and functional consequences of this diversity remain unknown. Because NK cells are critical for antiviral and antitumor responses, a better understanding of their diversity could lead to an improved ability to harness them therapeutically. We found that NK diversity is lower at birth than in adults. During an antiviral response to either HIV-1 or West Nile virus, NK diversity increases, resulting in terminal differentiation and cytokine production at the cost of cell division and degranulation. In African women matched for HIV-1 exposure risk, high NK diversity is associated with increased risk of HIV-1 acquisition. Existing diversity may therefore decrease the flexibility of the antiviral response. Collectively, the data reveal that human NK diversity is a previously undefined metric of immune history and function that may be clinically useful in forecasting the outcomes of infection and malignancy.

Herpes simplex virus type 2 and risk of intrapartum human immunodeficiency virus transmission.

OBJECTIVE: To determine whether herpes simplex virus type 2 (HSV-2) infection was associated with risk of intrapartum human immunodeficiency virus type 1 (HIV-1) transmission and to define correlates of HSV-2 infection among HIV-1-seropositive pregnant women. METHODS: We performed a nested case control study within a perinatal cohort in Nairobi, Kenya. Herpes simplex virus type 2 serostatus and the presence of genital ulcers were ascertained at 32 weeks of gestation. Maternal cervical and plasma HIV-1 RNA and cervical HSV DNA were measured at delivery. RESULTS: One hundred fifty-two (87%) of 175 HIV-1-infected mothers were HSV-2-seropositive. Among the 152 HSV-2-seropositive women, nine (6%) had genital ulcers at 32 weeks of gestation, and 13 (9%) were shedding HSV in cervical secretions. Genital ulcers were associated with increased plasma HIV-1 RNA levels (P=.02) and an increased risk of intrapartum HIV-1 transmission (16% of transmitters versus 3% of nontransmitters had ulcers; P = .003), an association which was maintained in multivariable analysis adjusting for plasma HIV-1 RNA levels (P=.04). We found a borderline association for higher plasma HIV-1 RNA among women shedding HSV (P=.07) and no association between cervical HSV shedding and either cervical HIV-1 RNA levels or intrapartum HIV-1 transmission (P=.04 and P=.05, respectively). CONCLUSION: Herpes simplex virus type 2 is the leading cause of genital ulcers among women in sub-Saharan Africa and was highly prevalent in this cohort of pregnant women receiving prophylactic zidovudine. After adjusting for plasma HIV-1 RNA levels, genital ulcers were associated with increased risk of intrapartum HIV-1 transmission. These data suggest that management of HSV-2 during pregnancy may enhance mother-to-child HIV-1 prevention efforts. LEVEL OF EVIDENCE: II

Impact of Prior HAART Use on Clinical Outcomes in a Large Kenyan HIV Treatment Program

BACKGROUND HIV treatment programs in Africa typically approach all enrolling patients uniformly. Growing numbers of patients are antiretroviral experienced. Defining patients on the basis of antiretroviral experience may inform enrollment practices, particularly if medical outcomes differ. METHODS Baseline and follow-up measures (CD4, weight change, and survival) were compared in a retrospective analysis between antiretroviral-naïve (ARV-N) and antiretroviral experience (ARV-E) patients enrolled at the Coptic Hope Center for Infectious Diseases in Nairobi, Kenya and followed between January 2004 and August 2006. RESULTS 1,307 ARV-N and 962 ARV-E patients receiving highly active antiretroviral therapy (HAART) were followed for median of 9 months (interquartile range: 4-16 months). Compared to ARV-N, ARV-E had substantially higher CD4 count (median cells/mm(3), 193 versus 95, P < 0.001) and weight (median kg, 62 versus 57, P < 0.001) at baseline, and lower rates of change in CD4 (-9.2 cells/mm(3)/month; 95% CI, -11.4 -7.0) and weight (-0.24 kg/month; 95% CI, -0.35 - -0.14) over 12 months. Mortality was significantly higher in ARV-N than ARV-E (P = 0.001). CONCLUSIONS ARV-E patients form a growing group that differs significantly from ARV-N patients and requires a distinct approach from ARV-N clients. Systematic approaches to streamline care of ARV-E patients may allow focused attention on early ARV-N clients whose mortality risks are substantially higher.

Compartmentalized Cytomegalovirus Replication and Transmission in the Setting of Maternal HIV-1 Infection

BACKGROUND Cytomegalovirus (CMV) infection is associated with adverse outcomes in human immunodeficiency virus (HIV)-exposed infants. Determinants of vertical CMV transmission in the setting of maternal HIV-1 infection are not well-defined. METHODS CMV and HIV-1 levels were measured in plasma, cervical secretions, and breast milk of 147 HIV-1-infected women to define correlates of maternal CMV replication and infant CMV acquisition. RESULTS Although few women had detectable CMV in plasma (4.8%), the majority had detectable CMV DNA in cervical secretions (66%) and breast milk (99%). There was a strong association between cervical CMV detection during pregnancy and later breast milk levels (β = 0.47; P = .005). Plasma HIV-1 level and CD4 counts were associated with CMV in the cervix and breast milk. However HIV-1 levels within the cervix and breast milk were not associated with CMV within these compartments. Maternal breast milk CMV levels (hazard ratio [HR], 1.4; P = .003) and maternal CD4 < 450 cells/mm(3) (HR, 1.8; P = .008) were independently associated with infant CMV acquisition; each log10 increase in breast milk CMV was associated with a 40% increase in infant infection. The breast milk CMV level required to attain a 50% probability of CMV transmission increased with higher maternal CD4 counts, increasing from 3.55 log10 CMV DNA copies/mL at a CD4 count of 350 cells/mm(3) to 5.50 log10 CMV DNA copies/mL at a CD4 count of 1000 cells/mm(3). CONCLUSIONS Breast milk CMV levels and maternal CD4 count are major determinants of CMV transmission in the setting of maternal HIV-1. Maternal immune reconstitution or lowering breast milk CMV levels may reduce vertical CMV transmission.

HIV acquisition during pregnancy and postpartum is associated with genital infections and partnership characteristics

Objective:The objective of this study is to determine the risk and cofactors for HIV acquisition during pregnancy and postpartum. Design:A prospective cohort study Methods:Pregnant women in western Kenya were enrolled if HIV seronegative at that visit or within 3 months. Serial HIV nucleic acid amplification tests (NAATs) were conducted at 1 to 3-month intervals to 9 months postpartum. Genital swabs were collected for detection of chlamydia and gonorrhoea at baseline, and for trichomonas, bacterial vaginosis and yeast at baseline and follow-up. Results:Among 1304 pregnant women, median age was 22 years, 78% were married for a median of 4 years, 66% reported knowing partner HIV status and 8% reported using condoms. Study retention was 98%. During 1235 person-years of follow-up, HIV incidence was 2.31/100 person-years [95% confidence interval (95% CI) 0.71–4.10]. Incident HIV was associated with syphilis (hazard ratio 9.18, 95% CI 2.15–39.3), chlamydia (hazard ratio 4.49, 95% CI 1.34–15.0), bacterial vaginosis (hazard ratio 2.91, 95% CI 1.25–6.76), yeast (hazard ratio 3.46, 95% CI 1.46–8.19), sexually transmitted infection (STI) history (hazard ratio 3.48, 95% CI 1.31–9.27), lifetime number of sex partners (hazard ratio 1.19, 95% CI 1.03–1.37), partner age discordance (hazard ratio 1.07 per year, 95% CI 1.02–1.13) and shorter marriage (hazard ratio 1.19 per year, 95% CI 1.03–1.38). No women with incident HIV reported an HIV-infected partner. In multivariate analyses, chlamydia, older partners and yeast infection remained significant; however, power was limited. Conclusion:Pregnant and lactating women may not perceive HIV risk and rarely used condoms. Prevention and treatment of genital infections and risk stratification to identify women for pre-exposure prophylaxis (PrEP) could decrease HIV acquisition in pregnant/lactating women.

Pregnant Women and Disclosure to Sexual Partners After Testing HIV-1–Seropositive During Antenatal Care

In African countries highly affected by human immunodeficiency virus-1 (HIV-1) women are more likely to be tested for HIV-1 than men due to scale-up of antenatal testing programs to prevent mother-to-child transmission (PMTCT) of HIV-1. As part of standard post-test counseling HIV-1 seropositive women are advices to disclose their status to their partners and refer them for testing. Disclosure to male partners antenatally has been associated with improved adherence to prevention of PMTCT regimens better infant feeding practices safer sex practices and increase male partner testing. Despite these findings promotion of male partner disclosure is not a central component of most PMTCT programs. While barriers to female-to-male disclosure are well-described and include socio-economic vulnerability fear of violence of abandonment and family stigma little has been published describing how to promote disclosure to male partners after antenatal testing. This study followed Kenyan HIV-1 – seropositive women enrolled in a randomized clinical trial of herpes suppression during pregnancy until 1 year postpartum to determine disclosure rates and to assess timing and correlates of disclosure. Our hypothesis was that women who were counseled and supported to disclose their HIV-1 status as part of a longitudinal research study would over time be more likely to disclose to partners. There is clear evidence that promoting disclosure to partners in the antenatal setting can lead to both individual and public health benefits but little is known about how to achieve this goal. The research indicates that rather than focusing on strategies that focus on strategies that promote disclosure by women such as counseling there should be an emphasis on strategies that make HIV-1 testing more appealing to men in this setting such as shifts in infrastructure promoting ease and availability of testing and reduction of stigma and barriers to male partner HIV-1 testing and treatment. In conclusion the research shows that mothers diagnosed with HIV-1 antenatally face challenges in disclosing to their male partners.

Valacyclovir Suppressive Therapy Reduces Plasma and Breast Milk HIV-1 RNA Levels During Pregnancy and Postpartum: A Randomized Trial

BACKGROUND The effect of herpes simplex virus type 2 (HSV-2) suppression on human immunodeficiency virus type 1 (HIV-1) RNA in the context of prevention of mother-to-child transmission (PMTCT) interventions is unknown. METHODS Between April 2008 and August 2010, we conducted a randomized, double-blind trial of twice daily 500 mg valacyclovir or placebo beginning at 34 weeks gestation in 148 HIV-1/HSV-2 coinfected pregnant Kenyan women ineligible for highly active antiretroviral therapy (CD4 > 250 cells/mm(3)). Women received zidovudine and single dose nevirapine for PMTCT and were followed until 12 months postpartum. RESULTS Mean baseline plasma HIV-1 RNA was 3.88 log(10) copies/mL. Mean plasma HIV-1 was lower during pregnancy (-.56 log(10) copies/mL; 95% confidence interval [CI], -.77 to -.34) and after 6 weeks postpartum (-.51 log(10) copies/mL; 95% CI, -.73 to -.30) in the valacyclovir arm than the placebo arm. Valacyclovir reduced breast milk HIV-1 RNA detection at 6 and 14 weeks postpartum compared with placebo (30% lower, P = .04; 46% lower, P = .01, respectively), but not after 14 weeks. Cervical HIV-1 RNA detection was similar between arms (P = .91). CONCLUSIONS Valacyclovir significantly decreased early breast milk and plasma HIV-1 RNA among women receiving PMTCT. CLINICAL TRIALS REGISTRATION NCT00530777.

Maternal Valacyclovir and Infant Cytomegalovirus Acquisition A Randomized Controlled Trial among HIV-Infected Women

Background Studies in HIV-1-infected infants and HIV-1-exposed, uninfected infants link early cytomegalovirus (CMV) acquisition with growth delay and cognitive impairment. We investigated maternal valacyclovir to delay infant acquisition of CMV. Methods Pregnant women with HIV-1, HSV-2 and CD4 count >250 cells/µl were randomized at 34 weeks gestation to 500 mg twice-daily valacyclovir or placebo for 12 months. Maternal CMV DNA was measured in plasma at 34 weeks gestation, in cervical secretions at 34 and 38 weeks gestation, and in breast milk at 7 postpartum timepoints; infant CMV DNA was measured in dried blood spots at 8 timepoints including birth. Results Among 148 women, 141 infants were compared in intent-to-treat analyses. Maternal and infant characteristics were similar between study arms. Infant CMV acquisition did not differ between study arms, with 46/70 infants (66%) in placebo arm and 47/71 infants (66%) in the valacyclovir arm acquiring CMV; median time to CMV detection did not differ. CMV DNA was detected in 92% of 542 breast milk specimens with no difference in CMV level between study arms. Change in cervical shedding of CMV DNA between baseline and 38 weeks was 0.40-log greater in the placebo arm than the valacyclovir arm (p = 0.05). Conclusions In this cohort of HIV-1-seropositive mothers, two-thirds of infants acquired CMV by one year. Maternal valacyclovir had no effect on timing of infant CMV acquisition or breast milk CMV viral loads, although it modestly reduced cervical CMV shedding. Maternal prophylaxis to reduce infant CMV acquisition warrants further evaluation in trials with antiviral agents. Trials Registration ClinicalTrials.gov NCT00530777

Infant safety during and after maternal valacyclovir therapy in conjunction with antiretroviral HIV-1 prophylaxis in a randomized clinical trial.

Background Maternal administration of the acyclovir prodrug valacyclovir is compatible with pregnancy and breastfeeding. However, the safety profile of prolonged infant and maternal exposure to acyclovir in the context of antiretrovirals (ARVs) for prevention of mother-to-child HIV-1 transmission (PMTCT) has not been described. Methods Pregnant Kenyan women co-infected with HIV-1/HSV-2 with CD4 counts > 250 cells/mm3 were enrolled at 34 weeks gestation and randomized to twice daily 500 mg valacyclovir or placebo until 12 months postpartum. Women received zidovudine from 28 weeks gestation and single dose nevirapine was given to women and infants at the time of delivery for PMTCT. Infant blood was collected at 6 weeks for creatinine and ALT. Breast milk specimens were collected at 2 weeks postpartum from 71 women in the valacyclovir arm; acyclovir levels were determined for a random sample of 44 (62%) specimens. Fisher’s Exact and Wilcoxon rank-sum tests were used for analysis. Results One hundred forty-eight women were randomized and 146 mother-infant pairs were followed postpartum. PMTCT ARVs were administered to 98% of infants and all mothers. Valacyclovir was not associated with infant or maternal toxicities or adverse events, and no congenital malformations were observed. Infant creatinine levels were all normal (< 0.83 mg/dl) and median creatinine (median 0.50 mg/dl) and infant growth did not differ between study arms. Acyclovir was detected in 35 (80%) of 44 breast milk samples collected at 2 weeks postpartum. Median and maximum acyclovir levels were 2.62 and 10.15 mg/ml, respectively (interquartile range 0.6–4.19). Conclusions Exposure to PMTCT ARVs and acyclovir after maternal administration of valacyclovir during pregnancy and postpartum to women co-infected with HIV-1/HSV-2 was not associated with an increase in infant or maternal toxicities or adverse events. Trial Registration ClinicalTrials.gov NCT00530777

Herpes Simplex Virus Type 2, Genital Ulcers and HIV-1 Disease Progression in Postpartum Women

Background Co-infection with herpes simplex virus type 2 (HSV-2) has been associated with increased HIV-1 RNA levels and immune activation, two predictors of HIV-1 progression. The impact of HSV-2 on clinical outcomes among HIV-1 infected pregnant women is unclear. Methods HIV-1 infected pregnant women in Nairobi were enrolled antenatally and HSV-2 serology was obtained. HIV-1 RNA and CD4 count were serially measured for 12–24 months postpartum. Survival analysis using endpoints of death, opportunistic infection (OI), and CD4<200 cells µL, and linear mixed models estimating rate of change of HIV-1 RNA and CD4, were used to determine associations between HSV-2 serostatus and HIV-1 progression. Results Among 296 women, 254 (86%) were HSV-2-seropositive. Only 30 (10%) women had prior or current genital ulcer disease (GUD); median baseline CD4 count was 422 cells µL. Adjusting for baseline CD4, women with GUD were significantly more likely to have incident OIs (adjusted hazard ratio (aHR) 2.79, 95% CI: 1.33–5.85), and there was a trend for association between HSV-2-seropositivity and incident OIs (aHR 3.83, 95% CI: 0.93–15.83). Rate of change in CD4 count and HIV-1 RNA did not differ by HSV-2 status or GUD, despite a trend toward higher baseline HIV-1 RNA in HSV-2-seropositive women (4.73 log10 copies/ml vs. 4.47 log10 copies/ml, P = 0.07). Conclusions HSV-2 was highly prevalent and pregnant HIV-1 infected women with GUD were significantly more likely to have incident OIs than women without GUD, suggesting that clinically evident HSV-2 is a more important predictor of HIV-1 disease progression than asymptomatic HSV-2.