Relationship between markers of HIV-1 disease progression and serum β-carotene concentrations in Kenyan women

Observational studies have suggested that low serum β-carotene concentrations may influence HIV-1 disease progression. However, randomized trials have not demonstrated beneficial effects of β-carotene supplementation. To understand this discrepancy, we conducted a cross-sectional study among 400 HIV-1-seropositive women in Mombasa, Kenya, to correlate serum β-carotene concentrations with several measures of HIV-1 disease severity. β-Carotene concentrations were significantly associated with biologic markers of HIV-1 disease progression (CD4 count, HIV-1 plasma viral load, serum C-reactive protein [CRP] concentration, and serum albumin level). In multivariate analysis, β-carotene concentrations below the median were associated with elevated CRP (>10mg/l, adjusted odds ratio [aOR] 3.32, 95% confidence interval [CI] 1.99–5.53, P <0.001) and higher HIV-1 plasma viral load (for each log10 copies/mL increase, aOR 1.38, 95% CI 1.01–1.88, P = 0.04). In the context of negative findings from randomized trials of β-carotene supplementation in HIV-1-seropositive individuals, these results suggest that low β-carotene concentrations primarily reflect more active HIV-1 infection rather than a deficiency amenable to intervention.

Serologic testing algorithm for recent HIV seroconversion in estimating incidence of HIV-1 among adults visiting a VCT centre at a Kenyan tertiary health institution

OBJECTIVE

To determine HIV high risk groups among adults visiting Kenyatta National Hospital Voluntary Counselling and Testing Centre by use of Serologic Testing Algorithm for Recent HIV Seroconversion (STARHS).

DESIGN

A cross-sectional study of adults.

SETTING

Kenyatta National Hospital Voluntary and Counselling Centre.

RESULTS

Of the 6,415 adults screened for antibodies to HIV at Kenyatta National Hospital VCT Centre between July 2002 and February 2003, 728 tested positive in the two HIV screening tests used at the center, indicating a prevalence of 11%. Of these seropositive cases, 355 consented to participate in the study. Using STARHS, 34 (9.6%) of the plasma samples were classified as being from individuals with recent infection (within 170 days), giving an annual estimated HIV-1 incidence in this population of 1.3 infections per 100 person-years with a 95% CI of 0.872-1.728%. Young adults had a higher rate of new infection than older adults. Young females were infected much earlier in life, with a peak age of new infections of 26 years, versus 31 years for young males.

CONCLUSION

This study confirms our hypothesis that STARHS or Detuned assay can be used to determine HIV incidence in this population. The HIV high risk groups as identified by this study are young women between ages 16 to 26 years old and men between ages 45 to 55 years of age.

Prevalent herpes simplex virus type 2 infection is associated with altered vaginal flora and an increased susceptibility to multiple sexually transmitted infections

BACKGROUND

Prevalent herpes simplex virus type 2 (HSV-2) infection increases human immunodeficiency virus acquisition. We hypothesized that HSV-2 infection might also predispose individuals to acquire other common sexually transmitted infections (STIs).

METHODS

We studied the association between prevalent HSV-2 infection and STI incidence in a prospective, randomized trial of periodic STI therapy among Kenyan female sex workers. Participants were screened monthly for infection with Neisseria gonorrhoeae and Chlamydia trachomatis, and at least every 6 months for bacterial vaginosis (BV) and infection with Treponema pallidum, Trichomonas vaginalis, and/or HSV-2.

RESULTS

Increased prevalence of HSV-2 infection and increased prevalence of BV were each associated with the other; the direction of causality could not be determined. After stratifying for sexual risk-taking, BV status, and antibiotic use, prevalent HSV-2 infection remained associated with an increased incidence of infection with N. gonorrhoeae (incidence rate ratio [IRR], 4.3 [95% confidence interval {CI}, 1.5-12.2]), T. vaginalis (IRR, 2.3 [95% CI, 1.3-4.2]), and syphilis (IRR, 4.7 [95% CI, 1.1-19.9]). BV was associated with increased rates of infection with C. trachomatis (IRR, 2.1 [95% CI, 1.1-3.8]) and T. vaginalis (IRR, 8.0 [95% CI, 3.2-19.8]). CONCLUSION; Increased prevalences of HSV-2 infection and BV were associated with each other and also associated with enhanced susceptibility to an overlapping spectrum of other STIs. Demonstration of causality will require clinical trials that suppress HSV-2 infection, BV, or both.

Sustained changes in sexual behavior by female sex workers after completion of a randomized HIV prevention trial

INTRODUCTION

Behavioral interventions in female sex workers (FSWs) are associated with changes in sexual behavior and reduced rates of sexually transmitted infections (STIs) and HIV We examined the sustainability of such interventions.

METHODS

HIV-uninfected Kenyan FSWs were enrolled in a clinical trial that provided free male condoms, community and clinic-based counseling, and STI management. After trial completion, scaled-back community-based resources remained in place. More than a year later, women were invited to complete a follow-up behavioral questionnaire and to undergo STI/HIV counseling and testing. Individual changes in sexual behavior were assessed by paired analysis.

RESULTS

One hundred seventy-two women participated in the resurvey 1.2 years after trial termination. Client numbers had risen (paired t test, P < 0.001), but condom use had also increased (P < 0.001); both remained substantially lower than at enrollment. Regular partners accounted for a greater proportion of unprotected FSW sexual encounters (35% vs. 10%; P < 0.001). Only 9 (5.2%) of 172 women had a conventional STI, and the follow-up HIV incidence of 1.6 per 100 person-years (PYs) was similar to that during the trial period (3.7 per 100 PYs). Incident STIs and HIV were associated with the frequency of unprotected sex and younger age.

CONCLUSIONS

Less intensive community-based risk reduction services after clinical trial termination may support ongoing reductions in STIs and HIV among high-risk FSWs.

Strong TCR Conservation and Altered T Cell Cross-Reactivity Characterize a B*57-Restricted Immune Response in HIV-1 Infection

HLA-B*57 is associated with slower disease progression to AIDS, and CD8+ T cell responses to B*57-restricted epitopes are thought to contribute to this protective effect. In this study, we evaluate the B*57-restricted p24 KAFSPEVIPMF (KF11) immune response which is immunodominant during chronic infection. Previously, we observed that the KF11 clade variants KGFNPEVIPMF [A2G,S4N] and KAFNPEIIMPF [S4N,V7I], sharing a position 4 mutation, are differentially recognized by KF11-specific T cells. By combining structural and cellular studies, we now demonstrate that the KF11 and [A2G,S4N] epitopes induce distinct functional responses in [A2G,S4N] and KF11-specific T cells, respectively, despite minimal structural differences between the individual B*57-peptide complexes. Recently, we also elucidated the highly distinct structure of KF11 in complex with B*5703, and have now characterized the CD8+ T cell repertoire recognizing this epitope. We now report striking features of TCR conservation both in terms of TCR Valpha and Vbeta chain usage, and throughout the hypervariable region. Collectively, our findings highlight unusual features of the B*5701/B*5703-KF11-specific immune responses which could influence disease progression and that might be important to consider when designing future vaccine regimens.

HIV-1 infection alters the retinol-binding protein:transthyretin ratio even in the absence of the acute phase response

The ratio of retinol-binding protein (RBP) to transthyretin (TTR) has been proposed as an indirect method with which to assess vitamin A status in the context of inflammation. Few studies have been conducted among adults, and none examined the effect of HIV-1 infection. Our goal was to assess the RBP:TTR ratio among adults, including the effects of HIV-1 and the acute phase response. We used data from a cross-sectional study of 600 Kenyan women, of whom 400 had HIV-1. The effect of vitamin A supplementation among the HIV-1-infected participants was subsequently assessed in a randomized trial. Among HIV-1-uninfected women without an acute phase response, a RBP:TTR cut-off value of 0.25 had approximately 80% sensitivity and specificity to detect vitamin A deficiency (retinol <0.70 micromol/L). No RBP:TTR cut-off value demonstrated both high sensitivity and specificity among HIV-1 infected women without evidence of inflammation. HIV-1 infection and advanced HIV-1 disease were associated with higher RBP:TTR ratios. The effect of HIV-1 was independent of the acute phase response, which also increased the RBP:TTR ratio. Serum retinol increased with vitamin A supplementation among those with a low RBP:TTR ratio, although the effect was small and was not present among those with concurrent inflammation. Thus, the RBP:TTR ratio has modest ability to predict vitamin A deficiency among healthy adults, but HIV-1 infection alters the ratio, even in the absence of the acute phase response. Our results raise questions about the utility of this measurement given the high prevalence of HIV-1 infection in areas where vitamin A deficiency is common.

Identification of a novel HLA B*57 restricted cytotoxic T-lymphocyte epitope within HIV-1 rev

HLA-B5701 and its related allele B5703 have been shown to be strongly associated with slow HIV-1 disease progression. To elucidate the effect of these alleles fully on disease progression it is essential to identify key HIV-1 epitopes that are restricted by these alleles. Here we describe the identification of a novel HLA-B5701, B5703 restricted epitope within HIV-1 rev, which accounted for up to 25 and 40% of the total cytotoxic T-lymphocyte responses in two patients.

Associations of sexual risk taking among Kenyan female sex workers after enrollment in an HIV-1 prevention trial

BACKGROUND

Female sex workers (FSWs) often lack the ability to negotiate safer sex and are at high risk for HIV-1 infection and sexually transmitted infections (STIs).

METHODS

Seronegative FSWs were enrolled in an STI/HIV-1 prevention trial in Nairobi, Kenya. Demographics and sexual risk taking were assessed every 3 months. Predictors of reduced risk taking were defined using multivariate logistic regression.

RESULTS

Four hundred sixty-six FSWs were enrolled and followed for just over 2 years each. A spectrum of sex work was apparent: FSWs working in night clubs were younger, charged more for sex, and used condoms more frequently; FSWs working from home were older, charged less, and used condoms the least; and those working in bars were intermediate. Increases in reported condom use were most significant and sustained for FSWs working from home and charging less for sex and were poorly maintained for bar-based FSWs. Self-reported lower condom use, higher client numbers, and alcohol use were associated with higher STI rates.

CONCLUSIONS

Home-based FSWs and those charging less for sex used condoms the least at baseline but showed the greatest and most sustained improvements over time. Potential response heterogeneity in FSW subgroups should be considered in the design of HIV-1 prevention programs.

Female‐to‐Male Infectivity of HIV‐1 among Circumcised and Uncircumcised Kenyan Men

BACKGROUND

A lack of male circumcision has been associated with increased risk of human immunodeficiency virus type 1 (HIV-1) acquisition in a number of studies, but questions remain as to whether confounding by behavioral practices explains these results. The objective of the present study was to model per-sex act probabilities of female-to-male HIV-1 transmission (i.e., infectivity) for circumcised and uncircumcised men, by use of detailed accounts of sexual behavior in a population with multiple partnerships.

METHODS

Data were collected as part of a prospective cohort study of HIV-1 acquisition among 745 Kenyan truck drivers. Sexual behavior with wives, casual partners, and prostitutes was recorded at quarterly follow-up visits. Published HIV-1 seroprevalence estimates among Kenyan women were used to model HIV-1 per-sex act transmission probabilities.

RESULTS

The overall probability of HIV-1 acquisition per sex act was 0.0063 (95% confidence interval, 0.0035-0.0091). Female-to-male infectivity was significantly higher for uncircumcised men than for circumcised men (0.0128 vs. 0.0051; P=.04). The effect of circumcision was robust in subgroup analyses and across a wide range of HIV-1 prevalence estimates for sex partners.

CONCLUSIONS

After accounting for sexual behavior, we found that uncircumcised men were at a >2-fold increased risk of acquiring HIV-1 per sex act, compared with circumcised men. Moreover, female-to-male infectivity of HIV-1 in the context of multiple partnerships may be considerably higher than that estimated from studies of HIV-1-serodiscordant couples. These results may explain the rapid spread of the HIV-1 epidemic in settings, found throughout much of Africa, in which multiple partnerships and a lack of male circumcision are common.

Micronutrient Supplementation Increases Genital Tract Shedding of HIV-1 in Women

To test the hypothesis that micronutrient supplementation decreases genital HIV-1 shedding, a double-blind, randomized, placebo-controlled trial of 6 weeks of multivitamin plus selenium supplementation vs. placebo was conducted among 400 HIV-1-seropositive, nonpregnant, antiretroviral-naive women in Mombasa, Kenya. Primary outcome measures included cervical and vaginal shedding of HIV-1-infected cells and RNA. Secondary outcomes included plasma viral load and CD4 count. Surprisingly, the odds of detection of vaginal HIV-1-infected cells were 2.5-fold higher (P = 0.001) and the quantity of HIV-1 RNA in vaginal secretions was 0.37 log10 copies/swab higher (P = 0.004) among women who received micronutrients in comparison to placebo, even after adjustment for potential confounders including baseline HIV-1 shedding and CD4 count. The increase in vaginal HIV-1 shedding was greatest among women who had normal baseline selenium levels. Micronutrient supplementation resulted in higher CD4 (+23 cells/microL, P = 0.03) and CD8 (+74 cells/microL, P = 0.005) counts compared with placebo but did not alter the plasma viral load. In this randomized trial, micronutrients resulted in higher levels of genital HIV-1 shedding compared with placebo. The potential benefit of micronutrient supplementation in HIV-1-seropositive women should be considered in relation to the potential for increased infectivity.

HIV-1 Env-specific cytotoxic T-lymphocyte responses in exposed, uninfected Kenyan sex workers: a prospective analysis

The prospective significance of HIV-specific cytotoxic T lymphocyte (CTL) responses in highly exposed, persistently seronegative populations is unknown. In 1996-1997 we screened for CTL responses against HIV clade B Env in 39 recently enrolled Kenyan female sex workers, and followed these women prospectively. Annual HIV incidence was 5.8%. CTL were independently associated with age and recent HIV-1 exposure,but were not prospectively associated with protection in a multivariable model that included HIV-1 exposure and duration of sex work.

Human herpesvirus 8 seroconversion in Kenyan women by enzyme-linked immunosorbent assay and immunofluorescence assay

BACKGROUND

Human herpesvirus 8 (HHV-8) antibody tests vary in reported sensitivity and specificity, depending on the population tested and the assay.

OBJECTIVE

The purpose of this study was to compare the ability to detect seroconversion to HHV-8 in a cohort of HHV-8 seronegative female commercial sex workers in Kenya using three tests: HHV-8 viral lysate-based enzyme-linked immunosorbent assay (ELISA), an immunofluorescence assay for HHV-8 lytic antigens (IFA-lytic) and IFA for latent nuclear antigens (IFA-LANA).

STUDY DESIGN

By ELISA, 16 women from a prospective cohort of commercial sex workers were identified as seroconverting to HHV-8. A total of 124 post-enrollment samples from these 16 women as well as the enrollment samples were tested for HHV-8 antibodies by all three assays to monitor seroconversion.

RESULTS

Of 16 women with apparent seroconversion by ELISA, 8 had a rise in IFA-lytic titers either concomitant with or prior to the first positive ELISA sample and no initial LANA by IFA. Five of the 16 women were IFA-LANA positive at entry, indicating prior infection with HHV-8. Three women had no evidence of seroconversion by either IFA-lytic or IFA-LANA and two of these three had increased ELISA reactivity concomitant with HIV-1 infection.

CONCLUSIONS

Conversion from a negative to a positive ELISA result for HHV-8 antibody indicated seroconversion in only half of the study cohort of 16 women when IFA-lytic and IFA-LANA results were considered. The IFA-lytic assay was more sensitive than ELISA for early antibody responses. The IFA-LANA was positive in some women who had neither IFA-lytic nor ELISA antibodies suggesting it may be a marker for latent infections. Presumptive identification of incident HHV-8 infection by ELISA screening followed by IFA-lytic testing to confirm the positive test and IFA-LANA to rule out prior infection provides the most accurate documentation of HHV-8 seroconversion.

Monthly antibiotic chemoprophylaxis and incidence of sexually transmitted infections and HIV-1 infection in Kenyan sex workers: a randomized controlled trial

CONTEXT

Sexually transmitted infections (STIs) are common in female sex workers (FSWs) and may enhance susceptibility to infection with human immunodeficiency virus type 1 (HIV-1).

OBJECTIVE

To examine regular antibiotic prophylaxis in FSWs as a strategy for reducing the incidence of bacterial STIs and HIV-1.

DESIGN, SETTING, AND PARTICIPANTS

Randomized, double-blind, placebo-controlled trial conducted between 1998-2002 among FSWs in an urban slum area of Nairobi, Kenya. Of 890 FSWs screened, 466 who were seronegative for HIV-1 infection were enrolled and randomly assigned to receive azithromycin (n = 230) or placebo (n = 236). Groups were well matched at baseline for sexual risk taking and STI rates.

INTERVENTION

Monthly oral administration of 1 g of azithromycin or identical placebo, as directly observed therapy. All participants were provided with free condoms, risk-reduction counseling, and STI case management.

MAIN OUTCOME MEASURES

The primary study end point was incidence of HIV-1 infection. Secondary end points were the incidence of STIs due to Neisseria gonorrhoeae, Chlamydia trachomatis, Trichomonas vaginalis, Treponema pallidum, and Haemophilus ducreyi, as well as bacterial vaginosis. Analysis of herpes simplex virus type 2 (HSV-2) infection was performed post hoc.

RESULTS

Seventy-three percent of participants (n = 341) were followed up for 2 or more years or until they reached an administrative trial end point. Incidence of HIV-1 did not differ between treatment and placebo groups (4% [19 cases per 473 person-years of follow-up] vs 3.2% [16 cases per 495 person-years of follow-up] rate ratio [RR], 1.2; 95% CI, 0.6-2.5). Incident HIV-1 infection was associated with preceding infection with N gonorrhoeae (rate ratio [RR], 4.9; 95% CI, 1.7-14.3) or C trachomatis (RR, 3.0; 95% CI, 1.1-8.9). There was a reduced incidence in the treatment group of infection with N gonorrhoeae (RR, 0.46; 95% CI, 0.31-0.68), C trachomatis (RR, 0.38; 95% CI, 0.26-0.57), and T vaginalis (RR, 0.56; 95% CI, 0.40-0.78). The seroprevalence of HSV-2 infection at enrollment was 72.7%, and HSV-2 infection at baseline was independently associated with HIV-1 acquisition (RR, 6.3; 95% CI, 1.5-27.1).

CONCLUSIONS

Despite an association between bacterial STIs and acquisition of HIV-1 infection, the addition of monthly azithromycin prophylaxis to established HIV-1 risk reduction strategies substantially reduced the incidence of STIs but did not reduce the incidence of HIV-1. Prevalent HSV-2 infection may have been an important cofactor in acquisition of HIV-1.

A human immunodeficiency virus 1 (HIV-1) clade A vaccine in clinical trials: stimulation of HIV-specific T-cell responses by DNA and recombinant modified vaccinia virus Ankara (MVA) vaccines in humans

The immunogenicities of candidate DNA- and modified vaccinia virus Ankara (MVA)-vectored human immunodeficiency virus (HIV) vaccines were evaluated on their own and in a prime-boost regimen in phase I clinical trials in healthy uninfected individuals in the United Kingdom. Given the current lack of approaches capable of inducing broad HIV-neutralizing antibodies, the pTHr.HIVA DNA and MVA.HIVA vaccines focus solely on the induction of cell-mediated immunity. The vaccines expressed a common immunogen, HIVA, which consists of consensus HIV-1 clade A Gag p24/p17 proteins fused to a string of clade A-derived epitopes recognized by cytotoxic T lymphocytes (CTLs). Volunteers' fresh peripheral blood mononuclear cells were tested for HIV-specific responses in a validated gamma interferon enzyme-linked immunospot (ELISPOT) assay using four overlapping peptide pools across the Gag domain and three pools of known CTL epitopes present in all of the HIVA protein. Both the DNA and the MVA vaccines alone and in a DNA prime-MVA boost combination were safe and induced HIV-specific responses in 14 out of 18, seven out of eight and eight out of nine volunteers, respectively. These results are very encouraging and justify further vaccine development.

Gender Differences in Health Care-Seeking Behavior for Sexually Transmitted Diseases

BACKGROUND

Health care-seeking behavior for sexually transmitted diseases (STDs) is important in STD/HIV control.

GOAL

The goal of this study was to describe the proportion seeking care, patient delay, and choice of provider among men and women with STD-related complaints in Nairobi, Kenya.

STUDY DESIGN

A population-based questionnaire was administered in 7 randomly selected clusters (small geographic areas covering approximately 150 households each).

RESULTS

Of the 291 respondents reporting complaints, 20% of men versus 35% of women did not seek care, mainly because symptoms were not considered severe, symptoms had disappeared, or as a result of lack of money. Of those who sought care, women waited longer than men (41 vs. 16 days). Most men and women went to the private sector (72% and 57%, respectively), whereas the informal sector was rarely visited (13% and 16%, respectively). Relatively more women visited the government sector (28% vs. 15%). Because women were mostly monogamous, they did not relate their complaints to sexual intercourse, which hampered prompt care-seeking.

CONCLUSION

Women should be convinced to seek care promptly, eg, through health education in communities.

Vitamin A supplementation and genital shedding of herpes simplex virus among HIV-1-infected women: a randomized clinical trial

Cross-sectional analyses have associated vitamin A deficiency with genital shedding of herpes simplex virus (HSV) among human immunodeficiency virus type 1 (HIV-1)-infected women. A randomized clinical trial of vitamin A supplementation given daily for 6 weeks was conducted among 376 women in Mombasa, Kenya, who were coinfected with HSV-2 and HIV-1. At follow-up, there was no significant difference in the detection of genital HSV DNA between women receiving vitamin A supplementation and women receiving placebo (40% vs. 44%, respectively; P = .5) Among women shedding HSV, there was no significant difference in the mean HSV DNA quantity between the group that received vitamin A supplementation and the group that received placebo (4.51 vs. 4.67 log10 copies/swab; P = .6). HSV shedding was associated with significantly higher vaginal and cervical HIV-1 shedding, even after controlling for the plasma HIV-1 load and the CD4 count. Vitamin A supplementation is unlikely to decrease HSV shedding and infectivity.

Partner notification in the management of sexually transmitted infections in Nairobi, Kenya

OBJECTIVE

To assess utilization of partner notification as a tool in prevention and control of Sexually transmitted infections in Nairobi City Council clinics.

DESIGN

A cross-sectional study carried out between April and September 2000.

SETTING

Nairobi City Council health clinics were stratified into eight administrative divisions and a total of 16 out of 54 primary health clinics with at least four STIs patients per day were selected. A standard questionnaire was administered to every fourth patient with clinical diagnosis of STIs who gave consent on exist. Sexual partners referred by index cases during the five day period from each clinic were also enrolled into the study. An additional questionnaire was administered to HCP who were managing STIs patients and their sex partners.

RESULTS

Of 407 STIs patients recruited between April and September 2000, 20.6% were primary and 2% were secondary referrals giving an average referral rate of 23%. Respondents with multiple sex partners were less likely to refer their partners compared to those who had one partner (17.9% vs 82.1%, p < 0.005). Counseling of STI patients on the importance of partner referral was more effective than issuing referral cards alone (72.8% vs 56.8% % p = < 0.006). Barriers to partner notification included partners being out of town (44.6%) fear of quarrels and violence from partners (32.5%) and casual partners (15.1%) whose sex partners were unknown.

CONCLUSION

Counseling and understanding of STIs patients on the need to treat all sexual partners is pivotal to the success of partner referral.

Use of serum retinol-binding protein for prediction of vitamin A deficiency: effects of HIV-1 infection, protein malnutrition, and the acute phase response

BACKGROUND

Serum retinol is the most commonly used indicator of vitamin A status. Retinol is transported in a 1-to-1 complex with retinol-binding protein (RBP). RBP is easy and inexpensive to measure, and studies have shown a high correlation between concentrations of RBP and concentrations of retinol. The performance of RBP in the context of infection or protein malnutrition, however, has not been evaluated.

OBJECTIVE

Our aim was to determine whether RBP is a good surrogate measure for retinol in the context of HIV-1 infection, protein malnutrition, and the acute phase response.

DESIGN

The relation between RBP and retinol was examined in a cross-sectional study of 600 Kenyan women.

RESULTS

There was a high correlation between concentrations of RBP and those of retinol (r = 0.88). When equimolar cutoffs were used, RBP predicted marginal vitamin A status (retinol < 1.05 micro mol/L) with 93% sensitivity and 75% specificity and vitamin A deficiency (retinol < 0.70 micro mol/L) with 91% sensitivity and 94% specificity. Similarly high sensitivities and specificities were found among subgroups with HIV-1 infection, a positive acute phase response, and protein malnutrition. Protein malnutrition and a positive acute phase response were common, especially among HIV-1-infected women, and were independently and synergistically associated with lower RBP concentrations.

CONCLUSIONS

Equimolar RBP cutoffs predict vitamin A deficiency with high sensitivity and specificity, even in the context of infection and protein malnutrition. Like retinol, RBP may not accurately identify true vitamin A status under all conditions, because the acute phase response and protein malnutrition depress RBP concentrations. However, RBP may be a simple, inexpensive tool for assessment of vitamin A deficiency in population studies.

Quantitative ex vivo analysis of functional virus-specific CD8 T lymphocytes in the blood and genital tract of HIV-infected women

BACKGROUND

CD8 T lymphocytes are important in HIV-1 control and mediate virus-specific immunity in the blood and genital tract. The induction and monitoring of mucosal CD8 cell responses will be an important component of HIV-1 vaccine trials, but information regarding the frequency, phenotype and function of genital tract CD8 cell responses is lacking.

METHODS

Simultaneous blood and cervical cytobrush samples were obtained from 16 HIV-1-infected Kenyan sex workers. Epitope-specific CD8 T lymphocyte frequencies in the blood and genital tract were analysed after short-term peptide incubation and intracellular cytokine staining for interferon-gamma (IFN gamma).

RESULTS

Cervical sampling resulted in adequate cell numbers for analysis in 10/16 women. Background IFN gamma production was higher in CD3+/CD8+ lymphocytes from the genital tract than from blood (0.48% versus 0.1%; P < 0.01). Responses to staphylococcal enterotoxin B were detected in cervical CD8 lymphocytes from 10/10 women, at a similar frequency to blood (16.7% in cervix and 13.3% in blood; P = 0.4). HIV-1-specific responses were detected the cervix of 8/10 women, with a trend to higher response frequencies in the genital tract than blood (2.1% versus 0.8%; P = 0.09). Co-expression of integrin CD103 (alpha E beta 7), a mucosal marker, was used to confirm the mucosal origin of cervical responses.

CONCLUSIONS

Cytobrush sampling and intracellular cytokine staining is well suited to the analysis of cervical CD8 cell responses. The frequency of functional virus-specific CD3+/CD8+ T cells is similar in the genital tract and blood of HIV-1-infected women. The role of genital tract CD8 cell responses in HIV-1 control warrants further investigation.

Traditional healers and the management of sexually transmitted diseases in Nairobi, Kenya

To describe the role of traditional healers in STD case management, in-depth interviews were held with 16 healers (seven witchdoctors, five herbalists and four spiritual healers) in four slum areas in Nairobi, Kenya. All healers believed that STDs are sexually transmitted and recognized the main symptoms. The STD-caseload varied largely, with a median of one patient per week. Witchdoctors and herbalists dispensed herbal medication for an average of seven days, whereas spiritual healers prayed. Thirteen healers gave advice on sexual abstinence during treatment, 11 on contact treatment, four on faithfulness and three on condom use. All healers asked patients to return for review and 13 reported referring patients whose conditions persist to public or private health care facilities. Thus, traditional healers in Nairobi play a modest but significant role in STD management. Their contribution to STD health education could be strengthened, especially regarding the promotion of condoms and faithfulness.

The effect of rapid HIV-1 testing on uptake of perinatal HIV-1 interventions: a randomized clinical trial

OBJECTIVE

We examined whether HIV-1 testing using a rapid assay increases the proportion of pregnant women obtaining HIV-1 results and the uptake of perinatal HIV-1 interventions.

METHODS

Pregnant women attending public health clinics in Nairobi were offered voluntary counselling and testing for HIV-1. Consenting women were randomly assigned to receive either rapid or conventional HIV-1 testing. Women randomly assigned to rapid testing were allowed to receive same-day results or to return later. The results for women randomly assigned to conventional enzyme-linked immunosorbent assay (ELISA) testing were available after 7 days. HIV-1-infected women were referred for antiretroviral prophylaxis to prevent mother-to-child transmission of HIV-1.

RESULTS

Among 1282 women offered voluntary HIV-1 testing and counselling, 1249 accepted testing, of whom 627 were randomly assigned to rapid testing and 622 to conventional testing. The median duration between testing and obtaining results was 0 days for women who received rapid testing compared with 11 days for women who received conventional testing. The percentage receiving HIV-1 results was significantly higher among women who received rapid testing compared with conventional testing. Of 161 HIV-1-seropositive women, only 24 received antiretroviral prophylaxis. The uptake of perinatal HIV-1 interventions did not differ between HIV-1-seropositive women randomly assigned to rapid testing or conventional ELISA testing.

CONCLUSION

Rapid HIV-1 testing significantly increased the proportion of women receiving HIV-1 results, which is important for sexual and perinatal HIV-1 prevention. The challenge remains to improve the uptake of perinatal HIV-1 interventions among HIV-1-seropositive women.

Association between cervical shedding of herpes simplex virus and HIV-1

OBJECTIVE

To investigate the association between the cervical shedding of herpes simplex virus (HSV) and HIV-1.

DESIGN

A cross-sectional study on 200 women seropositive for both HSV-2 and HIV-1 was conducted in a family planning clinic at the Coast Provincial General Hospital, Mombasa, Kenya.

MAIN OUTCOME MEASURES

Quantities of HSV DNA (types 1 and 2) and HIV-1 RNA as well as the presence or absence of HIV-1 proviral DNA in cervical secretions were determined and compared.

RESULTS

There was a significant correlation between the quantities of HSV DNA and HIV-1 RNA in the cervical secretions of HSV-shedding women (Pearson's r = 0.24, P = 0.05). A 10-fold increase in the quantity of cervical HSV DNA was associated with 1.35-fold higher cervical HIV-1-RNA levels (95% CI 1.00-1.81; P = 0.05), and with 1.36-fold greater odds of detection of HIV-1 proviral DNA (95% CI 1.05-1.75; P = 0.02).

CONCLUSION

Higher levels of cervical HSV were associated with higher levels of expressed HIV-1 and with the more frequent detection of HIV-1-infected cells in cervical secretions. Prospective studies are needed to explore further the association between non-ulcerative cervical HSV reactivation and HIV-1 shedding. Such a relationship may have important implications for interventions designed to slow the spread of HIV-1.

Correlates of human herpesvirus 8 seropositivity among heterosexual men in Kenya

BACKGROUND

Several studies have suggested that sexual transmission of human herpesvirus 8 (HHV-8) occurs among homosexual men in developed countries. However, few studies have examined heterosexual HHV-8 transmission, especially among African populations in which HHV-8 is endemic.

OBJECTIVES

To determine the seroprevalence and correlates of HHV-8 infection among heterosexual African men.

DESIGN

Cross-sectional study.

METHODS

Participants were 1061 men enrolled in a prospective cohort study of risk factors for HIV-1 acquisition among trucking company employees in Mombasa, Kenya. Stored frozen sera from the study baseline visit were tested for antibodies to HHV-8 by whole-virus lysate ELISA.

RESULTS

HHV-8 seroprevalence was 43%. In multivariate logistic regression analysis, HHV-8 infection was independently associated with older age [for men aged 30-39 years: odds ratio (OR), 1.5; 95% confidence interval (CI), 1.1-2.0; for men aged > or = 40 years: OR, 1.7; 95% CI, 1.1-2.7, compared with men aged < 30 years], Christian religion (OR, 1.6; 95% CI, 1.2-2.1), being uncircumcised (OR, 1.5; 95% CI, 1.0-2.2), and ever having syphilis (OR, 2.2; 95% CI, 1.4-3.5). Ever having used condoms was associated with decreased likelihood of infection (OR, 0.7; 95% CI, 0.6-1.0). Seropositivity was not significantly related to other sexual behaviors characterized or to HIV-1 status.

CONCLUSIONS

HHV-8 seropositivity is common in this population and increases with age, suggesting on-going transmission during adulthood. Infection was more common among men who were uncircumcised or who had ever had syphilis and was less common among those who had ever used condoms, suggesting that sexual factors may play a role in HHV-8 transmission. Prospective studies of HHV-8 acquisition in heterosexual African populations are needed to demonstrate whether safer sexual practices can reduce transmission.

Vitamin A deficiency and the acute phase response among HIV-1-infected and -uninfected women in Kenya

Among HIV-1-infected individuals, vitamin A deficiency has been associated with faster disease progression and greater infectivity in observational studies, but randomized clinical trials have shown no effect of vitamin A supplementation. We conducted a cross-sectional study of 400 HIV-1-infected and 200 HIV-1-uninfected women in Mombasa, Kenya to examine the relations between vitamin A deficiency (serum retinol <30 microg/dL) and HIV-1 status, HIV-1 disease stage, and the acute phase response (serum C-reactive protein >or=10 mg/L and/or alpha1-acid glycoprotein >or=1.2 g/L). Among the HIV-1-infected women, the effect of vitamin A supplementation was examined in a randomized trial. Vitamin A deficiency was independently associated with HIV-1 infection (OR = 2.7, 95% CI: 1.9-4.0) and the acute phase response (OR = 2.8, 95% CI: 1.9-4.1). Among HIV-1-infected women, vitamin A deficiency and the acute phase response were associated with each other and were both independently associated with higher HIV-1 plasma viral load and lower CD4 count. HIV-1-infected women having an acute phase response had no increase in serum vitamin A levels after supplementation. Serum levels increased significantly among women without an acute phase response, although not to normal levels among women who were deficient at baseline. Among HIV-1-infected individuals, it is likely that low serum vitamin A concentrations reflect more active infection and the acute phase response. These results provide possible explanations for the disparity between observational studies and randomized trials of vitamin A for HIV-1 infection.

HLA typing in a Kenyan cohort identifies novel class I alleles that restrict cytotoxic T-cell responses to local HIV-1 clades

OBJECTIVES

To investigate HLA class I allele frequencies in a Kenyan commercial sex worker (CSW) cohort, and to examine HIV-1 specific cytotoxic T lymphocyte (CTL) responses directed against epitopes derived from locally prevalent clade A virus.

METHODS

PCR-single strand polymorphism HLA class I typing. Sequencing of novel alleles and examination of their distribution in the CSW cohort, and a low risk HIV uninfected cohort. The peptide-binding motif of a novel class I allele was predicted, and a panel of candidate CTL epitopes was synthesized whose functional significance was examined using ELISpot and Cr release assays.

RESULTS

Class I HLA-A and B frequencies within the cohort are presented. Two novel class I alleles were found, HLA-B*4415 and HLA-Cw*0407. These two class I alleles were relatively common, both in the CSW cohort (2.1% and 3.3% respectively) and in a cohort of lower risk women (1.9% and 3.8% respectively). Allele HLA-B*4415 restricted CTL responses against a novel epitope (EEKAFSPEV) derived from p24 of clade A HIV-1, and HLA-Cw0407 restricted CTL against a predefined HLA-Cw*0401 gp120 epitope.

CONCLUSIONS

Multi-epitope vaccine design requires knowledge of HLA class I distribution and HIV CTL epitope characterization in potential target populations. The description of two novel HLA class I alleles at high frequency in this high risk Kenyan CSW cohort suggests that HLA mapping of vaccine cohorts and subsequent characterization of local CTL epitopes will be warranted prior to vaccine trials.

Cross-clade HIV-1-specific neutralizing IgA in mucosal and systemic compartments of HIV-1-exposed, persistently seronegative subjects

There is an urgent need for a universally effective HIV-1 vaccine, but whether a vaccine will be able to protect against HIV-1 of different clades is a significant concern. IgA from HIV-1-exposed, persistently seronegative (HEPS) subjects has been shown to neutralize HIV-1 and to block epithelial HIV-1 transcytosis, and it may target novel HIV-1 epitopes. We have tested the ability of plasma and mucosal IgA purified from HEPS subjects to neutralize HIV-1 primary isolates of different viral clades and phenotypes. IgA from two groups of HEPS subjects was tested: sex workers from Nairobi, Kenya, where clades A and D predominate, and the heterosexual partners of individuals infected by clade B virus. HIV-1-infected and low-risk uninfected individuals were included as controls. IgA purified from the blood, genital tract, and saliva of most HEPS sex workers demonstrated significant cross-clade HIV-1 neutralization, whereas a more clade-restricted pattern of neutralization was found in partners of clade B-infected individuals. IgA purified from HIV-1-infected individuals also mediated cross-clade neutralization, whereas IgA from uninfected controls lacked neutralizing activity. In conclusion, mucosal and plasma IgA from HEPS subjects neutralizes HIV-1 of different clades. This ability to induce HIV-1-specific systemic and mucosal IgA may be an important feature of an effective prophylactic HIV-1 vaccine.

Childcare practices of commercial sex workers

OBJECTIVE

To determine the childcare practices of commercial sex workers (CSWs).

DESIGN

A descriptive cross-sectional survey was conducted between July and December 2000 during which a structured questionnaire was administered.

SETTING

Kibera slum, Nairobi, Kenya.

SUBJECTS

Three hundred eighty five CSWs and four focus group discussions (FGDs) held. Health cards from 126 under five years old children belonging to the respondents were reviewed for immunization status and regularity of growth monitoring.

RESULTS

The mean age of the 385 CSWs surveyed was 32 +/- 7 years and mean duration of sex work was 6 +/- 4 years. The mean number of living children was 3.4 +/- 2 and 81.2% of the mothers lived with their children. Three quarters of the CSWs practised prostitution at home. The most common daily childcare activities by the mothers were food preparation (96.2%) and washing children's clothes (91.3%). Overall 96.8% of their under-five years old children were fully immunized and 80% of their under one year old children had their growth monitored monthly. About three quarters of the mothers with adolescent children educated them on HIV/STDs. Health seeking behaviour for the children was hampered by health care cost (71.4%) and consumption of alcohol by the mothers. Like other mothers, the CSWs encouraged their adolescent children to take up some adult roles such as maintaining a clean house (93.3%). However only 2.0% took time to converse or counsel the children. Focus group discussions (FGDs) with the CSWs showed that children were left unattended at night while the mothers went out in search of clients. Efforts to provide better education for the children were undermined by lack of funds (52.2%) and truancy (46.6%). One third of the study population had invested for the future maintenance of their children.

CONCLUSION

There was more emphasis on physical, rather than psychological aspect of childcare. The practice of living with the children ensured that earnings from the sex trade were used for the immediate needs of the children such as food. However this practice had a negative influence on the children as the majority of the respondents conducted their sexual business at home with little or no privacy. Health seeking behaviour for the children was hampered by lack of funds and to some extent alcohol consumption by the mothers. Efforts to invest in the education of their children were undermined by lack of funds and truancy.

A prospective study of hormonal contraceptive use and cervical shedding of herpes simplex virus in human immunodeficiency virus type 1-seropositive women

Cross-sectional analyses have demonstrated an association between use of hormonal contraceptives and shedding of herpes simplex virus (HSV). This prospective study evaluated the effect of initiating use of hormonal contraception on cervical HSV detection. Two hundred women who were seropositive for HSV-2 and human immunodeficiency virus (HIV) type 1 were examined for cervical mucosal HSV by use of quantitative DNA polymerase chain reaction before and after beginning the use of hormonal contraceptives. Cervical HSV was detected in 32 women (16.0%) before initiating and in 25 women (12.5%) after initiating use of hormonal contraception (P=.4). There were no significant differences in HSV shedding among the subgroups of women starting combination oral contraceptives containing both estrogen and progesterone or progesterone-only contraceptives. Among the 54 women who shed HSV at least once, the median change in cervical HSV after initiation of hormonal contraception was -313 copies/swab. In this prospective study, use of hormonal contraceptives did not increase detection of cervical HSV.

Gonococcal cervicitis is associated with reduced systemic CD8+ T cell responses in human immunodeficiency virus type 1-infected and exposed, uninfected sex workers

Neisseria gonorrhoeae cervicitis and human immunodeficiency virus (HIV) type 1 frequently coinfect core transmitter populations, such as female sex workers. Gonococcal cervicitis is associated with increased viral shedding and plasma viremia in HIV-1-infected women and increased HIV-1 susceptibility in uninfected women. We studied the influence of gonococcal cervicitis on CD8(+) interferon (IFN)-gamma responses to HIV-1 and cytomegalovirus (CMV) epitopes in HIV-1-infected and in highly-exposed, persistently seronegative (HEPS) female sex workers. In HIV-1-infected women, gonococcal cervicitis was associated with reduced IFN-gamma responses in bulk CD8(+) lymphocyte populations, and intracellular cytokine staining, combined with class I major histocompatibility complex (MHC)-peptide tetramer studies, demonstrated reduced IFN-gamma production by HIV-1 epitope-specific CD8(+) lymphocytes. In HEPS sex workers, cervicitis was associated with the transient loss of systemic HIV-1-specific CD8(+) responses and with reduced function of CMV-specific CD8(+) lymphocytes. Impaired function of virus-specific CD8(+) lymphocytes may partly explain the deleterious effects of gonococcal cervicitis on HIV-1 immune control and susceptibility.

Cross-reactive cytotoxic T lymphocytes against a HIV-1 p24 epitope in slow progressors with B*57

OBJECTIVES

To determine whether CD8 T lymphocytes from HIV-1-infected patients expressing B*5701 and B*5703 show broad cross-reactivity against different variants of a conserved p24 epitope, which might account for the good prognosis of HIV-1-infected individuals with HLA-B*57.

DESIGN

B*5701+ and B*5703+ were recruited from Nairobi, Kenya and from Oxford, UK. All patients had been HIV positive for at least 8 years and could be categorized as slow progressors.

METHODS

CD8 cytotoxic T cell clones were generated from B*5701+ and B*5703+ donors and tested for their ability to recognize clade variants of an index p24 epitope in standard cytolytic assays. Cross-reactive responses in freshly isolated peripheral blood mononuclear cells (PBMC) were assessed by interferon-gamma (IFNgamma) production and tetramer binding.

RESULTS

Broad cross-clade reactivity for both cytolysis and tetramer binding was observed in CD8 T cell clones from patients harbouring the index epitope sequence. Patterns of cross-reactivity were similar in freshly isolated PBMC but varied between individuals in terms of strength and breath of responses generated. One common variant induced an unusual response with tetramer binding but often failed to induce IFNgamma production, and another was a weak stimulator of both IFNgamma and cytolytic activity.

CONCLUSION

B*5701+ and B5703+ donors demonstrate broad functional cross-reactivity to both common and rare variants of a dominant p24 epitope, which could be relevant to the association of B*57 alleles with slow progression to AIDS.

Reduced HIV risk-taking and low HIV incidence after enrollment and risk-reduction counseling in a sexually transmitted disease prevention trial in Nairobi, Kenya

There is an urgent need in sub-Saharan Africa to develop more effective methods of HIV prevention, including improved strategies of sexually transmitted infection (STI) prevention or an HIV vaccine. The efficacy of these strategies may be tested through clinical trials within cohorts at high risk for STI and HIV, such as female commercial sex workers. For ethical reasons, standard HIV prevention services, including access to free condoms, risk-reduction counseling, and STI therapy, will generally be offered to all study subjects. Because study subjects would often not otherwise have access to these prevention services, it is possible that enrollment in such clinical trials will itself reduce incidence rates of STI and HIV below expected levels, reducing the power to test the efficacy of the randomized intervention. We show that the provision of standard HIV prevention services as part of a randomized STI/HIV prevention trial is temporally associated with a dramatic reduction in sexual risk-taking, and that this reduction is directly associated with reduced STI incidence. This finding should be considered in the design of clinical trials with an endpoint of HIV incidence, in particular HIV preventive vaccine trials.

Vitamin A supplementation and human immunodeficiency virus type 1 shedding in women: results of a randomized clinical trial

Observational studies have associated vitamin A deficiency with vaginal shedding of human immunodeficiency virus (HIV) type 1-infected cells and mother-to-child HIV-1 transmission. To assess the effect of vitamin A supplementation on vaginal shedding of HIV-1, a randomized, double-blind, placebo-controlled trial of 6 weeks of daily oral vitamin A (10,000 IU of retinyl palmitate) was conducted among 400 HIV-1-infected women in Mombasa, Kenya. At follow-up, there was no statistically significant difference in the prevalence of HIV-1 DNA (18% vs. 21%, P=.4) or the quantity of HIV-1 RNA (3.12 vs. 3.00 log(10) copies/swab, P=1.0) in vaginal secretions of women receiving vitamin A, compared with women receiving placebo. No significant effect of supplementation on plasma HIV-1 load or CD4 or CD8 cell counts was observed, and no effect was seen among women who were vitamin A deficient at baseline. Vitamin A supplementation is unlikely to decrease the infectivity of women infected with HIV-1.

Association between Mycoplasma genitalium and acute endometritis

Up to 70% of cases of pelvic inflammatory disease do not have a known cause. We recruited 115 women who had presented to a clinic for sexually transmitted diseases in Nairobi, Kenya with pelvic pain that had persisted for 14 days or less, to look for an association between Mycoplasma genitalium and endometritis. With PCR, we detected M genitalium in the cervix, endometrium, or both in nine (16%) of 58 women with histologically confirmed endometritis and in one (2%) of 57 women without endometritis (p=0.02). Our results suggest that infection with M genitalium is strongly associated with acute endometritis in this population.

Human leucocyte antigen supertypes and immune susceptibility to HIV-1, implications for vaccine design

T cell responses against HIV-1 have been identified in a number of exposed uninfected populations. We hypothesized that the ability to mount an effective T cell response is partly determined by the human leucocyte antigens (HLA) phenotype of the individual. We examined whether certain HLA supertypes were associated with differential HIV-1 susceptibility in sexually exposed adults and in the setting of mother to child HIV-1 transmission. By multivariate analysis, decreased HIV-1 infection risk was strongly associated with possession of a cluster of closely related class I HLA alleles (A2/6802 supertype) in sexually exposed adults (Hazard ratio=0.42, 95% confidence intervals (CI): 0.22-0.81, P=0.009) and perinatally exposed infants (Odds ratio=0.12, 95% CI: 0.03-0.54, P=0.006). The alleles in this HLA supertype are known in some cases, to present the same peptide epitopes (termed 'supertopes'), for T cell recognition. The identification of HIV-1 supertopes, which are associated with protection from HIV-1 infection, has important implications for the application of epitope-based HIV-l vaccines in a variety of racial groups.

Quality of sexually transmitted disease case management in Nairobi, Kenya: a comparison among different types of healthcare facilities

BACKGROUND

In Nairobi, the prevalence for sexually transmitted diseases (STDs) among attenders at antenatal and family planning clinics is substantial, but knowledge about the quality of STD case management is scarce.

GOAL

To assess quality of STD case management in Nairobi healthcare facilities.

STUDY DESIGN

All the facilities in five sublocations were enumerated. In 142 facilities, 165 providers were interviewed, observed during 441 interactions with patients who had STDs, and visited by a simulated patient.

RESULTS

For observations of patients with STDs, correct history-taking ranged from 60% to 92% among the various types of facilities, correct examination from 31% to 66%, and correct treatment from 30% to 75%. The percentage of correctness for all three aspects (World Health Organization prevention indicator 6) varied between 14% and 48%. Public clinics equipped for STD care performed best in all aspects, whereas treatment was poorest in pharmacies and private clinics. The providers trained in STD management performed better than those without training.

CONCLUSIONS

Quality of STD case management was unsatisfactory except in public STD-equipped clinics. This indicates the need for improvement by interventions such as further training in syndromic management, improved supervision, and the introduction of prepackaged syndromic management kits.

New insights into HIV-1 specific cytotoxic T-lymphocyte responses in exposed, persistently seronegative Kenyan sex workers

A clearer understanding of HIV-1 specific immune responses in highly-exposed, persistently seronegative (HEPS) subjects is important in developing models of HIV-1 protective immunity. HIV-1 specific cytotoxic T-lymphocytes (CTL) have been described in a cohort of HEPS Kenyan sex workers, and recent work has further elucidated these responses. CTL specific for HIV-1 Env were found in the blood of over half the sex workers meeting criteria for HIV resistance, and in some women recognized unmapped epitopes. The proportion of women with Env-specific CTL increased with the duration of uninfected HIV exposure, suggesting that these responses were acquired over time. CD8+ lymphocyte responses directed against predefined HIV-1 CTL epitopes from various HIV-1 genes were found in the blood and genital tract of >50% resistant sex workers, at a ten-fold lower frequency than in infected subjects. The epitope specificity of CD8+ responses differs between HEPS and HIV infected women, and in HEPS the maintenance of responses appears to be dependent on persistent HIV exposure. Several HIV-1 'resistant' sex workers have become HIV infected over the past 6 years, possibly related to waning of pre-existing HIV-specific CTL, and infection has often been associated with a switch in the epitope specificity of CD8+ responses. These findings suggest that vaccine-induced protective HIV immunity is a realistic goal, but that vaccine strategies of boosting or persistent antigen may be necessary for long-lived protection.

Functional HIV-1 specific IgA antibodies in HIV-1 exposed, persistently IgG seronegative female sex workers

Although HIV-specific cellular immune responses are found in a number of HIV highly-exposed, persistently seronegative (HEPS) cohorts, late seroconversion can occur despite pre-existing cytotoxic T lymphocytes (CTL), suggesting that a protective HIV vaccine may need to induce a broader range of HIV-specific immune responses. Low levels of HIV-specific IgA have been found in the genital tract and plasma of the majority of Nairobi HEPS sex workers and appeared to be independent of HIV-specific cellular responses. IgA purified from genital tract, saliva and plasma of most HEPS sex workers were able to neutralize infection of PBMC by a primary (NSI) clade B HIV isolate, as well as viral isolates from clades A and D, which predominate in Kenya. In addition, these IgA were able to inhibit transcytosis of infective HIV virions across a transwell model of the human mucosal epithelium in an HIV-specific manner. Preliminary work in other HEPS cohorts has suggested the recognition of different gp41 epitopes in HEPS and HIV-infected subjects. Although present at low levels, these IgA demonstrated cross-clade neutralizing activity and were able to inhibit HIV mucosal transcytosis, suggesting an important functional role in protection against HIV infection.

Quality of health education during STD case management in Nairobi, Kenya

Quality of health education during STD case management in Nairobi was assessed in 142 healthcare facilities, through interviews of 165 providers, observation of 441 STD patients managed by these providers, and 165 visits of simulated patients. For observations, scores were high for education on contact treatment (74-80%) and compliance (83%), but unsatisfactory for counselling (52%) and condom promotion (20-41%). The World Health Organization (WHO) indicator for STD case management Prevention Indicator 7 (PI7) (condom promotion plus contact treatment) was poor (38%). Public clinics strengthened for STD care generally performed best, whereas pharmacies and mission clinics performed worst. Compared with observations, scores were higher during interviews and lower during simulated patient visits, indicating that knowledge was not fully translated into practice. Interventions to improve the presently unsatisfactory service quality would be wide distribution of health education materials, ongoing training and supervision of providers, implementation of STD management checklists, and the introduction of pre-packaged kits for STD management.

Hormonal contraception and risk of sexually transmitted disease acquisition: results from a prospective study

OBJECTIVES

To examine the relationship between use of oral contraceptive pills or depot medroxyprogesterone acetate and sexually transmitted disease acquisition.

STUDY DESIGN

Prospective cohort included 948 Kenyan prostitutes. Multivariate Andersen-Gill proportional hazards models were constructed, adjusting for sexual behavioral and demographic variables.

RESULTS

When compared with women who were using no contraception, users of oral contraceptive pills were at increased risk for acquisition of chlamydia (hazard ratio, 1.8; 95% confidence interval, 1.1-2.9) and vaginal candidiasis (hazard ratio, 1.5; 95% confidence interval, 1.2-1.9) and at decreased risk for bacterial vaginosis (hazard ratio, 0.8; 95% confidence interval, 0.7-1.0). Women using depot medroxyprogesterone acetate had significantly increased risk of chlamydia infection (hazard ratio, 1.6; 95% confidence interval, 1.1-2.4) and significantly decreased risk of bacterial vaginosis (hazard ratio, 0.7; 95% confidence interval, 0.5-0.8), trichomoniasis (hazard ratio, 0.6; 95% confidence interval, 0.4-1.0), and pelvic inflammatory disease (hazard ratio, 0.4; 95% confidence interval, 0.2-0.7). Consistent condom use was associated with significantly decreased risk of gonorrhea, chlamydia, genital ulcer disease, bacterial vaginosis, and pelvic inflammatory disease.

CONCLUSIONS

The use of oral or injectable hormonal contraception altered susceptibility to sexually transmitted diseases, which may in turn influence transmission of human immunodeficiency virus type 1. Consistent condom use was protective with regards to sexually transmitted disease and should be encouraged for the prevention of sexually transmitted disease and human immunodeficiency virus type 1 among women who use hormonal contraception.

Sexually transmitted infections and vaginal douching in a population of female sex workers in Nairobi, Kenya

OBJECTIVE

To assess the association between vaginal douching and sexually transmitted infections (STI) among a group of female sex workers (FSWs) in Nairobi, Kenya.

METHODS

This study was part of a randomised, placebo controlled trial of monthly prophylaxis with 1 g of azithromycin to prevent STIs and HIV infection in a cohort of Nairobi FSWs. Consenting women were administered a questionnaire and screened for STIs.

RESULTS

The seroprevalence of HIV-1 among 543 FSWs screened was 30%. HIV infection was significantly associated with bacterial vaginosis (BV), trichomoniasis, gonorrhoea, and the presence of a genital ulcer. Regular douching was reported by 72% of the women, of whom the majority inserted fluids in the vagina, generally after each sexual intercourse. Water with soap was the fluid most often used (81%), followed by salty water (18%), water alone (9%), and a commercial antiseptic (5%). Douching in general and douching with soap and water were significantly associated with bacterial vaginosis (p = 0.05 and p = 0.04 respectively). There was a significant trend for increased frequency of douching and higher prevalence of BV. There was no direct relation observed between douching and risk for HIV infection or other STIs.

CONCLUSION

The widespread habit of douching among African female sex workers was confirmed. The association between vaginal douching and BV is of concern, given the increased risk of HIV infection with BV, which has now been shown in several studies. It is unclear why we could not demonstrate a direct association between douching and HIV infection. Further research is required to better understand the complex relation between douching, risk for bacterial vaginosis, and risk for HIV and other STIs.

CD8(+) lymphocytes respond to different HIV epitopes in seronegative and infected subjects

HIV-1-specific cytotoxic T-lymphocyte (CTL) responses have been detected at a low frequency in many HIV-1-exposed, persistently seronegative (HEPS) subjects. However, it is unclear how CTLs could protect against HIV acquisition in HEPS subjects, when high levels of circulating CTL fail to prevent disease progression in most seropositive subjects. To address this issue we studied CD8(+) lymphocyte responses to a panel of HIV-1 CTL epitopes in 91 HEPS and 87 HIV-1-infected Nairobi sex workers. HIV-specific responses in seropositive women focused strongly on epitopes rarely or never recognized in HEPS subjects, who targeted epitopes that were subdominant or unrecognized in infected women. These differences in epitope specificity were restricted by only those HLA class I alleles that are associated with a reduced risk of HIV-1 infection in this cohort. Late seroconversion in HEPS donors was associated with a switch in epitope specificity and/or immunodominance to those epitopes preferentially recognized by HIV-1-infected women. The likelihood of detecting HIV-1-specific responses in HEPS women increased with the duration of viral exposure, suggesting that HIV-1-specific CD8(+) responses are acquired over time. The association between differential recognition of distinct CTL epitopes and protection from HIV-1 infection may have significant implications for vaccine design.

Female condom introduction and sexually transmitted infection prevalence: results of a community intervention trial in Kenya

OBJECTIVE

To measure the impact on sexually transmitted infection (STI) prevalence of a female condom introduction and risk-reduction program at Kenyan agricultural sites.

DESIGN

We conducted a cluster-randomized trial to determine whether a replicable, community-level intervention would reduce STI prevalence.

METHODS

Six matched pairs of tea, coffee and flower plantations were identified. The six intervention sites received an information/motivation program with free distribution of female and male condoms, and six control sites received only male condoms and related information. Participants were tested for cervical gonorrhea and chlamydia by ligase chain reaction on urine specimens, and vaginal trichomoniasis by culture, at baseline, 6 and 12 months.

RESULTS

Participants at intervention (n = 969) and control sites (n = 960) were similar; baseline STI prevalence was 23.9%. Consistent male condom use was more than 20% at 12 months. Consistent female condom use was reported by 11 and 7% of intervention site women at 6 and 12 months. Unadjusted STI prevalence was 16.5 and 17.4% at 6 months, and 18.3 and 18.5% at 12 months, at the intervention and control sites, respectively. Logistic regression models confirmed the null effect of the female condom intervention.

CONCLUSIONS

Female condom introduction did not enhance STI prevention at these sites. It is unclear which aspects of the intervention -- STI education, condom promotion, case management -- were associated with decreased STI prevalence from baseline to follow-up.

Selenium deficiency is associated with shedding of HIV-1--infected cells in the female genital tract

OBJECTIVE

To assess the relation between selenium deficiency and vaginal or cervical shedding of HIV-1-infected cells.

DESIGN

Cross-sectional study of 318 HIV-1 seropositive women in Mombasa, Kenya.

METHODS

Vaginal and cervical swab specimens were tested for the presence of HIV-1 DNA by polymerase chain reaction. Multivariate logistic regression models, adjusting for CD4 count and vitamin A deficiency, were used.

RESULTS

Selenium deficiency (defined as levels <85 microg/L) was observed in 11% of the study population. In unstratified multivariate analyses, there was no significant association between selenium deficiency and vaginal or cervical shedding. In stratified analyses, however, significant associations became apparent after excluding women with predictors of shedding with strong local effects on the genital tract mucosa. Among women who did not use oral contraceptives and who did not have vaginal candidiasis, selenium deficiency was significantly associated with vaginal shedding (adjusted odds ratio [AOR] 2.9, 95% confidence interval [CI] 1.0--8.8, p =.05). Effect modification was also observed in the relation between selenium deficiency and cervical shedding, with a significant association seen among those women who were not using oral contraceptive pills or depot medroxyprogesterone acetate and who did not have Neisseria gonorrhoeae infection (AOR 2.8, 95% CI 1.1--7.0, p =.02).

CONCLUSIONS

We found selenium deficiency to be associated with a nearly threefold higher likelihood of genital mucosal shedding of HIV-1--infected cells, suggesting that deficiency may increase the infectiousness of women with HIV-1. Nutritional interventions to prevent HIV-1 transmission warrant investigation.

Vitamin A and risk of HIV-1 seroconversion among Kenyan men with genital ulcers

BACKGROUND

Vitamin A is involved in normal immune function and the maintenance of mucosal integrity through complex effects on cellular differentiation.

OBJECTIVE

We sought to determine whether serum vitamin A levels were associated with altered susceptibility to primary infection with HIV-1 in men with high-risk sexual behaviour and genital ulcers who presented for treatment at an STD clinic in Nairobi, Kenya.

METHODS

HIV-1 seronegative men were prospectively followed. Vitamin A levels at study entry were compared among 38 men who HIV-1 seroconverted versus 94 controls who remained HIV seronegative.

RESULTS

Vitamin A deficiency (retinol less than 20 microg/dl) was very common and was present in 50% of HIV-1 seroconverters versus 76% of persistent seronegatives. Seroconversion was independently associated with a retinol level greater than 20 microg/dl (HR 2.43, 95% CI 1.25-4.70, P = 0.009), and a genital ulcer aetiology caused by Haemophilus ducreyi (HR 3.49, 95% CI 1.03-11.67, P = 0.04). Circumcision was independently associated with protection (HR 0.46, 95% CI 0.23-0.93, P = 0.03).

CONCLUSION

Vitamin A deficiency was not associated with an increased risk of HIV-1 infection among men with concurrent STD. A decreased risk of HIV-1 seroconversion was independently associated with lower retinol levels. The effects of vitamin A on macrophage and lymphoid cell differentiation may paradoxically increase mucosal susceptibility to HIV-1 in some vulnerable individuals, such as men with genital ulcers. Lack of circumcision and chancroid are confirmed as important co-factors for heterosexual HIV-1 transmission. The role of vitamin A in heterosexual HIV-1 transmission requires further study.

Validation of a modified commercial enzyme-linked immunoassay for detection of human immunodeficiency virus type 1 immunoglobulin G antibodies in saliva

This study was performed to evaluate the performance of a saliva collection device (OmniSal) and an enzyme-linked immunoassay (EIA) designed for use on serum samples (Detect HIV1/2) to detect human immunodeficiency virus type 1 (HIV-1) antibodies in the saliva of high-risk women in Mombasa, Kenya. The results of the saliva assay were compared to a "gold standard" of a double-EIA testing algorithm performed on serum. Individuals were considered HIV-1 seropositive if their serum tested positive for antibodies to HIV-1 by two different EIAs. The commercial serum-based EIA was modified to test the saliva samples by altering the dilution and lowering the cutoff point of the assay. Using the saliva sample, the EIA correctly identified 102 of the 103 seropositive individuals, yielding a sensitivity of 99% (95% confidence interval [CI], 94 to 100%), and 96 of the 96 seronegative individuals, yielding a specificity of 100% (95% CI, 95 to 100%). In this high-risk population, the positive predictive value of the assay was 100% and the negative predictive value was 99%. We conclude that HIV-1 antibody testing of saliva samples collected with this device and tested by this EIA is of sufficient sensitivity and specificity to make this protocol useful in epidemiological studies.

The HLA A2/6802 supertype is associated with reduced risk of perinatal human immunodeficiency virus type 1 transmission

Certain HLAs may, in part, account for differences in human immunodeficiency virus type 1 (HIV-1) susceptibility by presenting conserved immunogenic epitopes for T cell recognition. The HLA supertype A2/6802 is associated with decreased susceptibility to HIV-1 among sex workers. The alleles in this supertype present the same HIV-1 peptide epitopes for T cell recognition in some cases. This study sought to determine whether the HLA A2/6802 supertype influenced HIV-1 transmission in a prospective cohort of HIV-1-infected mothers and children in Kenya. Decreased perinatal HIV-1 infection risk was strongly associated with possession of a functional cluster of related HLA alleles, called the A2/6802 supertype (odds ratio, 0.12; 95% confidence interval, 0.03-0.54; P=.006). This effect was independent of the protective effect of maternal-child HLA discordance. These data provide further evidence that HLA supertypes are associated with differential susceptibility to HIV-1 transmission.

Late seroconversion in HIV-resistant Nairobi prostitutes despite pre-existing HIV-specific CD8+ responses

Resistance to HIV infection in a small group of Kenyan sex workers is associated with CD8+-lymphocyte responses to HIV cytotoxic T-lymphocyte (CTL) epitopes. Eleven prostitutes meeting criteria for HIV resistance seroconverted between 1996 and 1999. The occurrence and specificity of preexisting HIV-1 epitope-specific responses were examined using the IFN-gamma enzyme-linked immunospot assay, and any epitopes recognized were cloned and sequenced from the infecting viral isolate. Immunologic and behavioral variables were compared between late seroconverters and persistently uninfected sex worker controls. HIV-1 CTL epitope responses were present in four of six cases, 5-18 months before seroconversion, and their presence was confirmed by bulk CTL culture. A possible viral escape mutation was found in one of six epitopes. The key epidemiologic correlate of late seroconversion was a reduction in sex work over the preceding year. In persistently uninfected controls, a break from sex work was associated with a loss of HIV-specific CD8+ responses. Late seroconversion may occur in HIV-1-resistant sex workers despite preceding HIV-specific CD8+ responses. Seroconversion generally occurs in the absence of detectable CTL escape mutations and may relate to the waning of HIV-specific CD8+ responses due to reduced antigenic exposure.