Child survival in children born to HIV-2 infected women in Guinea-Bissau, West Africa

We have retrospectively studied the effect of maternal HIV-2 infection and other risk factors on child survival at a family planning centre in Bissau, Guinea-Bissau. A total of 2109 women were included, and the seroprevalence of HIV-2 was 5.7%. Overall child mortality of all live births (n=5912) reported by the women (standardized for age of the mother) was slightly higher among children of HIV-2 seropositive mothers (16.3%) compared with children of HIV seronegative women (14.6%) (not significant). There was a significant association between low level of maternal education and increased child mortality, but no difference in the level of education was found between HIV-2 seropositive and seronegative women.     

Longstanding presence of HIV-2 infection in Guinea-Bissau (West Africa)

We have retrospectively studied the seroprevalence of the human immunodeficiency virus (HIV) in Guinea-Bissau in a sample of sera collected from the whole country in 1980. We tested a total of 1248 individuals and found 11 individuals who were seropositive for HIV-2 but there were no HIV-1 seropositive samples. The mean age of the HIV-2 seropositive people was significantly higher than the age of the seronegative individuals. In the different areas surveyed, the HIV-2 seroprevalence ranged from 0 to 2.5%. A central region of the country, grossly centred in the capital city of Bissau, presented the highest prevalence of HIV-2 seropositivity (>2%), which contrasts with its virtual absence from the more remote rural areas located near the borders with the neighbouring countries. The overall seroprevalence found for HIV-2 in this study is 0.9% (1.8%, when considering the adult seroprevalence only), which proves that the virus was definitely circulating in Guinea-Bissau at the beginning of the 1980s.     

High concordance between polymerase chain reaction and antibody testing of specimens from individuals dually infected with HIV types 1 and 2 in Guinea-Bissau, West Africa.

In this study we have evaluated the concordance between serology, using five commercially available antibody assays designed to discriminate between HIV-1 and HIV-2, and the polymerase chain reaction (PCR) for the detection of HIV-1 and HIV-2 dual infection. Thirty-seven HIV-1 and HIV-2 dually reactive serum samples from individuals in Guinea-Bissau with total CD4+ T lymphocyte counts ranging from 9 to 948 x 10(6)/liter were included in the study. All samples were tested by Multispot, Pepti-LAV, and Immunocomb HIV-1 and HIV-2 discriminatory antibody assays. Thirty-two of the 37 samples were also tested by a combination of two HIV type-specific antibody enzyme-linked immunosorbent assays (ELISA; Wellcozyme HIV-1 and Murex HIV-2). Each sample showed dual reactivity in all or any of these assays. A nested PCR based on primer systems in the vif and pol regions of HIV-1 and in the gag and LTR regions of HIV-2 was used to evaluate the serological results. Thirty samples from HIV-1 antibody-positive individuals and 30 samples from HIV-2 antibody-positive individuals were all PCR positive with their corresponding primer systems. The type specificity was 100% for all of the primer systems. The concordance between dual HIV-1 and HIV-2 reactivity on the serological assays and PCR was 77.7% for Multispot, 80% for Pepti-LAV, 81.8% for Immunocomb, and 85.7% for the two ELISAs used in combination. Thus the majority of individuals included in this study appeared to be truly dually infected. The study shows that it is possible, through a careful selection of assays, to reach a high concordance between serological assays and PCR in studying HIV-1 and HIV-2 dual infections.     

Trends and interaction of HIV-1 and HIV-2 in Guinea-Bissau, west Africa: no protection of HIV-2 against HIV-1 infection.

OBJECTIVES: To study trends in the prevalence and incidence of HIV-1 and HIV-2 infections in Guinea-Bissau over the last 7 years, and to evaluate the protective effect of HIV-2 against HIV-1 infection. DESIGN: Prospective follow-up of a cohort of police officers in Guinea-Bissau, and sentinel surveillance of pregnant women in Bissau. METHODS: Participants in the police cohort were tested regularly for antibodies to HIV and Treponema pallidum, and information about sexual risk behaviour and a history of sexually transmitted diseases was obtained. Simultaneously, pregnant women at the maternity wards at the National Hospital in Bissau were screened annually for HIV antibodies. To evaluate changes in prevalence and incidence of HIV in the police cohort, the study period was divided into three time strata with 2-3 years in each stratum. For the evaluation of a protective effect of HIV-2 on subsequent HIV-1 infection, two multivariate Poisson regression models were constructed, adjusting for different selected confounding variables. RESULTS: Between 1990 and 1997, 2637 police officers were included in the cohort study, 90.7% of whom were male. The overall prevalence of HIV-1 was 0.9%, of HIV-2 it was 9.7% and of HIV-1 and HIV-2 dual reactivity it was 0.5%. For pregnant women the prevalence rates were 0.9, 5.5 and 0.2% for HIV-1, HIV-2 and dual reactivity respectively. The prevalence of HIV-1 increased significantly whereas the prevalence of HIV-2 declined significantly during the study period, among both police officers and pregnant women. The total incidence of HIV-1 and HIV-2 was 0.74 and 0.83 per 100 person-years respectively in the police cohort. The incidence of HIV-1 increased slightly from 0.62 to 0.78 per 100 person-years (not significant), whereas the incidence of HIV-2 declined significantly from 0.90 to 0.35 per 100 person-years over the study period. Seven police officers seroconverted from HIV-2 to dual reactivity (1.22 per 100 person-years). The adjusted incidence ratio of acquiring HIV-1 infection among HIV-2-positive subjects compared with HIV-negative subjects was 1.65 [95% confidence interval (CI), 0.73-3.74] and 1.98 (95% CI, 0.80-4.87), depending on the confounding variables included. CONCLUSIONS: Our study shows an increasing prevalence of HIV-1 and a decreasing prevalence of HIV-2 in Guinea-Bissau. The incidence of HIV-2 declined significantly whereas the incidence of HIV-1 was relatively stable over the study period. No protective effect of HIV-2 against subsequent HIV-1 infection was observed, instead HIV-2-positive subjects had a tendency towards higher risk of acquiring HIV-1 infection compared with seronegative subjects.     

Low levels of HIV-1 plasma viral load in patients infected with HIV-1 subtype b and advanced immunosuppression

OBJECTIVES: Some HIV-1 infected patients show low levels of viraemia despite having advanced immunosuppression. Cases with falsely undetectable viraemia by conventional PCR have been reported when patients were infected with non-B subtypes. The aim of this study was to investigate whether this immunovirological discordance can be due to the presence of HIV-1 non-B subtypes, and whether a modified PCR procedure can yield different HIV viraemia values in these cases. METHODS: Fifteen HIV-infected patients either naive for antiretroviral drugs or under treatment, with HIV plasma viraemia below 1000 copies/mm(3)and CD4+ cell counts lesser than 500 or 300 cells/mm(3), respectively, were included. Serotyping, genotyping and HIV plasmatic viraemia determinations were performed in all individuals. RESULTS: In five out of six treatment-naive patients the virus was categorized as non-B subtype by serotyping, although only one case was confirmed by genotyping as HIV-2. Eight out of nine patients under antiretroviral therapy were subtype B carriers by serotyping and confirmed by genotyping. The remaining patient was determined as a subtype A carrier by both procedures. A modified PCR procedure (Amplicor HIV Monitor Test version 1.5) did not yield higher viral load levels than the former version. CONCLUSIONS: The presence of HIV-1 subtypes non-B can explain a minority of cases of this immunovirological discordance, but in most of them the reason is still unknown. Likewise, a PCR procedure adapted for detecting HIV-1 non-B subtypes fails to find higher plasma viraemia in patients with such a discordance.     

Incidence of HIV-1 dual infection and its association with increased viral load set point in a cohort of HIV-1 subtype C-infected female sex workers

This longitudinal study aimed to determine the incidence and pathogenic implications of dual human immunodeficiency virus type 1 (HIV-1) infection in a cohort of female sex workers. Blood samples from 31 recently infected women were screened by use of a heteroduplex mobility assay and sequencing. The median viral load set point was 5404 copies/mL (n=22), which was measured by use of the bDNA assay. Within 3 months of infection, 19% (6/31) of the women were dually infected with 2 distinct HIV-1 subtype C viruses. No evidence of superinfection was detected over the course of 24 months of follow-up, indicating that the risk of dual infection is highest around the time of the initial infection. There was a significant association between dual infection and elevated viral load set point.     

Mortality of HIV-1, HIV-2 and HIV-1/HIV-2 dually infected patients in a clinic-based cohort in The Gambia

OBJECTIVE: To assess and compare the mortality rates of patients with HIV-1, HIV-2 or both infections (HIV-D) in the same population. DESIGN: Clinic-based cohort study. METHODS: HIV-seropositive patients aged 15 years and older who attended the Medical Research Council clinics in Fajara between May 1986 and September 1997 were recruited. Clinical assessment using the Karnofsky score, CDC cell staging, WHO staging, and CD4 cell counts was performed at baseline. Patients attended clinic every 3 months; if they did not attend, they were visited at home by field workers to ascertain survival status. No patient was on antiretroviral therapy during the study period. RESULTS: Data from 1519 HIV-positive adult patients were analysed. A total of 746 patients had HIV-1, 666 HIV-2, and 107 patients had HIV-D. A total of 828 patients (55%) died, and 161 (11%) were lost to follow-up. The median follow-up was 12 months (range 0-128). CD4 cell counts were available for 894 patients. Compared with HIV-1, the adjusted hazards ratio for mortality in the CD4 cell count category 500 cells/microl or greater was 0.50 for HIV-2 (95% CI 0.28-0.88) and 1.27 (95% CI 0.51-3.7) for HIV-D. Among those with CD4 cell counts less than 500 cells/microl the mortality rates in HIV-2 and HIV-D were similar to those in HIV-1. DISCUSSION: HIV-2-infected patients with CD4 cell counts of 500 cells/microl and greater had a significantly lower mortality rate than HIV-1-infected patients. HIV-2-infected patients with advanced disease had the same poor prognosis as patients with HIV-1. Dually infected patients had mortality rates similar to HIV-1.     

HIV-1 viral DNA load in peripheral blood mononuclear cells from seroconverters and long-term infected individuals.

OBJECTIVE: To determine viral DNA load in peripheral blood mononuclear cells (PBMC) from HIV-1-infected individuals. DESIGN: HIV-1 copy numbers were determined using a quantitative polymerase chain reaction (PCR), the PCR-aided template titration assay (PATTY). PATTY utilizes an internal plasmid control DNA, which is amplified within the same tube and using the same primers as the PBMC target DNA. HIV-1 copy numbers were confirmed by limiting-dilution PCR analysis. RESULTS: PBMC viral load of 19 long-term (greater than 4 years) HIV-1-infected individuals ranged from 0.8 to 100 copies per 10(3) PBMC. Significantly higher copy numbers were found among p24-antigen-positive than among p24-antigen-negative individuals. In addition, the PBMC viral load of two HIV-1-infected individuals was monitored during the first 3 months after acute infection. For both patients, the HIV-1 copy numbers were shown to peak at the time of HIV-1-antibody seroconversion and decline subsequently (range, 0.6-10 copies per 10(3) PBMC). CONCLUSIONS: PATTY is a useful method for assessing the HIV-1 copy numbers in PBMC DNA. Viral DNA load peaks shortly after infection and reaches an individual specific level that is probably stable within a few months of infection. Viral DNA load in PBMC varies widely among long-term HIV-1-infected individuals.     

Plasma RNA viral load predicts the rate of CD4 T cell decline and death in HIV-2-infected patients in West Africa

OBJECTIVE: To examine whether the levels of plasma RNA and DNA provirus predict the rate of CD4 cell decline and patient death. DESIGN: Retrospective analysis of HIV-2 cohort subjects. METHODS: Fifty-two subjects were recruited between January 1991 and December 1992. HIV-2 RNA levels in plasma and DNA levels in peripheral blood mononuclear cells (PBMC) were measured using in-house quantitative PCR assays. The annual rate of CD4 cell decline was calculated using the least-squares method. The survival data on 31 December 1997 were used. RESULTS: The mean percentage of CD4 cells at baseline was 30.7 (SD, 9.5). In a linear regression model, the annual rate of CD4 cell decline was 1.76 CD4% faster for every increase in one log10 RNA copies/ml [95% confidence interval (CI), 0.81-2.7; P = 0.0006; r = 0.46; n = 52] and 1.76 CD4% faster for every increase in log10 DNA copies/10(5) PBMC (95% CI 0.46-3.1; P = 0.01; r = 0.33; n = 42). In a multiple linear regression model, RNA load was related to CD4 decline independently of DNA load (P = 0.02). The overall mortality rate was 7.29/100 person-years. In a Cox regression model, the hazard rate increased by 2.12 for each log10 increase in RNA load (95% CI, 1.3-3.5; P = 0.0023) but only by 1.09 for each log10 increase in DNA load (95% CI, 0.64-1.87; P = 0.8). CONCLUSION: This longitudinal study shows for the first time that a baseline HIV-2 RNA load predicts the rate of disease progression. HIV-2-infected patients with a high viral load may need to be treated as vigorously as HIV-1 patients.     

Maternal plasma viral load, zidovudine and mother-to-child transmission of HIV-1 in Africa: DITRAME ANRS 049a trial

OBJECTIVE: To study the relationship between maternal plasma RNA levels and mother-to-child transmission (MTCT) of HIV-1 in African breastfed children. DESIGN: Nested case-control study within a randomized trial assessing the efficacy of a short maternal zidovudine (ZDV) regimen to reduce MTCT. METHODS: Eligible women received either 300 mg of ZDV twice a day until labour, 600 mg at the beginning of labour and 300 mg twice a day for 7 days post-partum or a placebo. The diagnosis of paediatric HIV-1 infection was based on PCR tests at days 1--8, 45, 90 and 180 then on serology performed at 3 monthl intervals. Plasma HIV-1 RNA was measured at inclusion and on day 8 after delivery for all women who did transmit HIV to their children (cases) using a Chiron branched DNA assay (sensitivity 50 copies/ml) and compared with women who did not transmit (two per case) matched for phase trial, treatment allocation and site. RESULTS: At inclusion, mean log10 viral load was 4.6 among 55 transmitting mothers and 3.7 among 117 non transmitters (P = 0.0001). Among transmitters, the mean difference in log10 viral load between day 8 post-partum and inclusion was -0.13 in the ZDV group (n = 23) versus 0.27 in the placebo group (n = 32; P = 0.01); among non transmitters it was -0.35 for the ZDV group (n = 47) versus 0.27 in the placebo group (n = 70; P < 10(-4)). In multivariate logistic regression analysis, odds ratios for MTCT were 8.7 (95% confidence interval, 3.7-20.6) for 1 log(10) increase of maternal RNA at inclusion and 4.2 (95% confidence interval, 1.7--10.3) for 1 log(10) increase difference from inclusion to day 8 post-partum. CONCLUSION: High maternal viral load at inclusion strongly predicts MTCT of HIV in Africa. A short ZDV treatment regimen decreases significantly maternal viral load from its pretreatment level.     

Genetic variability of human immunodeficiency virus type 2 C2V3 region within and between individuals from Bissau, Guinea-Bissau, West Africa

The V3 loop of both HIV-1 and HIV-2 is characterized by a high degree of genetic variation. To investigate the spectrum of HIV-2 variability in nature we have focused on the C2V3 region of Env and analyzed 108 viral sequences obtained from uncultured peripheral blood mononuclear cells obtained from 16 HIV-2-seropositive individuals from Bissau (Guinea-Bissau). The estimated values of genetic divergence between individuals were higher than those calculated from sequence information collected in a single individual. We have also found that the sequences surrounding the V3 loop contribute significantly to the overall genetic diversity of the C2V3 region of HIV-2 gp105, while the V3 loop itself seems to be rather conserved. Phylogenetic analysis demonstrated that all the individuals enrolled in this study were infected with HIV-2 subtype A viruses.     

Change in plasma viral load, and viral DNA and mRNA burdens, in peripheral blood mononuclear cells from patients infected with HIV-1

OBJECTIVES: To clarify the virological state of human immunodeficiency virus (HIV)-1-infected patients, we compared the plasma HIV-1 RNA copy number (plasma viral load (VL)), viral DNA and mRNA burdens in peripheral blood mononuclear cells (PBMCs), and the other clinical predictors. METHODS: One hundred and thirty-one samples of PBMCs and plasma from 26 patients infected with HIV-1 were obtained during 20 consecutive months for the measurement of VL, viral DNA and mRNA burdens, and CD4 positive (CD4+) cells count. The quantitative polymerase chain reaction (PCR) method with detection by solid phase DNA was utilized for the assay of VL, viral DNA and mRNA burdens. RESULTS: Eighty-six VL, 101 viral mRNA and 129 viral DNA out of 131 samples were detected. There was a significant positive correlation between VL and the viral mRNA burden (r = 0.600, P < or = 0.001), and between VL and the viral DNA burden (r = 0.368, P < or = 0.001). Focused on individuals, the viral mRNA burdens varied in a manner relatively dependent on VL when both values were detectable. However, viral DNA burdens varied relatively independently of VL and the viral mRNA burdens. In six patients the viral mRNA burden was detectable and changed even if the VL was undetectable throughout the observation period. CONCLUSIONS: Both viral DNA and viral mRNA burdens still showed detectable changes even when the VLs became undetectable in most patients. The measurement of viral mRNA or DNA burdens may be clinically available to identify viral replication when VL is undetectable.     

HLA-Bw4-B*57 and Cw*18 alleles are associated with plasma viral load modulation in HIV-1 infected individuals in Salvador,Brazil

Host genetic factors play an important role in mediating resistance to HIV-1 infection and may modify the course of infection. HLA-B alleles (Bw4 epitope; B*27 and B*57) as well as killer cell immunoglobulin-like receptors have been associated with slow progression of HIV-1 infection. Objective: To evaluate the association between serological epitopes HLA-Bw4 and HLA-Bw6 and prognostic markers in AIDS. Methods: 147 HIV-infected individuals in Bahia, Northeast Brazil, were genotyped for HLA class I locus. HLA class I genotyping was performed by hybridization with sequence-specific oligonucleotide probes following amplification of the corresponding HLA-A, HLA-B and HLA-C genes. Statistical analysis was performed using Fishe?s exact and ANOVA tests for categorical and continuous variables, respectively. Results: We detected a significant association (χ² = 4.856; p = 0.018) between the presence of HLA-Bw4 and low levels of viremia. Eighteen out of the 147 HIV-infected individuals presented viremia ≤ 1,800 copies/mL and 129 presented viremia > 2,000 copies/mL. Ninety and four percent (17/18) of all individuals with viremia ≤ 1,800 copies/ mL carried HLA-Bw4, compared to 67.4% (87/129) of individuals with viremia > 2,000 copies/mL. Additionally, we found a significantly higher frequency of B*57 (OR = 13.94; 95% CI = 4.19-46.38; p < 0.0001) and Cw*18 (OR = 16.15; 95% CI = 3.46-75.43; p ≤ 0.0001) alleles, favoring the group with lower viremia levels, in comparison with those with higher viral load. Conclusion: HLA-Bw4-B*57 and Cw*18 alleles are associated with lower level of viral load in HIV-infected Brazilian patients. These findings may help us in understanding the determinants of HIV evolution in Brazilian patients, as well as in providing important information on immune response correlates of protection for such population.     

Suppression of HIV-1 plasma viral load below detection preserves IL-17 producing T cells in HIV-1 infection

IL-17 is proinflammatory cytokine secreted by a unique CD4+ T (Th17) cell subset and proposed to play a role in host defense. We hypothesized that Th17 cells are lost in HIV-1 infection. HIV-1-infected children with plasma viremia below 50 copies/ml had IL-17 production, whereas those with detectable viremia had minimal secretion. These results imply viral-mediated destruction or impairment of Th17 cells and argue for complete suppression of viremia for reconstitution of Th17 cells.