HIV-1 infection in HIV-1 enzyme-linked immunoassay seronegative patients in Kinshasa, Zaire

Serum samples of 62 African patients who had clinical manifestations of HIV-1 infection but were seronegative for HIV-1 by ELISA (Organon) were subsequently further tested by another HIV-1 ELISA test (Wellcozyme), HIV-1 IgG Western blot, HIV-1 antigen detection and HIV-2 ELISA. Patients' lymphocytes were cultured for HIV-1 and 2. Because of limited quantities of serum available all tests were not performed on all samples. Seven (26%) of 27 sera of patients meeting the WHO clinical case definition of AIDS were Western-blot-positive. In contrast, of 35 patients' sera with possible HIV related disease, only one (3%) was Western blot positive (P = 0.02) and none of 75 sera from HIV-1 ELISA (Organon) seronegative blood donors (P less than 0.01) were Western blot positive. Of 30 HIV-1 ELISA (Organon) seronegative patients tested with the HIV-1 ELISA Wellcozyme assay only one was seropositive (this patient's serum was also Western blot positive). Of 17 HIV-1 ELISA (Organon) seronegative patients tested, HIV-1 antigen was found in 1 case (6%) (this patient's serum was Western blot negative). None of the 34 patients tested by HIV-2 serology was HIV-2 seropositive. HIV-1 was isolated by culture in 3 (21%) of 14 HIV-1 ELISA seronegative patients (sera of the 3 patients were Western blot negative). In total, 12 (19%) of 62 HIV-1 ELISA (Organon) seronegative patients were found to be positive for HIV, either by Western blot HIV antigen testing or viral culture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Factors associated with HIV-1 infection among sex workers of Addis Ababa, Ethiopia

OBJECTIVE: To study the prevalence and risk factors for HIV infection among sex workers of Addis Ababa, Ethiopia. Design and methods: Cross-sectional survey on socio-demographic characteristics, behaviours, and HIV serological status of sex workers attending two health centres of Addis Ababa. RESULTS: HIV prevalence among sex workers was 274 of 372 (73.7%). Several factors were significantly associated with an increased risk of being HIV-infected [among others, working in 'shared rooms', high number of clients, use of injectable hormones, and positive Treponema pallidum particle agglutination (TPPA) serology], and others with a decreased risk (being born in Addis Ababa, high level of education, peer education on sex work, condom use, use of oral pill, and use of condoms for contraception). Of interest, sex workers who were using condoms for contraception were, compared with others, more likely to use condoms consistently (65 versus 24%, respectively; P < 0.001), and less likely to be HIV-infected (55 versus 86%, respectively; P < 0.001). In multivariate analysis [log-binomial model, giving estimates of the prevalence ratio (PR)], being born in Addis Ababa (PR = 0.74; 95% confidence interval (CI), 0.61-0.91), using condoms for contraception (PR = 0.73; 95% CI, 0.64-0.85), and a positive TPPA serology (PR = 1.21; 95% CI, 1.09-1.36), remained significantly associated with HIV infection. CONCLUSIONS: HIV prevalence was remarkably high among sex workers of Addis Ababa. Condom use was higher, and HIV prevalence lower, in sex workers using condoms not only for prevention of HIV and sexually transmitted diseases, but also for contraceptive purpose. This finding is of particular interest for its implications for prevention strategies among sex workers in the developing world.     

A common human leucocyte antigen-DP genotype is associated with resistance to HIV-1 infection in Kenyan sex workers

Human leucocyte antigen-DP presents peptides to CD4 T cells and plays an important role in parasitic infections and autoimmune diseases, yet its influence on HIV-1 susceptibility has not been well studied. Here, we report several human leucocyte antigen-DP genotypes associated with HIV-1 susceptibility in Kenyan sex workers. Among these, one common genotype stands out. DPA1*010301 (frequency = 60.4%) was associated with HIV-1 resistance (P = 0.033, odds ratio = 1.585, 95% confidence interval = 1.036-2.425) and slower seroconversion (P = 0.001, log rank = 0.595, 95% confidence interval = 0.433-0.817). The discovery of common human leucocyte antigen-DP genotypes contributing to HIV-1 immunity may help overcome difficulties encountered with highly polymorphic human leucocyte antigens.     

Plasma viraemia in seronegative HIV-1-infected individuals.

It has been reported that the period of latency between HIV-1 infection and the production of antibodies against the virus is sometimes prolonged for greater than 6 months. However, the data supporting this are still controversial and it is not known whether these individuals are actually infectious, especially through body fluids. We have performed a prospective study of 65 high-risk HIV-1-antibody-negative individuals who were followed-up for a period of at least 1 year. Twelve of these individuals were shown by polymerase chain reaction (PCR) to be carriers of HIV-1 proviral sequences. The virus was isolated from lymphocytes in five out of 10 PCR-positive subjects and from cell-free plasma in two. Our data indicate that in some cases delayed seroconversions may be associated with productive infection, suggesting that mechanism(s) other than viral latency may be responsible for the absence of antibody responses to HIV-1 proteins.     

HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan sex workers

OBJECTIVES: Most HIV-1 transmission is sexual; therefore, immune responses in the genital mucosa may be important in mediating protection against HIV infection. This study examined HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan female sex workers. METHODS: HIV-1-specific immune responses were compared in HIV-1-resistant and HIV-1-infected sex workers, and in lower risk uninfected women. Cervical and vaginal samples from each group were tested for HIV-1-specific IgA and IgG by enzyme immunoassay. Systemic T-helper lymphocyte cell responses to HIV-1 envelope peptide epitopes were assayed using an interleukin 2 bioassay. HIV-1 risk-taking behaviours were assessed using standardized questionnaires. RESULTS: HIV-1-specific IgA was present in the genital tract of 16 out of 21 (76%) HIV-1-resistant sex workers, five out of 19 (26%) infected women, and three out of 28 (11%) lower risk women (P < 0.0001). Among lower risk women, the presence of HIV-1-specific IgA was associated with HIV-1 risk-taking behaviour. Systemic T-helper lymphocyte responses to HIV-1 envelope peptides were present in 11 out of 20 (55%) HIV-1-resistant women, four out of 18 (22%) infected women, and one out of 25 (4%) lower risk women (P < 0.001). T-helper lymphocyte responses did not correlate with the presence or titre of virus-specific mucosal IgA in any study group. CONCLUSIONS: HIV-1-specific IgA is present in the genital tract of most HIV-1-resistant Kenyan sex workers, and of a minority of lower risk uninfected women, where it is associated with risk-taking behaviour. These data suggest a role for mucosal HIV-1-specific IgA responses in HIV-1 resistance, independent of host cellular responses.     

Rapid increase of both HIV-1 infection and syphilis among pregnant women in Nairobi, Kenya.

OBJECTIVE: To determine the prevalence of HIV-1 and syphilis antibodies in a population of pregnant women in Nairobi, Kenya, between 1989 and 1991. METHODS: As part of an ongoing prospective study on the effect of HIV-1 infection and sexually transmitted diseases, 4883 pregnant women were screened for HIV-1 and syphilis antibodies in one health-centre in Nairobi. RESULTS: HIV-1 seroprevalence increased from 6.5 to 13.0% (P < 0.001) and syphilis seroreactivity from 2.9 to 5.3% (P = 0.002), while there was no change in gonococcal infection rates. The most rapid increase in HIV-1 prevalence was observed in women aged less than 25 years. There was no evidence of demographic fluctuations in the population during this time, or of changes in sexual behaviour, except that fewer women enrolled in 1991 reported having more than one sex partner, compared with women enrolled in 1989 (39.1 versus 20.0%; P = 0.0001). HIV-1-seropositive women were more likely to be seroreactive for syphilis than HIV-1-seronegative mothers (7.7 versus 3.2%; odds ratio = 2.5; 95% confidence interval, 1.7-3.8; P < 0.001), but there was no difference between the two groups in terms of gonorrhoea prevalence. CONCLUSION: These data confirm an association between HIV-1 and syphilis infection, and indicate that both are spreading rapidly among women in Nairobi outside high-risk groups. Increased efforts to control both infections are urgently required.     

HIV-1 acquisition and disease progression are associated with decreased high-risk sexual behaviour among Kenyan female sex workers

BACKGROUND: Changes in sexual risk behaviour may occur following HIV-1 infection. OBJECTIVE: To test the hypothesis that HIV-1 seroconversion and disease progression are associated with changes in risk behaviours, using data from a cohort of Kenyan female sex workers (FSWs). METHODS: HIV-1-seronegative FSWs were enrolled in a prospective cohort study of risk factors for HIV-1 acquisition. At monthly visits, standardized interviews were conducted to assess sexual risk behaviour and HIV-1 serologic testing was performed. Seroconverters were invited to continue with follow-up. Between 1993 and 2004 (when antiretroviral therapy was introduced in the cohort), 265 women seroconverted for HIV-1 (incidence 7.7/100 person-years) and were included in this analysis. RESULTS: Unprotected intercourse was reported at 546/2037 (27%) pre-seroconversion visits versus 557/3732 (15%) post-seroconversion visits (P < 0.001). These findings remained significant after adjustment for potential confounding factors [adjusted odds ratio (AOR) 0.69; 95% confidence interval (CI), 0.55-0.86]. Compared with HIV-1-seronegative women, there was a progressive stepwise decrease in unprotected intercourse among HIV-1-seropositive women with CD4 cell counts > or = 500 (AOR, 0.93; 95% CI, 0.62-1.39), 200-499 (AOR, 0.58; 95% CI, 0.41-0.82) and < 200 cells/microl (AOR, 0.45; 95% CI, 0.25-0.82). Decreases in unprotected intercourse reflected increases in both abstinence and 100% condom use. Women also reported fewer partners and fewer episodes of intercourse after HIV-1 seroconversion. CONCLUSIONS: HIV-1 seroconversion and disease progression were associated with decreases in sexual risk behaviour among Kenyan FSWs.     

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.     

Sinusitis in HIV-1 infection.

PURPOSE: To determine the clinical and radiographic characteristics of sinusitis in patients with human immunodeficiency virus type 1 (HIV-1) infection. PATIENTS AND METHODS: A retrospective study was performed that identified all HIV-1-infected patients with sinus radiographs, sinus computed tomograms, or magnetic resonance imaging of the head between 1982 and 1989 (n = 145). Medical record review detailed the clinical course and laboratory parameters in all patients. RESULTS: Eighty-nine patients had radiographic evidence of sinusitis; 75 patients had adequate clinical data and comprise the study group. Acute sinusitis was seen in 10 patients (13%), while all 75 patients had mucosal thickening indicative of chronic sinusitis. Fifty patients (67%) were symptomatic with fever, nasal congestion or discharge, and headache being the most common symptoms; nineteen patients (25%) were asymptomatic when their radiographs showed active disease. The mean CD4 count for the group was 276 cells/mm3; 32 (43%) had CD4 counts less than or equal to 100 cells/mm3. Twenty-three patients (31%) received antibiotics orally, parenterally, or both. CONCLUSIONS: Sinusitis appears to occur frequently in HIV-infected patients, is often asymptomatic, may be recurrent or refractory, and may be associated with declining immunocompetence in HIV-infected patients.     

Curdlan sulfate and HIV-1. I. In vitro inhibitory effects of curdlan sulfate on HIV-1 infection.

Action mechanisms of a newly synthesized polysaccharide, curdlan sulfate (CRDS), on human immunodeficiency virus type 1 (HIV-1) infection were investigated in vitro using syncytium formation microassay and p24 antigen capture enzyme-linked immunosorbent assay. These assays measured the titer of infectious virions and the amounts of HIV-1 core antigen p24 in soluble, intraviral, and intracellular forms. CRDS treatments were performed for 1 h at 37 degrees C. H9 cells pretreated with 0.1 to 100.0 micrograms/ml of CRDS appreciably inhibited HIV-1 infection. CRDS-treated HIV-1 virions were less able to infect H9 cells than untreated virions. The simultaneous treatment of H9 cells and HIV-1 virions with CRDS induced a significant inhibition of HIV-1 infection, resulting in the temporary disappearance of virions at the highest dose of CRDS. In contrast, CRDS treatment of newly HIV-1-infected H9 cells caused a significant decrease in the titer of infectious HIV-1 and the p24 amounts of all three forms, but no absolute elimination. Taken together, these results indicate that CRDS may block the binding of the HIV-1 envelope to the H9 cell surface, with emphasis on the high affinity of CRDS to the HIV-1 envelope.     

Sociodemographic characteristics, care, feeding practices, and growth of cohorts of children born to HIV-1 seropositive and seronegative mothers in Nairobi, Kenya

OBJECTIVES To compare sociodemographic profiles, child care, child feeding practices and growth indices of children born to HIV-1 seropositive and seronegative mothers. METHODS: A cohort study of 234 children (seropositive and seronegative) born to HIV-1 seropositive mothers and 139 children born to seronegative mothers in Pumwani Maternity Hospital which serves a low-income population in Nairobi, Kenya from December 1991 and January 1994. RESULTS: With few exceptions, at the time of their birth children in all three cohorts had parents with similar characteristics, lived in similar housing in similar geographical areas, had their mothers as their primary care givers, had similar feeding practices and similar growth status and patterns. However, the HIV-1 seropositive mothers were slightly younger (23.8 years vs. 25.0 years, P < 0.01), if married they were less likely to be their husband's first wife (79% vs. 91%, P = 0.02) and more likely to have a one-room house (75% vs. 63%, P = 0.04). All three cohorts had mean Z-scores in length-for-age and in weight-for-height within the normal range (>/= 2.0 Z-scores) from birth to 21 months with the exception of the length-for-age of the seropositive children at the 18-month visit. In all cohorts length-for-age became more compromised than weight-for-length, dropping to about -1.45 Z-score by 21 months; in contrast, weight-for-length dropped to about -0.5 Z-score by this age. The only statistically significant differences in growth indices among the three cohorts were between the two cohorts of seronegative children: those with seronegative mothers were less compromised in length-for-age at 1.5 months (mean Z-score = -0.19 vs. -0.48, P < 0.05) and more compromised in weight-for-length at 6 months (mean Z-score = 0.10 vs. 0.45, P < 0.05) and at 18 months (mean Z-score = -0.73 vs. -0.16, P < 0.05). 27-34% were exclusively breastfed at 1.5 months; 52-61% consumed solid foods in addition to breast milk by 2.5 months. CONCLUSIONS: Low-income HIV-1 seropositive- and seronegative-born children were from families with similar characteristics and similar housing environments. Similar growth patterns in the cohorts suggest that the challenging environment and the choice of weaning foods had an impact on all three cohorts. The aggressive care given the children with HIV-1 seropositive mothers and their children may have reduced the progression and impact of HIV-1 disease on the growth of the seropositive children. Further research is needed to corroborate our findings to be certain that our results are not affected by loss to follow-up bias: we lost the same proportion in all three cohorts but cannot verify that the children we lost had the same growth patterns as those who remained in the study.