Mother to child transmission of HIV-1 in a Thai population: role of virus characteristics and maternal humoral immune response.

The objective of this study was to investigate factors influencing mother to child transmission of HIV-1 in Thailand, where HIV-1 CRF01_AE, the major subtype in Southeast Asia, predominates. Samples from 84 HIV-1 infected, anti-retroviral treatment-naïve, non-breast feeding mothers, 28 who transmitted HIV-1 to their babies (transmitters) and 56 who did not (non-transmitters), were studied for maternal humoral immune response and virus characteristics. Maternal humoral immune response was measured by lymphocyte phenotyping; neutralizing antibodies to laboratory HIV-1 MN strain and two clinical isolates; peptide binding antibody to gp41 and V3 from strains CRF01_AE, B, and MN; autologous antibodies; and quasispecies diversity. Virus characteristics studied were viral load, co-receptor usage, and viral replication capacity. No significant difference between transmitters and non-transmitters was found for any parameter of maternal humoral immune response. However, viral load and viral replication capacity were significantly higher in transmitters versus non-transmitters and were not correlated with each other. This suggests that viral replication capacity may be a transmission factor independent of viral load, which is already well established as a risk factor for transmission of HIV-1. All except four viral isolates used the CCR5 co-receptor. This is one of few studies of vertical transmission in a population where HIV-1 CRF01_AE predominates. The data suggest that in this population the maternal humoral immune response was not important in preventing transmission at parturition, but that virus characteristics were key factors, and that viral replication capacity may contribute to birth-associated mother to child transmission of HIV-1.

Assessment of bacille Calmette-Guérin vaccine reaction in HIV-exposed Thai infants.

We evaluated local reactions at 1, 2, and 4 months of age to bacille Calmette-Guérin vaccine given at birth to 1058 infants who were exposed to human immunodeficiency virus (HIV). No scar was discernible in 12 (12.4%) of 97 HIV-infected infants and 20 (2.1%) of 961 uninfected infants (relative risk, 5.9; 95% confidence interval, 3.0-11.8). This difference may reflect poorer immunogenicity in HIV-infected infants.

Human papillomavirus (HPV) detection among human immunodeficiency virus-infected pregnant Thai women: implications for future HPV immunization.

BACKGROUND: Human immunodeficiency virus (HIV)-infected women are at increased risk for developing cervical cancer and for infection with human papillomavirus (HPV). Prophylactic vaccines targeting HPV types 16 and 18 are being evaluated for efficacy among young women. GOAL: The goal was to assess the prevalence of HPV among HIV-infected pregnant women in Bangkok and to evaluate the need for prophylactic HPV vaccines studies in this population. STUDY DESIGN: The study population consisted of 256 HIV-infected pregnant women who participated in a mother-to-child HIV transmission trial. Stored cervicovaginal lavage samples were tested for the presence of HPV DNA by polymerase chain reaction with PGMY09/11 primers and reverse line-blot hybridization for determination of anogenital HPV types. RESULTS: HPV prevalence was 35.5% (91/256); high-risk HPV prevalence was 23.4% (60/256). HPV type 16 or 18 was present in 8.2% (21/256). Almost half of all infections were multiple. Furthermore, overall HPV detection was associated with abnormal cervical cytology (P<0.001) and higher HIV-plasma viral load (P=0.007). CONCLUSIONS: Only one-quarter of HIV-infected pregnant women in Bangkok had high-risk HPV types; less than 10% had HPV types 16 or 18. As the HPV prevalence is expected to increase during HIV disease, prophylactic vaccines targeting HPV types 16 and 18 should be studied among HIV-infected women not yet infected with these HPV types and not previously exposed.

Evaluating programs to prevent mother-to-child HIV transmission in two large Bangkok hospitals, 1999-2001.

The 2 largest maternity hospitals in Bangkok implemented comprehensive programs to prevent mother-to-child HIV transmission in 1998. We conducted a cross-sectional survey of post-partum HIV-infected women in 1999 through 2001 to evaluate these programs. Women were given structured interviews at 0 to 3 days, 1 month, and 2 months postpartum. Medical records of women and their newborns were reviewed. Of 488 enrolled women, 443 (91%) had antenatal care: 391 (88%) at study hospitals and 52 (12%) elsewhere. The HIV diagnosis was first known before pregnancy for 61 (13%) women, during pregnancy for 357 (73%) women, during labor for 22 (5%) women, and shortly after delivery for 48 (10%) women. Antenatal zidovudine (ZDV) was used by 347 (71%) women, and intrapartum ZDV was used by 372 (76%) women. Twelve (55%) of the 22 women who first learned of their HIV infection during labor took intrapartum ZDV. All 495 newborn infants started prophylactic ZDV; the first dose was given within 12 hours for 491 (99%) children. Ten (2%) children were breast-fed at least once by their mother, and 10 (2%) were breast-fed at least once by someone else. Although uptake of services was high, inconsistent antenatal care, fear of stigmatization, and difficulty in disclosing HIV status prevented some women from using services.

Survival, disease manifestations, and early predictors of disease progression among children with perinatal human immunodeficiency virus infection in Thailand.

OBJECTIVE: To describe survival and signs of human immunodeficiency virus (HIV) infection in perinatally infected children in Thailand. METHODS: At 2 large Bangkok hospitals, 295 infants born to HIV-infected mothers were enrolled at birth from November 1992 through September 1994 and followed up with clinical and laboratory evaluations every 1 to 3 months for 18 months. Infected children remained in follow-up thereafter. For the infected children, we used data collected through October 2000 to estimate survival times and compare characteristics among those whose disease progressed at rapid (died within 1 year), intermediate (died at 1-5 years), and slow (survived at least 5 years) rates. RESULTS: None of the 213 uninfected children died during the follow-up period. Of the 68 infected children, 31 (46%) died; median survival was 60 months (95% confidence interval: 31-89 months). The most common cause of death was pneumonia (52% of deaths). Thirty-two children (47%) started antiretroviral therapy. Six children died in their first year before developing specific signs of HIV infection; all others developed signs of HIV infection between 1 and 42 months old (median: 4 months). Severe clinical (Centers for Disease Control and Prevention Class C) conditions were diagnosed in 23 children at a median age of 12 months, 15 (65%) of whom died a median of 3 months later. Compared with children whose disease progressed slowly, those whose disease progressed rapidly gained less weight by 4 months old (median 1.7 vs 2.6 kg), and their mothers had higher viral loads (median 5.1 vs 4.5 log(10) copies/mL) and lower CD4(+) counts (median 350 vs 470 cells/ micro L) at delivery. CONCLUSIONS: Among HIV-infected Thai children, survival times are longer than among children in many African countries, but shorter than among children in the United States and Europe. Signs of HIV develop early in most children. Growth failure and advanced maternal disease can predict rapid HIV disease progression and may be useful markers for treatment decisions.