Human leukocyte antigen B distribution in HIV discordant cohort from India.

Limited reports are available on association of HLA-B with HIV infection from India, a home to the third largest population of HIV infected people in the world. This emphasizes the need to have more information specifically the genetic constitution of HIV serodiscordant couples (DCs), where one spouse is seropositive (HSP) while the other remains seronegative (HSN) even after repeated exposure. Hence, aim of this study was to document association of HLA-B with HIV infection in DCs living in Mumbai, India. A cohort was designed to enroll DCs attending the ICTC/Shakti Clinic of KEM Hospital, Mumbai. A group of unexposed volunteers were also enrolled as healthy controls (HC). HLA-B alleles were typed using sequence-specific oligonucleotide probes. Allele frequency comparison was done using 2×2 contingency tables. Results were considered significant, when p<0.05 with two-tailed Fisher's exact test. At HLA-B locus, the frequencies of HLA-B*40;-B*35;-B*07;-B*15;-B*51;-B*44;-B*52;-B*37 and -B*57 were found in decreasing order in the population. Frequency of HLA-B*35 allele was significantly higher (HSP vs HSN; p<0.02 and HSP vs HC; p<0.04) in HSP. HLA-B*40 (HSN vs HSP; p<0.01 and HC vs HSP; p<0.01) and HLA-B*18 (HSN vs HSP; p<0.02) were significantly associated with HSN. Both HSN and HC had similar HLA-B*35 and -B*40 allele frequency. HLA-B*57 allele was observed in 15 individuals (3.69%). However, HLA-B*57:01 which is known to be associated with adverse reactions against Abacavir was observed in 7 of them. HLA-B*39 was observed exclusively in HSP. Our observation in DCs confirmed the association of HLA-B*35 with susceptibility while HLA-B*40 (specifically *B40:06), -B*18 with protection. These identified alleles can be used as possible marker associated with HIV transmission. In India, HLA screening is not carried out before initiation of HIV treatment. However, the presence of HLA-B*57:01 in the population emphasizes the importance of such screening to predict/avoid Abacavir hypersensitivity.

Antiretroviral treatment, viral load of mothers & perinatal HIV transmission in Mumbai, India.

BACKGROUND & OBJECTIVES: Mother-to-child transmission (MTCT) is the most significant route of HIV transmission in children below the age of 15 yr. In India, perinatal HIV transmission, even after treatment, accounts for 5.4 per cent of HIV cases. The present study was conducted to evaluate the efficacy of anti-retro viral therapy (ART) or prophylactic treatment (PT) to control maternal viral load in HIV positive women, and its effect on vertical HIV transmission to their infants. METHODS: A total of 58 HIV positive women were enrolled at the time of delivery and their plasma samples were obtained within 24 h of delivery for estimation of viral load. Viral load analysis was completed in 38 women. Infants received single dose nevirapine within 2 h of birth and zidovudine for 6 wk. At the end of 18 month follow up, HIV positive or negative status was available in 28 infants. RESULTS: Results revealed undetectable levels of viral load in 58.3 per cent of women with ART compared to 30.7 per cent of women with PT. No women on ART had viral load more than 10,000 copies/ml, whereas seven (26.9%, P=0.07) women receiving PT had this viral load. Median CD4 count of women on PT (483 cells/µl) was high compared to the women on ART (289 cells/ µl). At the end of 18 months follow up, only two children were HIV positive, whose mothers were on PT. One had in utero transmission; infection detected within 48 h of delivery, while the other child was infected post partum as HIV was detected at six months follow up. INTERPRETATION & CONCLUSIONS: Women who received a single dose of nevirapine during delivery had higher levels of viral load than women on ART. Combination drug therapy for pregnant women is now a standard of care in most of the western countries; use of nevirapine monotherapy at the time of delivery in our settings is not effective in controlling viral load. This highlights initiation of ART in pregnant women to control their viral load and thus to inhibit mother to child HIV transmission.