861 HIV-stimulated IL-2 Production among Exposed-uninfected Infants of HIV-infected Mothers Given Nevirapine Prophylaxis L. Kuhn*1, S. Meddows-Taylor2, G. Gray3, D. Schramm2, C. Tiemessen2 1Columbia Univ, New York, NY; 2Natl Inst of Communicable Diseases, Johannesburg, South Africa; and 3Chris Hani Baragwanath Hosp, Soweto, South Africa
Background: A single dose of nevirapine to an HIV-infected woman at the onset of labor followed by a single dose to the infant shortly after birth has been shown to be effective in reducing perinatal HIV transmission. How this regimen achieves reductions in transmission is unclear.
Methods: As part of a study to investigate immunologic responses among infants born to HIV-infected mothers, cord blood was collected from 25 deliveries in which nevirapine was given at the onset of labor and from 115 deliveries in which no antiretroviral drugs were given. The latter were collected from a study evaluating post-exposure prophylaxis for infants of HIV+ women not identified as positive before delivery. Cord blood from 20 HIV- women were collected as controls. Cord blood cells were stimulated with HIV envelope peptides and IL-2 production was measured using the Quantiglo immunoassay (R&D, Oxon, UK). Responses were considered present if IL-2 production among HIV-stimulated was > 3x unstimulated cultures.
Results: HIV-stimulated IL-2 production was detected among 18/115 (16%) deliveries if no antiretroviral drugs were given prior to birth, but among 0/25 deliveries if nevirapine was given (p = 0.03). No HIV-stimulated responses were detected among HIV- control deliveries. Similar results were obtained if analysis was restricted to those deliveries in which the infant was confirmed to be uninfected. Maternal plasma viral load at delivery was similar among those with (mean 4.23 log10 copies/ml) or without (4.11 log10 copies/ml) HIV-stimulated responses. Maternal CD4 counts were also similar (mean 479 vs 541) among those with vs without HIV-stimulated IL-2 responses.
Conclusion: Single-dose nevirapine given shortly before birth may have immunologic consequences detectable in cord blood. Further characterization of these consequences may help identify how single dose nevirapine is effective in reducing perinatal HIV transmission. Studies of newborn immune responses to HIV need to take into consideration use of antiretroviral drugs prior to birth.
