Correlates of Nontransmission in U.S. Women at High Risk of Human Immunodeficiency Virus Type 1 Infection through Sexual Exposure [Skurnick JH et al. JID 2002;185:428] The authors performed extensive laboratory-based studies on 17 women who were persistently seronegative for HIV infection despite repeated sexual exposure. Most were discordant couples with unprotected sexual exposure 10-30 times/month with a median follow-up period of 4 years. There were also 12 male HIV-infected partners who were studied. Most of these patients were identified before HAART, and only two of the male patients were receiving triple therapy. Of interest is the observation that 6 of the 12 men had viral loads <1,000 c/ml, and only two had viral loads >23,000 c/ml. With regard to the 17 women, 13 had at least one immune response to HIV-1 specific CD8 cell response, and this was also seen in all 8 male partners who were tested. The authors conclude that HIV-1 specific CD8 cell activity is an important protective factor.
Comment: This is a potentially very important study in terms of understanding apparent protection despite repeated exposure to HIV and it also has important implications for vaccine development. Of particular importance and possibly surprising is the demonstration of the contribution of the HIV-positive donor to nontransmission that may be related to the high CD8 cell count and the HIV-specific CD8 mediated response. The latter was also demonstrated in 11 of 17 of the women participants.
posted 3/05/2002

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