Epidemiologic and biologic characterization of a cohort of human immunodeficiency virus type I highly exposed, persistently seronegative female sex workers in northern Thailand

Characterization of persons highly exposed to human immunodeficiency virus (HIV)-1 who remain uninfected may help define protective immunity Seventeen HIV-l-seronegative Thai female sex workers (CSWs) with epidemiologic evide nce of exposure to HIV-1 were studied for humoral immune responses and phen otypic and genotypic analyses of HLA class I and CCR5 allelic profiles. Inf ected CSWs and low-risk HIV-l-seronegative Thai women were controls. Highly exposed, persistently seronegative (HEPS) CSWs did not differ from HIV-inf ected CSWs in HIV risks, condom use, or sexually transmitted diseases. Sign ificant differences were seen in humoral immune responses: gp160-specific I gA responses were detected in cervicovaginal lavage fluids in 6 of 13 HEPS CSWs but 0 of 21 seronegative subjects. All women had wild-type CCR5, HEPS CSWs were more likely to have the HLA-B18 phenotype and genotype than were matched controls (corrected P=.018), Epidemiologic exposure to HIV-1 withou t apparent infection, an unusual distribution of HLA class I alleles, and H IV-1 gp160-specific IgA responses suggest a biologic basis for this phenome non.