51   "Resistance Factors" in Highly Exposed Persistently Seronegative (HEPS) Women Married to HIV-Infected Men in Chiang Mai, Thailand.

A. Duerr*¹, C. Costello¹, V. Suriyanon², V. Robison³, and the Thai Couples HEPS Group⁴.
¹CDC, Atlanta, GA;²Chiang Mai Univ., Thailand;³Johns Hopkins Univ., Baltimore, MD; and⁴CONRAD, Arlington, VA.

Background:Factors associated with apparent HIV resistance are most often studied in commercial sex workers whose true exposure to HIV is unknown. We studied resistance in women, who had exposure to a single partner, selected from a couples study of HIV-infected (HIV⁺) Thai male blood donors and their wives.

Methods:12 HIV-uninfected (HIV^-) women with no known HIV exposure were selected as controls. 23 HIV^-women with>2 years of unprotected sexual exposure to a documented HIV⁺man were selected as HEPS. 15 HIV⁺women infected within 1 year of sexual debut were selected as rapid seroconverters (RS). Blood and cervicovaginal lavage (CVL) fluid were collected from all women; blood and semen were collected from husbands of HEPS and RS women.

Results:Plasma and CVL fluid from all HEPS were HIV-negative by serology; plasma from all HEPS was PCR negative. PBMC from all HEPS were susceptible to infection by SI and NSI HIV (subtypes B and E) and, when available, to virus isolated from their husbands' plasma. Factors which did not differ consistently between the HEPS and RS included seminal viral load, defects in seminal HIV accessory genes, HLA class I alleles, co- receptor use by HIV isolated from husband's plasma, CCR5d32 and presence of SLPI in CVL. HIV-specific activity in an IFN-gELISPOT assay was found in 0/12 controls, 11/21 (53%) HEPS and 6/6 (100%) RS. Of the HEPS evaluated, all showed elevated production of novel CD4/CD14-associated suppressive activity.

Conclusions:In this preliminary analysis of a well-documented group of HIV-uninfected women with high level sexual exposure to HIV subtype E, we find only evidence of cell-mediated immunity and soluble suppressor factors.