Distribution of HIV-1 subtypes seen in an AIDS clinic in Sao Paulo City, Brazil.

ABSTRACT

PIP: Serum samples from 80 consecutive HIV-1-infected individuals presenting to the Immunodeficiency Clinic at the University of Sao Paulo in 1993 were analyzed to determine the distribution of HIV-1 subtypes in the city. Peripheral blood mononuclear cells (PBMC) were separated using Ficoll-Hypaque gradient, a portion was used for routine CD4 counts, and the rest were frozen. PBMC were proteinase-K-digested and DNA-purified by organic extraction. The samples were amplified for the env region of HIV, and envelope sequence subtypes determined by heteroduplex mobility analysis using prototypic subtypes as references. A subset was also sequenced through the C2-V3 region of env. 69 samples yielded env polymerase chain reaction product enabling subtype determination. The samples which did not amplify had low DNA yields. Among 12 IV-drug users or their sex partners, four were typed as clade F and eight as clade B. 43 homosexual men or female sex partners of bisexual men were typed as clade B. The 14 additional cases with no known risk factor were typed as clade B.