HIV type 1 subtypes in Malaysia, determined with serologic assays: 1992-1996

We investigated the molecular epidemiology of HIV-1 subtypes in Malaysia am ong injecting drug users (IDUs) and sexual transmission risk groups, using serologic and genetic techniques. Frozen sera collected at a general hospit al, a blood bank, several drug treatment centers, and an STD clinic in Kual a Lumpur, between 1992 and 1996, were investigated retrospectively. V3 pept ide serotyping and monomeric gp120 capture serotyping were used to study 89 known HIV-l-infected subjects. The methods differentiate subtypes B, E, an d C, V3 peptide and gp120 capture results were comparable. No subtype C-spe cific reactive sera were found; one specimen was dually reactive for subtyp es C and B, using the V3 peptide ELISA; and four were durally reactive for subtypes E and C using this assay. Genotypic analysis of HIV-1 gag RNA in s erum was done on a subset of subjects and confirmed serologic findings, HIV -1 subtypes differed significantly by risk category: of 53 IDUs, 29 (55%) w ere infected with subtype B and 19 (36%) were infected with subtype E, 3 (6 %) were dually reactive, and 2 (4%) were not typable, Of 36 persons with he terosexual risks, 29 (81%) were infected with subtype E, 5 (14%) were infec ted with subtype B, and 2 (5%) were not typable, Persons with IDU risks wer e significantly more likely to be infected with subtype B than were those w ith sexual risks (OR 5.89; 95% CI, 1.94-18.54; p < 0.001). Subtypes B and E of HIV-1 appear to predominate in Malaysia; subtype B was more prevalent a mong IDUs; subtype E was more prevalent among all other groups. These resul ts may have important HIV-1 vaccine implications.