CORRELATION OF GENETIC AND SEROLOGIC APPROACHES TO HIV-1 SUBTYPING INTHAILAND

The aim of this study was to compare the performance of differential p olymerase chain reaction (PCR) typing and peptide enzyme-linked immuno sorbent assay (V3-EIA) for human immunodeficiency virus type 1 (HIV-1) subtyping in Thailand using heteroduplex mobility assay (HMA) as the reference standard. Paired peripheral blood mononuclear cells (PBMC) a nd sera were collected from 38 HIV-1 seropositive persons in Thailand. HMA was done by standard methods; differential PCR employs primer pai rs that differentially amplify either subtype E or B. V3-EIA used pept ides specific for subtypes E or B. Thirty-two eases (84%) were found b y HMA to be infected with subtype E and six with (16%) subtype B. The results obtained with differential PCR were 100% concordant with those of HMA; V3 EIA correctly predicted the subtype in 95% (36 of 38). Six samples that molecularly subtyped as E. were repeatedly dual reactive by screening V3-EIA, but these resolved to subtype E using an antigen -limiting EIA, Two samples were serologically nontypeable because of o verall low levels of V3 antibody. Using HMA as the standard, different ial PCR was shown to subtype HIV-1 reliably from patient PBMC samples. V3-EIA correctly predicted HIV-1 subtype in most (95%) of our cases. Because of tile less rigorous sampling requirements, specimen processi ng, and logistical and technical requirements of serotyping compared w ith molecular techniques, it appears to be practical for screening pur poses in a field environment. Samples that cannot be definitively subt yped serologically should undergo differential PCR and antigen-limitin g V3 ELA. These approaches to HIV-1 subtyping should be used in comple mentary fashion in Thailand, where subtypes B and E are currently know n to cocirculate.