High concordance between polymerase chain reaction and antibody testing ofspecimens from individuals dually infected with HIV types 1 and 2 in Guinea-Bissau, West Africa

In this study we have evaluated the concordance between serology, using fiv e commercially available antibody assays designed to discriminate between H IV-1 and HIV-2, and the polymerase chain reaction (PCR) for the detection o f HIV-1 and HIV-2 dual infection, Thirty-seven HIV-1 and HIV-2 dually react ive serum samples from individuals in Guinea-Bissau with total CD4(+) rr ly mphocyte counts ranging from 9 to 948 x 10(6)/liter were included in the st udy. All samples were tested by Multispot, Pepti-LAV, and Immunocomb HIV-1 and HIV-2 discriminatory antibody assays. Thirty-two of the 37 samples were also tested by a combination of two HIV type-specific antibody enzyme-link ed immunosorbent assays (ELISA; Wellcozyme HIV-1 and Murex HIV-2). Each sam ple showed dual reactivity in all or any of these assays. A nested PCR base d on primer systems in the vif and pol regions of HIV-1 and in the gag and LTR regions of HIV-2 was used to evaluate the serological results, Thirty s amples from HIV-1 antibody-positive individuals and 30 samples from HIV-2 a ntibody-positive individuals were all PCR positive with their corresponding primer systems, The type specificity was 100% for all of the primer system s, The concordance between dual HIV-1 and HIV-2 reactivity on the serologic al assays and PCR was 77.7% for Multispot, 80% for Pepti-LAV, 81.8% for Imm unocomb, and 85.7% for the two ELISAs used in combination. Thus the majorit y of individuals included in this study appeared to be truly dually infecte d, The study shows that it is possible, through a careful selection of assa ys, to reach a high concordance between serological assays and PCR in study ing HIV-1 and HIV-2 dual infections.