Comparison of 10 enzyme immunoassays for detection of antibody to human immunodeficiency virus type 2 in West African sera.

The efficacy of 10 enzyme immunoassays (EIAs) for antibody to human immunodeficiency virus type 1 (HIV-1) in detecting antibody to HIV-2 was evaluated in sera from 43 West African residents. 23 sera were from asymptomatic individuals belonging to high-risk groups (prostitutes, prisoners, patients with sexually transmitted diseases), while the remaining 20 serum samples were from persons with symptoms of acquired immunodeficiency syndrome (AIDS). The overall prevalence of positive results was 28-51% with the competitive EIAs and 70-93% with the indirect EIAs. Most of the EIAs were less sensitive in detecting antibody to HIV-2 in sera from people with AIDS-like disease compared with asymptomatic individuals. This study shows that commercial HIV-1 antibody test kits are not equally efficient in detecting HIV-2-antibody-positive sera. Cross-reacting HIV-2 antibodies seem not to have enough affinity to compete with the anti-HIV-1 conjugate. Given the high degree of cross-reactivity between HIV-1 and 2 by EIA, serotype specificity must be determined by Western blot with both sets of viral antigens. In areas such as the Ivory Coast where HIV-2 is prevalent, these findings must be taken into consideration in the screening of blood donors.