HIV-2 antibody detection after indeterminate or negative HIV-1 Western blot in Cuba, 2005-2008

introduction differentiating between hiv-1 and hiv-2 infection is the first step to understanding hiv transmission, epidemiology and pathogenesis in geographical areas where both viruses circulate. in cuba, positive results in mixed hiv-1/2 screening assays are confirmed by hiv-1 western blot. indeterminate results constitute the main limitation of this test and hiv-2 infection is among their possible causes; hence the importance of second-stage screening and confirmatory tests for hiv-2 infection. objective investigate the contribution of hiv-2 antibodies to negative or indeterminate hiv-1 western blot results in serum samples from 2005 through 2008 in cuba. methods hiv-2 reactivity was studied using the elisa davih-vih-2 diagnostic kit (cuba) in 1723 serum samples with negative or indeterminate results for hiv-1 western blot from january 2005 through december 2008. duplicate sera reactive by elisa were confirmed by hiv-2 western blot, results interpreted according to who criteria. the epidemiological interview established by cuba's national program for prevention and control sexually-transmitted diseases and hiv/aids was applied to hiv-2 western blot-positive patients. results among all sera studied, hiv-2 elisa identified 12 reactive serum samples (0.70%) and 1711 non-reactive (99.30%). western blot analysis of the 12 elisa-reactive samples confirmed two positive samples (16.67%), 4 negative (33.33%) and 6 indeterminate (50%). positive samples reacted against the p16, p26, gp36, p53, p56, p68 and gp105 proteins. all 12 elisa-reactive samples belonged to the hiv-1 western blot indeterminate group. the two hiv-2-positive samples showed well defined reactivity to gp160, p53, p55 and p34 of hiv-1. hiv-1 seroconversion was observed in all 10 remaining samples during serological followup. conclusions two new hiv-2 seropositive cases were diagnosed using davih-vih-2 and hiv-2 western blot in indeterminate hiv-1 western blot samples. results support the recommendation th