[Analysis of new criteria for increasing the specificity of commercial Western blots].

We examined the frequency of serum cross-reactivity on Western blot for HIV1 and HIV2. 661 patients with tuberculosis in Abidjan, and 4,899 asymptomatic persons for HIV1 and HIV2 infections were tested. All specimens positive on ELISA for HIV1 or HIV2 were further characterized by synthetic peptide based tests. Confirmed positive samples were tested by HIV1 and HIV2 specific Western blot criteres utilisis. Dual serologic reactivity on synthetic peptide tests was significantly more frequent in HIV positive patients with tuberculosis than asymptomatic subjects. Positive HIV1 Western blots were seen in 61%-86% of specimens positive for HIV2 only on synthetic peptide tests. [Cross-reactivity, to HIV2 Western blots by HIV1 positive specimens was significantly more frequent in patients with tuberculosis than in asymptomatic subjects.] Using recently recommended criteria for HIV1 and HIV2 Western blot interpretation (presence of 2 env bands) reduced the overall proportion of HIV1 positive specimens having a positive HIV2 Western blot from 39% to 14% and HIV2 positive specimens having a positive HIV1 Western blot from 31% to 8%.