Identifying HIV-2-seropositive individuals by reevaluating HIV-1 indeterminate sera.

HIV-2 infections are rare in North America, with less than 30 cases identified since 1988. We conducted a surveillance for HIV-2 seroprevalence by re-evaluating 457 HIV-1 indeterminate serology specimens submitted to the Maryland Department of Health Laboratories from January 1, 1988 to July 15, 1991. All indeterminates were screened using a combination HIV-1/HIV-2 synthetic peptide EIA. The presence of HIV-2-specific antibodies in initially reactive sera was confirmed utilizing a selective HIV-2 synthetic peptide EIA and Western blotting. Eight sera from four adult males attending public health clinics in suburban Washington, D.C. were found to be specifically reactive for HIV-2 antibodies. One is a native West African; the others remain anonymous. All eight sera demonstrated a gag (core) and pol (polymerase) only pattern of reactivity on HIV-1 Western blots. Targeting selected groups of HIV-1 indeterminate sera from patients attending public health clinics may represent a more appropriate strategy to monitor the spread of HIV-2 in North America than testing similar samples from the blood donor population.