“…None had evidence of HIV-1,2 infection, as judged by multiple serologies over several years, standard viral co-cultures for HIV p24 Gag antigen, and proviral DNA simplification by polymerase chain reaction' (Laurence et al, 1992). Similar cases have recently been reported from other institutions including the CDC (Afrasiabi et al, 1986;Pankhurst & Peakman, 1989;Safai et al, 1991;Seligmann et al, 1991;Sirianni et al, 1991;CDC, 1992;Hi'shida et al, 1992;Tijhuis et al, 1993).…”