HIV isolation and antigen detection in infected individuals and their seronegative sexual partners.

We have examined 39 couples, each consisting of one HIV-seropositive index case and one seronegative sexual partner. HIV isolations, HIV antigen (HIV-Ag) tests and HIV antibody tests were performed on samples from these 78 individuals. Results were compared with those of 68 unselected individuals. Neither HIV, nor HIV-Ag was detected in any of the seronegative individuals. HIV-Ag tests, but not HIV isolations showed positive results with a significantly lower frequency in symptomatic index cases than in unselected patients with symptoms. This indicates that the absence of HIV-Ag in the serum may be correlated with a low level of contagiousness.