Disease-free survival rates were determined in HIV-infected hemophiliacs. The effects of co-factors such as intensive transfusion, concomitant cytomegalovirus or chronic NANB hepatitis infection were ascertained. Host-virus interaction was assessed through the use of plasma cultures, specific antibody titers, and markers of immune changes detected by flow cytometry and immune function assays. The immunology of asymptomatic stable infection was investigated. The safety of volunteer donor blood products was determined in seronegative patients exposed to over 50,000 donors yearly and the risk of sexual transmission of HIV to spouses of seropositive patients was monitored.