The authors studied the immune status of 14 HIV-infected patients, 6 of whom had lymphadenopathy, 4 were diagnosed as having AIDS-related complex and 4, a full-blown AIDS. Analysis of laboratory findings showed that of predictive value are serum levels of immunoglobulin B, a CD4 cell count less than 200, reduced populations of CD20 and CD16 lymphocytes, and a depressed response to pokeweed mitogen. Based on the clinical manifestations and laboratory results, three stages characterizing the immune system in HIV infection have been identified.