National case-control study of Kaposi's sarcoma and Pneumocystis carinii pneumonia in homosexual men: Part 2. Laboratory results.

The Centers for Disease Control conducted a case-control study to investigate an outbreak of Kaposi's sarcoma and Pneumocystis carinii pneumonia in homosexual men. The occurrence of these diseases was found to be associated with certain aspects of lifestyle, including a greater number of male sex partners per year, exposure to feces during sex, history of syphilis and non-B hepatitis, treatment for enteric parasites, and use of various illicit substances. Laboratory studies reflected both this lifestyle and the probable underlying cause of the Kaposi's sarcoma and P. carinii pneumonia--cellular immune deficiency. Patients were found to have lymphopenia, specifically a deficiency of the T-helper subpopulation, resulting in a reversal of the T-helper to T-suppressor ratio. Levels of IgG and IgA were increased. When compared with controls, patients were also found to have significantly higher titers of antibody to Epstein-Barr virus and cytomegalovirus, a higher prevalence of antibody to hepatitis A virus and Treponema pallidum, a lower prevalence of antibody to varicella zoster virus, and a higher frequency of isolation of cytomegalovirus.