Immunologic hemophilia A abnormalities in patients with To assess the immunologic status of healthy persons with hemophilia ,4, we performed studies of T cell immunity in 21 patients, 10 given only cryoprecipitate and 11 given factor VIII concentrate. Patients in the factor VIII group had significantly decreased helper/suppressor T cell ratios. Both groups had diminished mononuclear cell response to phytohemagglutinin and normal mixed lymphocyte culture, compared with controls. Abnormalities in T cell number or function did not correlate with the presence of antibody to cytomegalovirus, Epstein-Barr virus, or hepatitis B. Physicians caring for patients with hemophilia ,4 should realize that asymptomatic individuals may have early evidence of immunodeficiency. (J PEDIATI~ 103:692, 1983) Peggy S. Weintrub, M.D., Marion A. Koerper, M.D., Joseph E. Addiego, Jr., M.D., W. Lawrence Drew, M.D., Ph.D., Evelyn T. Lennette, Ph.D., Richard Miner, B.A., Morton J. Cowan, M.D., and Arthur J. Ammann, M.D. San Francisco and Oakland, Calif. THREE PATIENTS WITH HEMOPHILIA A, receiving fac- tor VIII concentrate, have been reported who developed Pneumocystis carinii pneumonia and acquired immunode- ficiency syndrome? Infections with opportunistic patho- gens have not previously been recognized in this popula- tion, and therefore concerns have been raised that therapy might result in AIDS. In the current epidemic of AIDS in homosexual men, Haitians, and drug addicts, studies of the immune system have shown abnormalities in these groups, including cutaneous anergy, lymphopenia, decreased num- bers of T cells, reduced helper/suppressor T cell ratios, and depressed proliferative responses of peripheral blood mononuclear cells to mitogens, antigens, and allogeneic cells. 2-4 Apparently healthy homosexuals also have evi- dence of immunologic dysregulation, but to a lesser degree From the Divisions of Pediatric Immunology-Rheumatology and Hematology-Oncology, University of California, San Francisco, the Department of Hematology-Oncology, Children's Hospital Medical Center, and the Department of Pathology and Laborato- ry Medicine. Mt. Zion Hospital and Medical Center. Supported by grants from the National Hemophilia Foundation, Judith Graham Pool Post-Graduate Rd'~e~rch Fellowship, Immu- nology Research Foundation, Clinical Research Center Grant RRO1271-O1, and the John Kerner Fund, Mt. Zion Hospital and Medical Center. Reprint requests: Arthur J. Ammann, M.D., Pediatric lmmunol- ogy-Rheumatology, M-679, University of California, San Fran- cisco, San Francisco, CA 94143. than those with clinical evidence of disease? ,6 To deter- mine whether apparently healthy patients with hemophilia A have laboratory evidence of AIDS, we performed studies of T cell immunity in 21 patients. See related article, 103:18, 1983. AIDS EBNA EBV Hb~Ag HBSS HBV MLC PBMC VCA Acquired immune deficiency syndrome Epstein-Barr nuclear antigen Epstein-Barr virus ,,Hepatitis B surface antigen Hanks Balanced Salts Solution Hepatitis B virus Mixed lymphocyte culture Peripheral blood mononuclear cells Viral capsid antigen ,METHODS Patients were from the hematology clinics of the Univer- sity of California, San Francisco, and the Children's Hospital Medical Center, Oakland, California. Twenty- one healthy prepubescent or heterosexual males with hemophilia A were evaluated. The patients were divided into two groups: those given only cryoprecipitate (10 patients) and those given factor VIII concentrate (11 patients), many of whom had received prior cryoprecipi- 692 TheJournalofPEDIATRICS