Immune responses in cardiac transplantation. I. Detection of activated TIa+ cells in the blood during herpes virus infections.

Lymphocyte subpopulations in the blood of cardiac transplant recipients were monitored by single and double marker rosetting tests; using monoclonal antibodies to monomorphic determinants on T cells and 'Ia' antigens. Elevated absolute numbers and percentages of TIa+ cells were found in association with primary cytomegalovirus (CMV), and reactivation of Epstein-Barr virus or Herpes simplex virus. Serial tests showed that in primary CMV TIa+ cells peaked before the maximal IgM and IgG anti-viral titres measured by ELISA. Infection related antiglobulin levels increased in parallel with anti-viral IgM in primary CMV infections. Intravenous methylprednisone and blood transfusions selectively depressed TIa+ cell levels without affecting antibody titres. These results show that patients on maintenance immunosuppression of cyclosporin A and steroids can successfully mount T cell and antibody responses to herpes virus infections.