Cell-mediated immunity to cytomegalovirus in immunocompromised patients: effect of radiation or chemotherapy.

Using the techniques of complement fixation, immunofluorescence, and in vitro lymphocyte transformation (LTF), we studied the humoral antibody and cell-mediated immunity to cytomegalovirus (CMV) in normal subjects, in patients with cancer receiving localized or nonlocalized radiation, and in renal transplant recipients on immunosuppressive chemotherapy. The LTF activity was determined by the whole blood microassay, using four strains of CMV (AD-169, Davis, Veca, and Towne), AD-169 early antigen, and phytohemagglutinin (PAH). The renal transplant subjects manifested significantly depressed LTF responses to PHA and CMV and frequent presence of immunoglobulin M and early antigen-specific antibody response. The depressed LTF response to CMV recovered significantly 2 years after transplantation. The cancer patients were also characterized by a profound drop in LTF responses to PHA and CMV and in immunoglobulin M and early antigen-specific antibody response after nonlocalized radiation. LTF responses to AD-169 and Towne strains were found to be higher than those to Davis and Veca strains. The LTF response to PHA declined with age. However, LTF responses to specific CMV antigens were found to be somewhat increased with advancing age. These observations suggest that transplantation-associated suppression of CMV-specific cell-mediated immunity may improve a few years after transplantation despite continued immunosuppressive therapy.