Cytomegalovirus infection in patients receiving immunosuppressive therapy for rheumatologic disorders.

Evidence of cytomegalovirus infection was sought in 131 patients attending a rheumatology clinic, 211 blood donors, and 14 patients before and after the initiation of cytotoxic immunosuppressive therapy for a rheumatologic condition. The titer of complement-fixing antibody to cytomegalovirus was significantly related to age and sex, but not to rheumatologic disease. After adjustment for age and sex differences, the proportion of patients treated with corticosteroids who had measurable antibody was lower than that of controls (P less than 0.025). Immunosuppressive therapy with azathioprine or cyclophosphamide did not affect the proportion of patients with antibody, but there was a significantly increased titer of antibody in those who were seropositive (P = 0.04). Cytomegalovirus was isolated from the urine of 20% of patients receiving cytotoxic immunosuppressive drugs, but not from any of the patients receiving corticosteroids or neither form of therapy (P = 0.001). Eight of 14 patients followed prospectively after the initiation of therapy with immunosuppressive drugs became infected with cytomegalovirus as demonstrated by a fourfold or greater rise in complement-fixing titer, viruria, or both. Seven of the eight patients were seropositive before therapy, a finding suggesting that immunosuppression acts largely by reactivating latent infection. It is postulated that immunosuppressive agents alone may account for a large proportion of cytomegalovirus infections seen after allograft transplantation.