Prolonged herpes-zoster infection associated with immunosuppressive therapy.

Unusually prolonged zoster was observed in four patients, two with cardiac transplants, one with acute lymphocytic leukemia, and one with diffuse histiocytic lymphoma. Lesions increased in number and persisted for 5 to 24 weeks before beginning to resolve. Specific cellular-immune responsiveness to varicella-zoster virus was markedly depressed during these infections. Absolute numbers of T lymphocytes were also very low. Reducing immunosuppressive therapy to increase immune responses appeared to initiate resolution of zoster lesions and halt dissemination. In one patient treatment with adenine arabinoside was also needed for resolution of disseminated zoster. This syndrome appears to be counterpart of the prolonged mucocutaneous herpes-simplex infection previously reported in immunosuppressed cardiac and renal transplant patients.