Patients with genetic defects associated with depressed cell mediated immunity (CMI) [16,21], etc.) have an increased susceptibility to development of multiple, treatment-resistant warts. Patients who have been inadvertently immunosuppressed by chemotherapeutic drugs, used for malignancies, also have increased wart and skin cancer incidence [20], as do patients who have been purposely immunosuppressed for treatment of auto-or hyperimmune diseases, such as lupus erythematosus [7,20]. Patients who are immunosuppressed over long periods of time to enhance retention of organ transplants, such as renal allograft recipients, also have a high incidence of warts and skin cancers [3,4,7,8,17,20,25]. The cancer incidence in these patients seems to be proportional to the period of immunosup-(