Recall antigen delayed-type hypersensitivity skin testing in melanoma and acute leukemia patients and their associates

Patients with malignant melanoma and acute leukemia and their relatives and other associates were screened as potential transfer factor donors and recipients with a battery of four recall, delayed-type hypersensitivity skin test antigens. The skin test results of 336 associates and 179 patients were compared by a variety of techniques, including converting the response in mm to a response score of 0 to 3. There was considerable variation in the response of the associates, 5% being anergic. There was a significant age variation in response to dermatophytin, streptokinase-streptodornase, and Candida (both increases and decreases with age) while purified protein derivative showed no such variation. Taking age into account, the response of Stage IV melanoma patients and acute leukemia patients was lower than that of the normal subjects, while the Stage III melanoma patients had slightly greater responses than did the normals. The antigens most useful in differentiating between groups were Candida and dermatophytin, as well as an overall index of response which reflected the level of response to all the antigens. In a matched comparison of patients and their spouses, the same trends were evident. Comparison of melanoma patients' siblings to other associate groups identified the siblings as low responders. This difference was highly significant for the index of overall response. This was not seen in siblings of leukemia patients. The importance of a well-matched control group of normal subjects for immunological studies of delayed-type hypersensitivity in cancer patients is discussed. Utilization of nonage and nonenvironment-matched controls is to be discouracied.