Immunity in tumours of the skin. Studies on cell-mediated immune reactions.

Cell-mediated immunity (CMI) was investigated in a series of patients with epithelial tumours of the skin and with Kaposi's sarcoma. In all 53 patients the peripheral blood lymphocyte count showed no substantial difference from the control values. The blasts count after phytohaemagglutinin stimulation in 30 patients ranged from 40-50% with no noticeable difference from the control values. Intradermal tests with the staphylococcal antigen, PPD-tuberculin and streptokinase-streptodornase carried out in 59 patients proved negative in a significant number of cases, mainly those of Kaposi's sarcoma. The non immune inflammatory response to chemical irritant (benzalkonium chloride) was more often negative (17 of 59 cases) than in controls (5 of 30 subjects). The DNCB sensitization test carried out in 28 patients was negative in 5 cases (2 cases of late basal-cell epithelioma, 2 cases of advanced squamous-cell carcinoma and 1 case of Kaposi's sarcoma). The findings do not thus indicate the presence of a gross CMI defect in the material studied, which would be borne out by all the tests employed. The sometimes discordant results of the various tests suggest the existence of partial CMI defects in certain tumours, but mainly in Kaposi's sarcoma. Such partial defects, encountered even in early neoplasms, coexist, in some cases, with failure of inflammatory response to chemical irritants.