Skin tests with autologous irradiated tumour cells were performed in 20 malignant melanoma, 7 breast and 6 ovarian cancer patients. In the majority of cases evident reaction was noted with cholesteryl hemisuccinate (CHS)-treated cells while the reaction with untreated cells was mostly negative. No correlation was found between this reactivity and the ability of patients to be sensitized to DNCB and to their reactivity to PPD. No correlation was found between reactivity to CHS-treated tumour cells and the stage and course of the disease.

Summary. The percentage of E-rosetteforming cells (E-RFC

Skin tests with autologous cholesteryl hemisuccinate (CHS)-treated and untreated cells were performed in ten metastatic melanoma patients. In the majority of cases evident reaction was noted with CHS-treated cells (9/10) while the reaction with untreated cells was mostly negative (7/10). Tumour cell suspensions used for skin tests were characterized for reactivity with monoclonal antibody TAL 1B5 detecting the HLA-DR alpha chain. There were no differences between CHS-treated and untreated cells with respect to HLA-DR expression and no correlation was found between grade of skin reaction to CHS-treated cells and the proportion of HLA-DR positive cells in the injected cell sample.

Melanoma cells freshly isolated from regional lymph node metastases of 59 stage II malignant melanoma patients were analyzed by indirect immunofluorescence staining with monoclonal antibody TAL 1B5, detecting the HLA-DR alpha chain. The expression of HLA-A,B,C antigens, using antibody W6/32, was also investigated in 45 of these cases. There were no substantial differences in the course of the disease with respect to the percentage of positive cells. In 13 malignant melanoma patients two to four simultaneous and/or successive metastases (both locoregional and distant-subcutaneous) were analysed for HLA-DR. With simultaneous metastases (7 cases) the percentage of HLA-DR-positive cells was mostly very similar, and in no case was there more than 25% variation. As to successive metastases (9 cases) the percentage of HLA-DR-positive cells remained practically unchanged or decreased during the course of the disease.