Characterization of mononuclear cells in the inflammatory infiltrates of cutaneous tumours

The identification of mononuclear cells extracted from cutaneous tumours (basal cell carcinoma, squamous cell carcinoma and superficial, spreading melanoma) has been investigated. The relative numbers of T cells and B cells have been determined using the E-rosette test and the EAC-rosette test. The results have been compared to those of delayed hypersensitivity type reactions. Different cell distribution patterns (E/EAC ratio) have been found in the infiltrates according to the type of tumour. An immunocytochemical technique has been developed for the identification in situ of immunoglobulin-producing cells in the inflammatory infiltrates. In each case the class of immunoglobulin (IgM, IgG or IgA) has been identified and the relative frequency of Ig-producing cells has been determined. The results indicate humoral and cellular immune responses with variations attributable to the type of tumour. In weakly malignant tumours, the infiltrate is characterized by an elevated number of T lymphocytes and numerous plasma cells which secrete all classes of Ig; in highly malignant tumours it is characterized by a reduced number of both T lymphocytes (E rosette) and plasma cells which do not secrete all classes of Ig.