Membrane properties of infiltrating mononuclear cells in melanocytic lesions were studied. In frozen sections of six primary melanomas and six halo nevi, the infiltrating cells lacked C3 receptors characteristic of B cells and IgG receptors characteristic of histiocytes. Viable infiltrating cells extracted from two primary melanomas formed rosettes with sheep erythrocytes, providing direct evidence of their T cell identity. In contrast, the majority of cells infiltrating melanoma metastases in four patients were identified as histiocytes by their IgG receptors and ultrastructural appearance. Focal aggregates of B cells and plasma cells were found in a giant pigmented nevus in areas of disrupted nevus cells. This suggests a B cell mediated response against nevus-associated antigens, possibly involving antibody dependent target cell lysis. It appears that a spectrum of cellular reactions to melanocytic lesions occurs in vivo and that the type of infiltrating mononuclear cell is related to the type of lesion.
ASJC Scopus subject areas
- Immunology and Allergy
- Pathology and Forensic Medicine