Identification of CD16/NKH-1+ natural killer cells and their relevance to cutaneous tumour immunity.

The presence of natural killer (NK) cells, as defined by reactivity with the monoclonal antibodies Leu 7, Leu 11 and Leu 19 was assessed in the inflammatory infiltrate around epidermal neoplasms and compared with findings in a range of inflammatory dermatoses. HNK-1+ (Leu 7) cells were present in a wide range of malignant, pre-malignant and inflammatory disorders. Cells positive for the more specific NK cell antigens CD16 (Leu 11)/NKH-1 (Leu 19) had a distribution mainly restricted to cases of squamous cell carcinoma (five of nine) and keratacanthoma (three of seven). The variability in distribution between the different antibodies suggests that the majority of cutaneous HNK-1+ cells are not NK cells, but represent cross-reacting T lymphocytes. The qualitatively distinct distribution of CD16+ and NKH-1+ cells around some cases of squamous cell carcinoma and keratoacanthoma is of interest but their absence from a number of such cases calls into question a specific effector role for natural killer cells in these squamoproliferative tumours.