IMMUNE-ASSOCIATED CELLS IN BASAL-CELL CARCINOMAS OF SKIN

Increased numbers of mast cells (MCs) and lymphocytes infiltrating in basal cell carcinomas (BCCs) have been observed. The presence of these infiltrating cells has been considered a sign of an immunologic anti- tumor response in the host, but the relationship of these two cell pop ulations has not been examined. To elucidate this possible relationshi p, 30 non-ulcerated BCCs were analyzed. Frozen sections of the tumors were stained with monoclonal antibodies for Langerhans' cells, lymphoc yte subsets and natural killer cells. Fluorescein isothiocynate (FITC) -avidin as well as anti-tryptase and anti-CD45RO monoclonal antibodie s were used on formalin-fixed, paraffin-embedded sections for mast cel l and T cell identification, respectively. B cells and natural killer cells were rarely observed in these tumors. MCs and T cells were quant ified by direct enumeration and expressed as number of cells per high power field (hpf). FITC-avidin and anti-tryptase antibodies were equiv alent in their ability to identify MCs. MC content in BCCs ranged from 1.0 to 31 cells/hpf. The number of T cells ranged from 0 to 50 cells/ hpf with helper/suppressor cell ratios of 0.2 to 10. There was no corr elation between helper/suppressor ratios and mast cell numbers; howeve r, an inverse relationship was observed between the numbers ofT cells and the number of mast cells in these tumors. These studies indicate t hat T cells and MCs are the primary immune cell populations responding to BCCs, and that decreased numbers ofT cells are associated with mor e aggressive tumors.