LYMPHOCYTES INFILTRATING PRIMARY CUTANEOUS NEOPLASMS SELECTIVELY EXPRESS THE CUTANEOUS LYMPHOCYTE-ASSOCIATED ANTIGEN (CLA)

The cutaneous lymphocyte-associated antigen (CLA) is the T-cell ligand for E-selectin and is involved in tissue selective migration of memor y/effector T cells to chronic inflammatory sites in skin. Here, we exa mine the hypothesis that CLA is also involved in the local host immune response to cutaneous neoplasms. Eleven primary cutaneous melanomas, nine primary cutaneous squamous cell carcinomas, and 11 assorted neopl asms metastatic to cutaneous and noncutaneous sites were immunostained with anti-CLA (HECA-452), as well as antibodies directed against B ce lls (CD20), T/NK cells (CD43), and memory/effector T cells (CD45RO). E ssentially all of the lymphocytes surrounding and infiltrating both th e cutaneous and noncutaneous tumors were CD43 +/CD20-, and most expres sed the memory/effector marker CD45RO. CLA was expressed on 10 to 80% (mean: 50%) of T cells associated with primary cutaneous neoplasms (in cluding both melanomas and squamous cell carcinomas) but was essential ly absent from noncutaneous primaries (including those metastatic to d ermis) and from cutaneous primaries metastatic to dermis or other site s. Overall, the results suggest that CLA + memory T cells are a major component of the local host immune response to cutaneous neoplasms and are likely recruited to the skin by site-specific rather than tumor-s pecific mechanisms. The lack of a CLA + T-cell response to dermal meta stases suggests that epidermal involvement may be required to attract this subset.