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 memory/ effector T cells to chronic inflammatory sites in skin. Here, we examine 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 neoplasms metastatic to cutaneous and noncutaneous sites were immunostained with anti-CLA (HECA-452), as well as antibodies directed against B cells (CD20), T/NK cells (CD43), and memory/effector T cells (CD45RO). Essentially all of the lymphocytes surrounding and infiltrating both the cutaneous and noncutaneous tumors were CD43+/CD20-, and most expressed the memory/effector marker CD45RO. CLA was expressed on 10 to 80% (mean: 50%) of T cells associated with primary cutaneous neoplasms (including both melanomas and squamous cell carcinomas) but was essentially absent from noncutaneous primaries (including those metastatic to dermis) and from cutaneous primaries metastatic to dermis or other sites. 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-specific mechanisms. The lack of a CLA + T-cell response to dermal metastases suggests that epidermal involvement may be required to attract this subset.