The T-Cell Chemokine Receptor CXCR3 Is Expressed Highly in Low-Grade Mycosis Fungoides

Three chemokines, Mig, IP-10, and I-TAC, are expressed highly in the epidermis. We examined the expression of the receptor for these chemokines, CXCR3, in cutaneous T-cell lymphoma. We compared CXCR3 expression with that of cutaneous lymphocyte antigen (CLA) and the activation marker CD30. CXCR3 was expressed by at least a subset of tumor lymphocytes in all 25 cases of low-grade mycosis fungoides (MF), with most cells positive in 20 cases. In progressed or transformed MF, CXCR3 expression was noted in 5 of 22 cases. In 4 of 5 MF cases with sequential biopsy specimens, large cell transformation was accompanied by loss of CXCR3 expression. In contrast, CLA was expressed in 35 of 42 MF cases with no significant differences in expression level between low-grade and transformed cases. In other lymphomas, CXCR3 was expressed in 4 of 4 cases of lymphomatoid papulosis, 3 of 4 cases of CD8+ cutaneous T-cell lymphoma, and 3 of 6 cases of systemic T-cell lymphoma in skin, but not in 10 cases of cutaneous anaplastic large cell lymphoma. CXCR3 expression was associated with epidermotropic T-cell tumors but was largely absent in dermal-based tumors. This phenotypic change likely influences the loss of epidermal localization.