Primary cutaneous CD8+ and CD56+ T-cell lymphomas express HLA-G and killer-cell inhibitory ligand, ILT2

Primary cutaneous lymphomas constitute a spectrum of diseases characterized by a clonal accumulation of lymphocytes in the skin. Cutaneous T-cell lymphomas of the cytotoxic phenotype, including CD8+ and CD56+ lymphomas, are rare entities that have only been recently recognized and characterized. These lymphomas often show an aggressive clinical course. We investigated the expression of human leukocyte antigen G (HLA-G) and interleukin 10 (IL-10) in conjunction with expression of HLA-G killer-cell inhibitory receptor ligand immunoglobulin-like transcript 2 (ILT2) in 3 CD56+CD4+ and 4 CD8+ cutaneous T-cell lymphomas. HLA-G expression was detected in 2 of 3 lymphomas of the CD56+CD4+ type and in all lymphomas of CD8+ type. It is of note that CD56+CD4+ lymphomas displayed stronger HLA-G reactivity. The expression of IL-10 matched the expression of HLA-G. Together with the expression of IL-10, HLA-G might be one of the factors accounting for the evasion of immunosurveillance, thus contributing to aggressive phenotype of these lymphoma entities.