Association of HLA-DR5 with mycosis fungoides.

Mycosis fungoides (MF) and Sézary syndrome (SS) are uncommon neoplasms of the lymphoreticular system with distinct clinical, histologic, and immunologic features. Based on the thymus-derived nature of the neoplastic cells, MF and SS are both classified as cutaneous T-cell lymphoma. While substantially greater understanding of MF and SS has been made possible, the exact mechanism for the initiation of either disease is still unknown. The possible involvement of environmental factors as well as viral etiology, i.e., retroviruses, has been suggested. In order to investigate the possible role of HLA-associated variations in genetic susceptibility, 74 patients with histologically documented MF were typed for HLA-A, -B, and -C antigens. Half of these patients were also typed for HLA-DR antigens. An increase in DR5 was the only statistically significant deviation in HLA antigen frequencies in these patients (53% in MF as compared with 20% in controls). An increased frequency of HLA-DR5 has also been associated with scleroderma and juvenile rheumatoid arthritis both of which have immunologic alterations. Also HLA-DR5 has been associated with renal cell carcinoma and Kaposi's sarcoma. The association of MF with DR5 suggests that some individuals with the DR5 antigen may be at higher risk for virally initiated and/or neoplastic diseases possibly through an HLA-linked defect in the immune system.