HLA typing in hairy cell leukemia.

: In HCL patients some cases of familial occurrence of the disease were reported, without an association with a specific haplotype or HLA antigen. In a series of a non familial HCL patients an increase in DR11 frequency was reported. We performed HLA class I and class II antigens in a series of 38 consecutive HCL patients. An increased frequency of B17 (10/38-27%) and DR11 (22/38-57%) antigens compared with the normal Caucasian population was recorded. As clinical characteristics, no significant differences were recognized between DR11 positive and DR11 negative patients. In response to IFN treatment, a complete response (CR) was achieved in 20% of DR11 patients and in 46% of DR11 negative patients. In this study an increase frequency of B17 and DR11 antigens was found; furthermore DR11 positive patients seem to be less responsive to IFN treatment but a larger series of patients will have to be studied in the future in order to establish this observation with more certainty.