Chronic lymphocytic leukemia and hairy-cell leukemia.

The chronic lymphoid leukemias are a heterogeneous group of disorders with different immunologic, biologic, and clinical features. The most common of these are the B-cell diseases, chronic lymphocytic leukemia and its variants, including prolymphocytic leukemia and hairy cell leukemia. The increased use of immunophenotyping has identified a number of other less common but related disorders. Despite being clonal disorders, the chronic B-cell leukemias exhibit immunologic abnormalities in multiple other lineages, the mechanism for which is not clear. Fludarabine, 2'-deoxycoformycin, and 2-chlorodeoxyadenosine are purine analogues that have advanced the treatment of chronic B-cell leukemias. Fludarabine appears to be the single most effective agent for chronic lymphocytic leukemia, while 2'-deoxycoformycin and 2-chlorodeoxyadenosine are both extremely effective in hairy cell leukemia. A recently completed comparison of alpha-interferon with 2'-deoxycoformycin in hairy cell leukemia may redefine the standard therapy for this disorder. Continued interaction between laboratory and clinical scientists is essential for continued progress in these diseases.