Treatment of hairy-cell leukemia.

AIRY CELL LEUKEMIA (HCL), or leukemic reticuH loendotheliosis, is a chronic lymphoproliferative disease that was first described as a distinct clinicopathologic entity by Bouroncle et a1 in 1958.' It is characterized by mononuclear cells of B-lymphocyte origin in the peripheral blood that have prominent cytoplasmic projections staining with tartrate-resistant acid phosphatase' and by its typical pattern of infiltration in the bone marrow and spleen.' Patients, usually middle-aged men, often present with pancytopenia, severe infections, or splenomegaly. Before the introduction of effective systemic therapy, the median survival was only 53 months3 If the morphologic appearance of HCL does not sufficiently establish it as a curious disorder, its treatment history does. First, in contrast to other hematologic malignancies, splenectomy was shown to almost universally result in amelioration of cytopenias, which is often durable. Subsequently, HCL was the malignant disorder for which the first biologic therapy, a-interferon (a-IFN), was successfully used and eventually approved by the Food and Drug Administration (FDA). More recently the nucleosides have been shown to have dramatic activity in HCL; first, deoxycoformycin treatment resulted in frequent durable complete remissions and subsequently 2-chlorodeoqadenosine has produced high numbers of durable complete remissions with a single infusion of drug. Hence, since the last review of the treatment of HCL here in 1987; dramatic results have been accomplished in the treatment of this rare dis~rder.'.~ Treatment advances, management considerations, and a view of the future will be discussed.