Peripheral blood remission of hairy cell leukemia after transfusion hepatitis.

Hairy cell leukemia is a chronic lymphoproliferative disorder characterized clinically by splenomegaly and cytopenias. Spontaneous remissions are rare and splenectomy is often performed when the blood counts worsen and cause symptoms. Three of our patients with hairy cell leukemia developed recurrent pancytopenia and transfusion-dependent anemia after splenectomy. Each subsequently acquired transfusion hepatitis and in two patients marked hematologic improvement was noted within 2 months. Complete peripheral blood remission occurred within 17 months in all patients although bone marrow infiltration with hairy cells persisted. One patient remains in remission for 12 years; the other two succumbed to infectious illnesses but with normal blood counts. The mechanism by which hepatitis virus induces hematologic recovery in patients with hairy cell leukemia is unknown but may involve augmentation of the interferon system.