Hairy cell leukemia: Clinical effects of the methanol extraction residue (MER) of BCG, lithium carbonate and mononuclear cell-enriched leukocyte transfusions

The effect of MER, lithium carbonate or mononuclear cell-enriched leukocyte transfusions was investigated in eleven patients with hairy cell leukemia. These therapeutic modalities were intended to enhance hematopoiesis and restore the immune abnormalities which occur in these patients. Treatment programs consisted of either MER (0.1-0.5 mg/m² i.v. weekly) or one to two series of three consecutive mononuclear cell transfusions (MNCT), each transfusion containing a mean of 10.6 ± 1.5 × 10⁹ cells/mm³ (8.4 ± 2.9 × 10⁹ lymphocytes and 1.96 ± 1.5 × 10⁹ monocytes) or both. A number of patients were given lithium carbonate followed by MER and then lithium with MER on alternate weeks. A complete hematologic response (CHR) was defined as: hemoglobin above 12 g/dl; neutrophil count > 1500 cells/mm³ and platelet count of > 100,000 mm³. A partial hemotological response (PHR) was defined as recovery of at least two of these parameters. Two CHR and two PHR were seen in patients who received MNCT. Three additional patients who received MER or lithium-MER showed improvement in one hematological parameter. The incidence of infection was significantly lower in the patients who responded to treatment than in those who did not (p < 0.04). Biological stimulation with allogenic cells improved bone marrow failure in patients with HCL. It is expected that hematological recovery and a decrease in the incidence of infections will result in prolonged survival for patients. The contribution of immunoadjuvants or pharmacological agents such as lithium to this therapeutic approach in HCL or other leukemic states where chemotherapy is not desirable requires further investigation.