Host defence factors and prognosis in hairy cell leukemia

Host defence parameters were characterized in 20 patients with hairy cell leukemia (HCL) and were related to hematological, clinical and prognostic variables. The diagnosis was confirmed by examination on the bone marrow by light and electron microscopy, and by staining for tartrate-resistant acid phosphatase. The major findings were markedly impaired delayed type hypersensitivity to recall antigens (mean skin test diameter in mm, HCL: 4.5, acute myelogenous leukemia: 17.4, normal: 14.8); low lymphocyte blastogenic responses to pokeweed mitogen (patients: 2.33 × 10³ counts per min per culture, normals: 15.1) and concanavalin A (patients: 5.3 × 10³ counts per min, normals: 31.9); low peripheral blood adherent monocytes (patients: 2.7 × 10⁴/ml, normals: 14.8), low serum lysozyme (patients: 1.8 μg/ml, normals: 5.8) and virtually absent antibody-dependent cellular cytotoxicity ADCC to human erythrocytes (patients: 1.6% target cell lysis, normals: 8.7). In vitro addition of allogeneic monocytes restored the pokeweed mitogen and concanavalin A responses in 10 cases. There were significant negative correlations between the extent of bone marrow involvement with leukemia and several host defence parameters including ADCC to chicken erythrocytes (p = 0.002), delayed type hypersensitivity (p = 0.005), ADCC to the human leukemia CEM cell line (p = 0.3) and concanavalin A response (p = 0.03). Variables predicting prognosis included serum lysozyme (p = 0.008), ADCC to CEM (p = 0.009), delayed type hypersensitivity (p = 0.03), adherent monocytes (p = 0.04), concanavalin A response (p = 0.05) and platelet count (p = 0.05). These data indicate the important role of host defence parameters in the course of HCL and indicate the important role of host defence parameters in the course of HCL and indicate pathways for the study of the fundamental nature of the disease and its management.