Interferon Production and Lymphocyte Transformation in Lymphocytes of Leukemic Patients

The high incidence of viral infections in patients with lymphocytic leukemia is well documented, but the role played by interferon in the pathogenesis of such infections is not known. In this study, we investigated the possibility that gamma (γ)interferon production, induced by phytohemagglutinin (PHA) might be impaired in leukocytes from patients with acute lymphocytic leukemia (ALL). We also compared this response with alpha (α) interferon production, and with PHA-stimulated lymphocyte transformation. We have shown that the γ interferon response of leukocytes from patients, both in relapse and in remission, was markedly lower than in leukocytes from normal donors. However, the α interferon response in leukocytes from the patients was normal. In contrast to the defective γ interferon response to PHA stimulation of cells from patients in remission, lymphocyte transformation by PHA was normal. Lymphocytes from patients in relapse had a delayed response. Our findings suggest (1) that the defective γ interferon response which occurs in cells from patients with ALL, both in relapse and remission, contributes to increased susceptibility to viral infections, (2) that α interferon may not be the optimal type of interferon for treatment of certain viral infections, and (3) that different triggering mechanisms, or different receptors, exist for PHA-induced γ interferon production and for lymphocyte transformation in cells of patients with ALL.