Defective mononuclear phagocyte function in patients with myelomonocytic leukemia and in some patients with lymphoma.

Mononuclear phagocytes from 8 of 10 patients with myelomonocytic leukemia and 2 of 9 patients with lymphoma phagocytized several species of bacteria but did not inhibit intracellular bacterial replication normally. Intracellular organisms were protected from the lethal effects of antibiotics in the medium. This defect of microbicidal function of malignant monocytes may explain in part the frequency of infection and the mechanism of antibiotic-resistant infection in some patients with malignant myeloproliferative and lymphoproliferative diseases.