LEUKEMIA INHIBITORY FACTOR CONCENTRATIONS IN THE BONE-MARROW PLASMA OF HEALTHY-SUBJECTS AND PATIENTS WITH HEMATOLOGIC MALIGNANCIES

Several cytokines may play a role in the pathogenesis of varioushemato poietic malignancies. As cytokines work locally, we have investigated leukemia inhibitory factor (LIF) concentrations in the bone marrow pla sma of healthy subjects and patients with hematopoietic malignancies b y using a specific enzyme-linked immunosorbent assay. LIF levels in pa tient's samples were significantly higher in bone marrow plasmas (330. 3 +/- 43.6 pg/ml; n = 29) than LIF levels in blood plasmas (178.9 +/- 16.8 pg/ml; n = 43) (p = 0.0006, Mann-Whitney U-test). Marrow stromal cells which constitutively produce LIF and enhance their synthesis in response to LPS and PMA might be the cell source of the bone marrow-de rived LIF. No statistical difference was documented between marrow pla sma LIF concentrations of 24 patients with hematological malignancies and healthy controls. At the present time, the role of LIF in the huma n marrow cytokine network requires further evaluation.