Abstract
The production of tumor necrosis factor-a (TNFα) was examined in children with acute lymphoblastic leukemia (ALL) in order to assess the peripheral blood monocyte function. Peripheral blood mononuclear cells (PB-MNC) obtained from ALL children were stimulated with OK432 or autologous ALL cells. TNF α in culture supernatant was quantitated by enzyme-linked immunosorbent assay. Sequential study showed that TNFα production following OK432 stimulation reached the peak within 24 hours and declined thereafter. Major producing cells of TNFα in peripheral blood were plastic-adherent cells which were shown to be monocytes morphologically and cytochemically. Most of TNFα was released into culture supernatant, whereas solubilized fraction of OK432-stimulated PB-MNC contained little TNFα. The production of TNFα was well maintained in both ALL cases on chemotherapy and off chemotherapy. There was no significant difference in terms of TNFα production between ALL cases and normal subjects. Instead, inter-patient variation was remarkable in the group of patients on chemotherapy. In mixed cultures with autologous ALL cells, significant TNF-α production was observed in one out of 14 cases, suggesting that the specific anti-tumor immunity might be established.
