Tumor necrosis factor-β in the serum of adult T-cell leukemia with hypercalcemia

Abstract

Serum tumor necrosis factor-β (TNF-β) from patients with adult T-cell leukemia (ATL) was studied by a sandwich enzyme-linked immunosorbent assay (ELISA) developed in our laboratory using biotinylated monoclonal anti-TNF-β and recombinant TNF-β. Seven of eight patients with hypercalcemia showed elevation of serum TNF-β. On the other hand, TNF-β could not be detected by the ELISA in 28 patients without hypercalcemia. The lower detection limit in this assay was 100 pg/mL, corresponding to 500 pg/mL by the conventional method. In two patients serum TNF-β level decreased after treatment in association with the level of serum calcium. Furthermore, immuno-staining using antiTNF-β and avidin-biotin complex showed the presence of cytoplasmic TNF-β in not only human T-cell leukemia virus type I infected cell lines, but also freshly isolated cells from ATL patients with hypercalcemia. The actual biologic activity of TNF-β in serum was confirmed by a conventional bioassay in a patient with hypercalcemia, and its cytotoxic activity was inhibited by the addition of anti-TNF-β antibody in the assay. These results suggested that serum TNF-β might be one of the factors contributing to the hypercalcemia, at least in patients with ATL. © 1991 by The American Society of Hematology.