Objective: To explore the inhibitory effect of sera from patients with myelodysplastic syndromes (MDS) on the growth of normal hematopoietic progenitor cells.
Methods: The inhibitory activity to the growth of BFU-E and CFU-GM was analysed by in vitro methylcellulose culture. Hematopoietic cell apoptosis was assayed with a programmed cell death assay kit and flow cytometry.
Results: In the 23 MDS patients studied, a potent inhibitory activity to CFU-GM and BFU-E was demonstrated in 3 and 4 patients, respectively. The inhibitory activity to BFU-E of sera from 3 patients was almost entirely neutralized by anti-TNF alpha McAb. Sera from two MDS patients induced apoptosis of normal hematopoietic progenitor cells.
Conclusion: Inhibitors of hematopoietic progenitor cells are present in sera from some MDS patients. One of the inhibitors might be TNF alpha, which can induce apoptosis, resulting in ineffective hematopoiesis in MDS.