Immunoregulatory abnormalities in myelodysplastic disorders

Abstract

Immunoregulation was assessed in a group of patients with myelodysplasia (MDS) by flow cytometric analysis of peripheral blood lymphocyte subsets and in vitro studies of mitogen-stimulated T-lymphocyte blastogenesis. Mitogenesis was significantly depressed in MDS patients compared to controls (p < .001) and a similar defect was found in a small group of patients with untreated acute nonlymphocytic leukemia (ANLL) (p < .005). The impaired mitogenic response ability of T-cells in these patients did not appear to be the result of alteration in lymphocyte subpopulation ratios. The observed defect might result from defective cooperation between Tlymphocytes and abnormal myeloid elements. Alternatively, the lymphocytes themselves could be derived from the abnormal clone and thus be functionally abnormal.