Biologic characteristics of patients with hypocellular myelodysplastic syndromes

Rates of proliferation and apoptosis as well as expression of tumor necrosi s factor alpha (TNF-alpha), transforming growth factor beta (TGF-beta) and the number of macrophages were measured in bone marrow (BM) biopsies of 33 patients who presented with hypocellular (cellularity < 30%) myelodysplasti c syndromes (MDS). Results showed that 2/3 of the patients had high apoptos is, high cytokine levels and large number of macrophages in their biopsies while 1/3 did not. Apoptosis and TNF-alpha levels were directly related (r = 0.583, P = 0.003, n = 24) as was apoptosis and the degree of anemia (P = 0.033, n = 18). A subgroup of patients with abnormalities of chromosomes 5 or 7 had higher platelets (P = 0.026) and higher apoptosis (P = 0.038) when compared with the rest of the group. Eight patients had no evidence of apo ptosis and almost no detectable TNF-alpha in their biopsies. We conclude th at within the hypocellular variant of MDS, then may be two distinct sub-gro ups of patients, one who present with high cytokine-mediated intramedullary apoptosis and the other who may be better characterized as having a stem-c ell failure defect since they showed no evidence of apoptosis. (C) 1999 Els evier Science Ltd. All rights reserved.