DNA content of granulocytes, monocytes, and lymphocytes in the bone marrowsmears of patients with myelodysplastic syndromes

Recently, we have reported a high incidence of DNA hypodiploidy defined as DNA index (DI) in blasts/promyelocytes from 39 patients with myelodysplasti c syndromes (MDS) found to be without a relationship to cytogenetics, In th e present study the DNA content (DI) in granulocytes, monocytes, and lympho cytes measured in the same bone marrow smears from the above patients are r eported. DNA hypodiploidy was found in mature cells, not only in myeloid ce lls (granulocytes and monocytes) but also in lymphocytes, A lower mean DI i n each cell type of patients compared to controls was found. Pairwise compa rison of the mean DI (+/-SE) in 32 patients with normal (n = 22) and abnorm al (n = 10) cytogenetics and controls (n = 8) showed a significantly (P < 0 .01) lower value for each group of patients, respectively, in all cell type s. No difference was found between the two groups of patients. Presence of weak-feulgen stained nuclei (DI < 0.40) in granulocytes and monocytes was m ore pronounced in patients expressing DNA hypodiploid immature cell populat ions, but only occasionally in lymphocytes, suggesting a link to an apoptot ic event and intramedullary cell death. DNA hypodiploidy is shown to be a c ommon feature even in mature cell populations in MDS bone marrows. Clonalit y, by means of DNA content, appears reasonable as regards the granulocytes and monocytes, DNA hypodiploid lymphocytes, on the other hand, might be sma ll blasts (stem cells) or dying cell populations of unknown origin. Am. J, Hematol, 67:112-118, 2001, (C) 2001 Wiley-Liss, Inc.