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Type: Artigo de periódico
Title: Maturation-associated immunophenotypic abnormalities in bone marrow B-lymphocytes in myelodysplastic syndromes
Author: Ribeiro, E
Sudon, SM
de Santiago, M
Lima, CSP
Metze, K
Giralt, M
Saad, STO
de Matos, AO
Lorand-Metze, I
Abstract: Recent studies concerning the pathophysiology of myelodysplastic syndromes (MDS) have shown evidences for the existence of complex interactions between hematopoietic stem cells and the bone marrow (BM) microenvironment. We analyzed the B-lymphocyte maturation in BM of patients with MDS. For this purpose, 41 newly-diagnosed patients were analyzed. Enumeration and characterization of CD34+ and CD34- B-cell precursors and mature B-lymphocytes was performed using multiparameter flow cytometry. BM from eight transplant donors and six orthopedic surgery patients were used as controls. CD34+/CD45(lo) B-cells were found in 17/22 patients with RA/RARS and in 5/13 with RAEB. In patients with RAEB-t and CMML no CD34+ B-cell precursors could be detected. A positive correlation was found between CD34+ and CD34- B-cell precursors (r = 0.52). CD34+ B-cell precursors presented an inverse correlation with BM percentage of blasts and peripheral leukocytes and a positive one with hemoglobin. Asynchronous antigen expression (CD19+/CD79a- cells) was found in 7/11 cases of RA/RARS and 6/18 cases of RAEB in which this phenotype was examined. Abnormal patterns of expression for at least one antigen was found in 91% of RA/RARS cases and in 74% of RAEB. Underexpression of TdT and CD79a were the most frequent abnormalities. Our results present evidences of an abnormal B-cell maturation in MDS. This may be an evidence that B-lymphocytes are derived of the abnormal clone. But it may also be the consequence of influences of abnormalities of BM microenvironment leading to an impaired commitment and maturation of the B-cell line in MDS. Studies performed with purified well-characterized B-cells may further elucidate these abnormalities. (c) 2005 Elsevier Ltd. All rights reserved.
Subject: myelodysplastic syndromes
bone marrow
B-cell maturation
flow cytometry
Country: Inglaterra
Editor: Pergamon-elsevier Science Ltd
Rights: fechado
Identifier DOI: 10.1016/j.leukres.2005.05.019
Date Issue: 2006
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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