Identification of protein-coding and non-coding RNA expression profiles in CD34+ and in stromal cells in refractory anemia with ringed sideroblasts.

BACKGROUND: Myelodysplastic syndromes (MDS) are a group of clonal hematological disorders characterized by ineffective hematopoiesis with morphological evidence of marrow cell dysplasia resulting in peripheral blood cytopenia. Microarray technology has permitted a refined high-throughput mapping of the transcriptional activity in the human genome. Non-coding RNAs (ncRNAs) transcribed from intronic regions of genes are involved in a number of processes related to post-transcriptional control of gene expression, and in the regulation of exon-skipping and intron retention. Characterization of ncRNAs in progenitor cells and stromal cells of MDS patients could be strategic for understanding gene expression regulation in this disease. METHODS: In this study, gene expression profiles of CD34+ cells of 4 patients with MDS of refractory anemia with ringed sideroblasts (RARS) subgroup and stromal cells of 3 patients with MDS-RARS were compared with healthy individuals using 44 k combined intron-exon oligoarrays, which included probes for exons of protein-coding genes, and for non-coding RNAs transcribed from intronic regions in either the sense or antisense strands. Real-time RT-PCR was performed to confirm the expression levels of selected transcripts. RESULTS: In CD34+ cells of MDS-RARS patients, 216 genes were significantly differentially expressed (q-value

[Quantitative evaluation of juxtatrabecular fibrosis in myelodysplastic syndromes]. / Valoración cuantitativa de la fibrosis yuxtatrabecular en los síndromes mielodisplásicos.

PURPOSE: Myelofibrosis is a common, poor-prognosis feature of myelodysplastic syndromes (MDS). The aim of this work was to evaluate quantitatively the extent of the juxtatrabecular fibrosis in primary MDS and in secondary myelodysplasias, along with the presence of immature precursor cells in anomalous position, that is, the displacement of granulopoiesis from the paratrabecular area to central positions. PATIENTS AND METHODS: Twenty-seven bone marrow samples were examined: 9 from primary MDS, 9 from secondary myelodysplasias, and 9 normal. The percentage of myeloblasts and promyelocytes with nucleoli located in the central areas was estimated, in an attempt to correlate such feature with the degree of juxtatrabecular fibrosis. The analysis of data was performed with the Kruskal-Wallis test, values of p < 0.01 being significant. RESULTS: Sectorial juxtatrabecular fibrosis was present in all the myelodysplastic samples, ranging from 6% to 55% of the trabecular surface; the highest values found in the controls were about 3.6% (p < 0.01). Although the juxtatrabecular fibrosis figures are higher in secondary MDS, the difference is not significant with regard to the primary MDS in the number of patients studied here. The count of myeloblasts and promyelocytes with nucleoli present in the MDS was significantly greater than that of the control group. The number of promyelocytes with nucleoli was significantly higher in the primary MDS with respect to the secondary ones, whereas no significant difference was seen between the two types of MDS regarding the myeloblast count. CONCLUSIONS: The increased number of central immature precursor cells in MDS was not directly correlated with the extent of the juxtatrabecular fibrosis. Although the number of cases is small, the fact that the juxtatrabecular fibrosis was higher in the two deceased patients in the series (49% and 56%, respectively) suggests a poor-risk prognosis for such finding.

A new syndrome of refractory sideroblastic anemia with vacuolization of marrow precursors and exocrine pancreatic dysfunction.

In the past decade, we have studied four unrelated children with what we believe is a previously unreported disorder affecting the bone marrow and exocrine pancreas. During infancy these patients had the onset of severe, transfusion-dependent, macrocytic anemia plus a variable degree of neutropenia and thrombocytopenia. Their bone marrows had normal cellularity but were characterized by remarkable vacuolization of erythroid and myeloid precursors, hemosiderosis, and ringed sideroblasts. The vacuoles probably represented manifestations of cellular degeneration and death. In two patients, in vitro bone marrow cultures showed abnormal erythroid and myeloid progenitor cell growth and, in one child, abnormal vacuolated erythroid colonies. Family histories were unrevealing, parents were hematologically normal, and both sexes were involved. There was no evidence of specific nutritional deficiencies or exposure to agents associated with marrow vacuolization. A number of therapeutic interventions produced no effect. One child had clinical malabsorption. This child and one other had extensive pancreatic fibrosis at autopsy. The other two patients had findings indicating exocrine pancreatic dysfunction. Two children had splenic atrophy. This new syndrome, with associated bone marrow and exocrine pancreatic dysfunctions, differs in several respects from the syndrome of pancreatic liposis and neutropenia described by Shwachman et all and Bodian et al, and from other conditions with vacuolization of the marrow or sideroblastosis.