Refractory cytopenia of childhood is the most common type of childhood myelodysplastic syndrome. Because the majority of children with refractory cytopenia have a normal karyotype and a hypocellular bone marrow, differentiating refractory cytopenia from the immune-mediated bone marrow failure syndrome (very) severe aplastic anemia can be challenging. Flow cytometric immunophenotyping of bone marrow has been shown to be a valuable diagnostic tool in differentiating myelodysplastic syndrome from non-clonal cytopenias in adults. Here, we performed the first comprehensive flow cytometric analysis of immature myeloid, lymphoid cells and erythroid cells, and granulocytes, monocytes, and lymphoid cells in bone marrow obtained from a large prospective cohort of 81 children with refractory cytopenia. Children with refractory cyotopenia had a strongly reduced myeloid compartment, but not as severe as children with aplastic anemia. Furthermore, the number of flow cytometric abnormalities was significantly higher in children with refractory cytopenia than in healthy controls and in children with aplastic anemia, but lower than in advanced myelodysplastic syndrome. We conclude that flow cytometric immunophenotyping could be a relevant addition to histopathology in the diagnosis of refractory cytopenia of childhood. (The multi-center studies EWOG-MDS RC06 and EWOG-MDS 2006 are registered at clinicaltrials.gov identifiers 00499070 and 00662090, respectively).

• MeSH
• aplastická anemie diagnóza   imunologie   patologie   MeSH
• CD antigeny imunologie   MeSH
• diferenciální diagnóza MeSH
• dítě MeSH
• erytroidní buňky imunologie   patologie   MeSH
• granulocyty imunologie   patologie   MeSH
• imunofenotypizace * MeSH
• kojenec MeSH
• kostní dřeň imunologie   patologie   MeSH
• lidé MeSH
• lymfocyty imunologie   patologie   MeSH
• mladiství MeSH
• monocyty imunologie   patologie   MeSH
• myelodysplastické syndromy diagnóza   imunologie   patologie   MeSH
• pancytopenie diagnóza   imunologie   patologie   MeSH
• předškolní dítě MeSH
• průtoková cytometrie MeSH
• stupeň závažnosti nemoci MeSH
• Check Tag
• dítě MeSH
• kojenec MeSH
• lidé MeSH
• mladiství MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• klinické zkoušky MeSH
• multicentrická studie MeSH
• práce podpořená grantem MeSH

Erythropoiesis is a multistep process regulated at the molecular level by intrinsic and extrinsic factors including microRNAs (miRNAs). We previously identified aberrant expression of miR-451 and miR-150 in polycythemia vera (PV) erythroid differentiating cells. To address the functional relevance of these miRNAs in erythroid differentiation, we employed synthetic mimics and inhibitors of miR-451 and miR-150 in erythroid differentiating K562 cells. We observed that miR-451 up-regulation and miR-150 down-regulation are associated with progression of erythroid maturation in K562 cells. Further, enforced expression of miR-451 promoted erythroid differentiation. Inhibition of miR-150 reduced hemoglobinization of K562 cells. Microarray data suggested potential targets regulated by miR-451: UBE2H, ARPP-19; and by miR-150: MS4A3, AGA, PTPRR. Our results demonstrate that miR-451 is involved in the regulation of erythroid differentiation and functions as an enhancer of differentiation. These data support the concept that aberrant expression of miRNAs may contribute to abnormal erythropoiesis such as that of PV.

• MeSH
• akutní erytroblastická leukemie genetika   patologie   MeSH
• buněčná diferenciace účinky léků   genetika   MeSH
• buňky K562 MeSH
• erytroidní buňky účinky léků   patologie   MeSH
• erytropoéza účinky léků   genetika   MeSH
• hemin farmakologie   MeSH
• lidé MeSH
• mikro RNA genetika   fyziologie   MeSH
• nádorové buněčné linie MeSH
• regulace genové exprese u leukemie účinky léků   MeSH
• sekvenční analýza hybridizací s uspořádaným souborem oligonukleotidů MeSH
• stanovení celkové genové exprese MeSH
• transfekce MeSH
• upregulace účinky léků   fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Polycythemia vera (PV) is an acquired myeloproliferative clonal disorder, characterized by augmented erythropoiesis. To better define PV pathogenesis, we performed an in vitro erythroid expansion from peripheral blood mononuclear cells of controls and PV patients and evaluated the cells for proliferation, apoptosis, erythroid differentiation, and morphology at the defined time points. PV erythroid progenitors exhibited increased proliferation at days 9-14 and accelerated maturation at days 7-14, with a larger S-phase population (40%) than controls (20%) at day 11; however, the proportion of apoptotic cells was comparable to controls. Previously, we have identified PV-specific dysregulation of several microRNAs (i.e. miR-150, 451, 222, 155, 378). We had analyzed expression profiles of selected target genes of these microRNAs based on in silico prediction and their known function pertinent to the observed PV-specific erythropoiesis differences. p27, cMYB and EPOR showed differential expression in PV erythroid progenitors at the specific stages of erythroid differentiation. In this study, we identified accelerated maturation and hyper-proliferation at early stages of PV erythropoiesis. We speculate that aberrant expression of p27, c-MYB, and EPOR may contribute to these abnormal features in PV erythropoiesis.

• MeSH
• buněčný cyklus MeSH
• erytroidní buňky cytologie   patologie   MeSH
• erytroidní prekurzorové buňky cytologie   patologie   MeSH
• erytropoéza MeSH
• geny myb genetika   MeSH
• inhibitor p27 cyklin-dependentní kinasy genetika   MeSH
• kultivované buňky MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• polycythaemia vera genetika   patologie   MeSH
• receptory erythropoetinu genetika   MeSH
• regulace genové exprese MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH