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Kimura A.,Laboratory of Genetics and Physiology | Martin C.,Laboratory of Genetics and Physiology | Robinson G.W.,Laboratory of Genetics and Physiology | Simone J.M.,Flow Cytometry Section | And 4 more authors.
Journal of Biological Chemistry | Year: 2010

Cytokines control the biology of hematopoietic stem cells (HSCs) and progenitor cells in part through the transcription factors STAT5A/B. To investigate the target genes of STAT5A/B activated by cytokines in HSCs and progenitors, we performed microarray analyses using Lineage- Sca-1+ c-Kit+ (KSL) cells in the presence and absence of STAT5A/B. Stimulation with a mixture containing IL-3, IL-6, stem cell factor, thrombopoietin, and Flt3 ligand induced Ccn3/Nov mRNA over 100-fold in WT (control) but not Stat5a/b-null KSL cells. CCN3/NOV is a positive regulator of human HSC self-renewal and development of committed blood cells. Without stimulation, the Ccn3/Nov signal level was low in control KSL cells similar to Stat5a/b-null KSL cells. To determine which cytokine activates the Ccn3/Nov gene, we analyzed Lineage- c-Kit+ (KL) and 32D cells using quantitative PCR and ChIP assays. Although stimulation with a mixture lacking IL-3 prevented the induction of Ccn3/Nov in control KL cells, IL-3 alone could induce Ccn3/Nov mRNA in control KL and 32D cells. ChIP assays using 32D cells revealed IL-3-induced binding of STAT5A/B to a γ-interferon-activated sequences site in the Ccn3/Nov gene promoter. This is the first report that Ccn3/Nov is directly induced by cytokines through STAT5A/B.

Subira D.,Flow Cytometry Section | Uriel M.,Clinica Quiron | Serrano C.,Unilabs Laboratory | Castanon S.,Flow Cytometry Section | And 4 more authors.
Cytometry Part B - Clinical Cytometry | Year: 2011

Background: Fetal erythrocytes cross the placenta during gestation, but invasive prenatal procedures might develop into fetomaternal hemorrhage (FMH). We examine whether flow cytometry immunophenotyping might be useful for measuring the volume of FMH after such procedures. Methods: Fetal erythrocytes (%) were determined in 153 pregnant women after amniocentesis (129) and chorionic villous sampling (24) using a monoclonal antibody against fetal hemoglobin. Fetal erythrocytes were identified for their high expression of fetal hemoglobin (HbF ++). Blood samples from two control groups, 53 healthy males and 21 pregnant women not submitted to invasive tests, were used to establish normal values of circulating HbF ++ erythrocytes in adults. Results: The highest percentage of HbF ++ erythrocytes in the control groups was 0.015%. The rate of HbF ++ erythrocytes in samples after invasive tests ranged between <0.01% and 0.15%. Seventy three women (47%) had ≤0.015% HbF ++ erythrocytes, and this rate was higher in 80. Nine women presented >1 ml of FMH (volume of packed cells corresponding to 0.054-0.15% HbF ++ erythrocytes), but only two had sonographic evidence of bleeding. Conclusions: Most women in our series had a very low volume of FMH after the invasive tests. Acute bleeding should be thoroughly investigated in women with either more than 1 ml of packed cells or more than 0.05% of HbF ++ erythrocytes. Intermediate values between >0.015% and <0.05%, should be carefully considered depending on the week of gestation. Data obtained before 15 weeks might reflect previous cell trafficking between fetus and mother instead of acute hemorrhage. © 2010 International Clinical Cytometry Society.

Pulini S.,Spirito Santo Hospital | Marando L.,University of Naples Federico II | Natale A.,Spirito Santo Hospital | Pascariello C.,University of Naples Federico II | And 4 more authors.
Acta Haematologica | Year: 2011

The clinical and biological spectrum of paroxysmal nocturnal hemoglobinuria (PNH) is variable, ranging from classical hemolytic forms to PNH associated with aplastic anemia or other bone marrow (BM) failure syndromes. We report a previously undescribed case of PNH occurring after autologous stem cell transplantation (ASCT) in a patient affected by relapsing non-Hodgkin's lymphoma. The intensive chemotherapy and the ASCT resulted in a contraction of the effective hematopoietic stem cell (HSC) pool and a derangement of the immune system. The delayed engraftment and the BM hypoplasia represented a favorable environment for the expansion of the pathological clone. This case is paradigmatic even for the unexpected trend of the PNH clone during treatment with the terminal complement inhibitor eculizumab; in fact, the clone reduced until undergoing unexpected extinction, i.e. the recovery of normal hematopoiesis. Eculizumab seems not to play a direct role in HSC kinetics; the clinical remission probably occurred because the environmental conditions that led to the expansion of the PNH clone were transient and disappeared. Copyright © 2011 S. Karger AG, Basel.

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