A number of infections with parasitic agents such as Plasmodium, Schistosoma, Leishmania or hookworms result in anemia [22] and [24]. In the case of intestinal infections, this anemia is believed to be caused primarily by intestinal hemorrhage, reduced iron absorption or decreased bioavailability of iron [29]. Inflammatory responses to the infections including the secretion of proinflammatory cytokines and/or the resultant upregulation of hepcidin additionally appear to inhibit erythropoiesis, as in the anemia of chronic disease [4] and [27]. In the case of malaria and leishmaniasis, evidence exists that parasitic products may also directly

impede erythroid proliferation and/or differentiation [13] and [33]. On the other hand, erythropoiesis can become dysregulated in certain myeloproliferative disorders leading Ku0059436 to uncontrolled proliferation of erythroid cells. In the erythroleukemia polycythemia vera for example a mutation in the Janus tyrosine kinase JAK2 renders erythroid proliferation independent of erythropoietin and causes excessive red cell production [20] and [23]. In vitro methods for the generation of erythroid cells from hematopoietic stem cells derived from various

sources have LY2835219 been established and shown to yield both high proliferation of erythroid cells and produce functional, mature, enucleated reticulocytes or erythrocytes, thus faithfully recapitulating Suplatast tosilate the in vivo process [3],

[11] and [12]. In general, the differentiation process of erythroid progenitor cells and their maturation is characterized by the acquisition of specific erythroid features including particular surface markers, an exit from the cell cycle and the accumulation of large amounts of hemoglobin that is responsible for the cells’ ability to bind oxygen [35] and [39]. A tetramer of 4 globin chains with a central heme molecule, hemoglobin shows a spectrophotometric absorbance peak between 400 and 420 nm, which has been exploited for the quantification of hemoglobin in solution by Harboe and others [5], [14] and [15]. As this characteristic can be used for hemoglobin quantification not only in solution but also when cell-bound, we have developed a spectrophotometric assay for assessing erythroid proliferation based on absorbance at 405 nm. All chemicals were obtained from Sigma–Aldrich (Arklow, Ireland) unless stated otherwise. Mononuclear cells (MNC) were isolated from peripheral blood buffy coats obtained from the Irish Blood Transfusion Services (Dublin, Ireland) using density gradient centrifugation with histopaque-1077. CD34+ cells were isolated from mononuclear cells via immuno-magnetic separation using anti-CD34 magnetic beads according to the manufacturer’s instructions (Miltenyi Biotec, Bisley, UK). Cultures were initiated from frozen or freshly isolated mononuclear cells or CD34+ cells.