Clone REA533 recognizes the human fetal hemoglobin (HbF) antigen, a form of hemoglobin present during fetal development. The hemoglobin molecule is a tetramer composed of two subunits of α-like globin peptide chains and two subunits of the β-like globin peptides, along with heme moieties necessary for this molecule´s oxygen-carrying capacity. When production of the first enucleated definitive erythrocytes commences from stem and progenitor cells in the fetal liver, the predominant β-like globin molecule produced is γ-globin. The γ-globin chains combine with adult α-globin chains into a stable tetramer forming HbF. Shortly after the time of birth there is a switch from predominant expression of HbF to adult hemoglobin (HbA), which is mediated by a transcriptional switch in definitive erythroid progenitors from γ- to β-globin. The synthesis of HbF is normally reduced to very low levels of less than 0.6% of the total hemoglobin in adults. HbF levels may be increased in adults in a number of inherited and acquired disorders. The clinical significance of these conditions with raised HbF relates to their interaction in disorders such as sickle cell disease and β-thalassemia in which raised levels of HbF can lead to considerable amelioration of disease severity.

Additional information: Clone REA533 displays negligible binding to Fc receptors.