α-Haemoglobin stabilising protein expression is influenced by mean cell haemoglobin and HbF levels in HbE/ß-thalassaemia individuals.

ABSTRACT

The alpha haemoglobin stabilising protein (AHSP) acts as a molecular chaperone for α-globin by stabilising nascent α-globin before transferring it to waiting free ß-globin chains. Binding of AHSP to α-globin renders α-globin chemically inert whereby preventing it from precipitating and forming reactive oxygen species byproducts. The AHSP has been actively studied in the recent years, particularly in its relation to ß-thalassaemia. Studies have shown that AHSP is a modifier in ß-thalassaemia mice models. However, this relationship is less established in humans. Studies by some groups showed no correlation between the AHSP haplotypes and the severity of ß-thalassaemia, whereas others have shown that certain AHSP haplotype could modify the phenotype of ß-thalassaemia intermedia patients. We investigated the expression of AHSP in relation to selected demographic data, full blood count, HPLC results, HbE/ß-thalassaemia genotype, Xmn-1 Gγ polymorphism, α-globin, ß-globin and γ-globin expression. We found that AHSP expression was significantly correlated to mean cell haemoglobin level, HbF %, α-globin, ß-globin and excess α-globin expression. We concluded that AHSP could be a secondary compensatory mechanism in red blood cells to counterbalance the excess α-globin chains in HbE/ß-thalassaemia individuals.