ALPHA-THALASSEMIA IS ASSOCIATED WITH INCREASED SOLUBLE TRANSFERRIN RECEPTOR LEVELS

Although alpha(+) thalassaemia is the commonest haemoglobinopathy in t he world, it is not known if it is associated with significant ineffec tive erythropoiesis, a fact of importance in interpreting its complex interaction with malaria, To study this problem, we have measured the concentrations of soluble transferrin receptor (sTfR) and ferritin in 181 children from Vanuatu with heterozygous (68) and homozygous (46) a lpha(+) thalassaemia, and normal controls (67). sTfR concentrations we re significantly higher in both homozygotes (mean 3.1 mg/l, range 2.8- 3.4) and heterozygotes (2.86 mg/l, 2.6-3.2) compared to the normal con trols (2.48 mg/l, 2.3-2.7), suggesting that although globin chain imba lance is minimal, there is ineffective erythropoiesis in both these co nditions. Age was also shown to significantly affect sTfR, with peak l evels occurring in the 5-9 years age group. Ferritin concentrations sh owed a similar trend, being higher in the thalassaemic groups. althoug h this did not reach statistical significance. No individuals had low ferritin concentrations, although two had significantly elevated sTfR levels. These observations suggest that the alpha(+) thalassaemia phen otype includes an expansion of the erythron, and may suggest possible mechanisms for the increased susceptibility in babies with a thalassae mia to both P. falciparum and P. vivax malaria.