Elevated serum transferrin receptor levels in common types of thalassemia heterozygotes in Southeast Asia: a correlation with genotypes and red cell indices.

Background: Serum transferrin receptor (sTfR) measurement is a helpful test for diagnosis of iron deficiency. Increased values are detectable in thalassemia syndromes due to increased erythropoiesis. However, sTfR has never been studied in hemoglobin E (HbE) carriers and their interactions with alpha-thalassemia heterozygotes that are common in Southeast Asia.

Methods: We determined sTfR concentrations using a particle enhanced immunoturbidimetric assay in 113 early pregnancies without iron deficiency.

Results: Patients were genotypically classified into 6 groups: 23 normal (mean sTfR+/-SD mg/l, 0.94+/-0.22), 14 alpha(+)-thalassemia heterozygotes (1.06+/-0.45), 21 alpha(0)-thalassemia heterozygotes (1.31+/-0.35), 30 HbE heterozygotes (1.11+/-0.26), 13 HbE heterozygotes with alpha(+)-thalassemia heterozygotes (1.09+/-0.32), and 12 HbE heterozygotes with alpha(0)-thalassemia heterozygotes (1.16+/-0.27). sTfR concentrations in all thalassemic groups were higher than controls, and significantly correlated with high red cell count, low MCV and MCH (p<0.001). When alpha(0)- or alpha(+)-thalassemia combined with HbE, sTfR concentrations were declined compared with alpha(0)-thalassemia or hemoglobin E, respectively, suggesting more balances in alpha- and beta-globin chain production.

Conclusions: Mildly increased erythropoiesis represented by increased sTfR concentrations in alpha-thalassemia and HbE heterozygotes and illustrated alpha- and beta-thalassemic gene interaction. These findings warrant further investigations on sTfR in diagnosis of iron deficiency in thalassemia carriers.