Serum concentrations of soluble transferrin receptor among paediatric patients with transfusion-dependant β-thalassaemia/haemoglobin E

Abstract

In Thailand, anaemia in pregnancy may be addition to the repertoire of indices of iron status. In fact, sTfR concentration has been the result of iron deŽ ciency but is also often caused by genetic haemoglobin (Hb) disshown to be a more sensitive and less variable index of iron status than the more orders, particularly b-thalassaemia/Hb E (Flatz et al., 1965; Fucharoen and Winichagoon, conventional measurements of serum iron, serum transferrin or total iron-binding 1997). Such genetic abnormalities cause many systemic eVects. The unusual fragility capacity (Ahluwalia et al., 1993; Cooper and Zlotkin, 1996; Suominen et al., 1998). of the erythrocytes in those aVected leads to chronic haemolytic anaemia, normal daily The results of only a few systemic studieson sTfR concentrations in b-thalassaemia/Hb E activities may be limited, and jaundice, hepato–splenomegaly, osteoporosis and facial patients have been published and none is speciŽ c to paediatric cases. The aim of the abnormalities are common. Presently about 5 million people in present study was to compare sTfR concentrations in children with b-thalassaemia/Hb E Thailand suVer from Hb abnormalities and about 10,200 of these (representing about or b-thalassaemia major with those in healthy, non-anaemic controls of similar ages. 1.2% of all of those born each year) are neonates. In Thailand, as elsewhere, blood The 45 patients, aged 4–10 years, were all attending the Divisions of Pediatrics transfusions are given to those aVected to try to keep their Hb concentrations near and Laboratory Medicine at the King Chulalongkorn Memorial Hospital (KCMH) normal. Unfortunately there are often shortages of banked blood, and variation in the in Bangkok. Any child with a concomitant acute manifestation, iron deŽ ciency, chronic way haematocrits are routinely monitored causes unreliability in the long-term follow-up in ammatory condition or dietary restriction was excluded. Most (40) of the cases had of the patients. Suominen et al. (1998) recently suggested transfusion-dependant b-thalassaemia/Hb E [with a mean (s.d.) pre-transfusion conthat concentrations of transferrin receptor (TfR), a glycoprotein mediating the entry of centration of 7.3 (2.1) g Hb/dl)]. The other Ž ve cases had transfusion-dependant ferric transferrin from the extracellular compartment into cells, could be used to monib-thalassaemia major [7.2 (2.4) g Hb/dl]. Thirty children who were of similar ages to tor erythropoiesis. As up-regulation of the expression of cellular TfR occurs as a result the cases, appeared healthy and non-anaemic and were found to have normal erythrocytic of an inadequate tissue supply of iron or of an increased cellular demand for iron, parameters when investigated using an automated haematology analyser (Technicon elevations in the serum concentrations of the soluble form of TfR (sTfR) can be detected H*3; Bayer Diagnostics, Newbury, U.K.) served as controls. The controls were studied in many anaemic disorders. In clinical settings, sTfR concentrations while attending the KCMH for routine health checks, well-baby clinics or vaccinations. have been widely measured as an attractive