Markers of ineffective erythropoiesis in non-transfusion dependent β-thalassaemia

Non-transfused β-thalassaemia patients develop complications related to unsuppressed ineffective erythropoiesis (IE). Serum markers of IE would be useful for risk stratification and monitoring treatment. We studied β- thalassaemia trait (β-TT) and non-transfusion-dependent β- thalassaemia (β-NTDT) patients. Serum erythropoietin (EPO) and soluble transferrin receptor (sTfR) were correlated against markers of clinical severity (haemoglobin, LDH, retics, bilirubin, spleen size) and iron overload (ferritin, hepcidin, and MRI-T2* in NTDT patients). Eleven β-NTDT and nine β-TT subjects were studied. β- NTDT patients had significantly higher markers of haemolysis and iron overload. In β-NTDT, liver iron ranged from mild to severe, but no cardiac loading was seen. EPO and sTfR were higher in patients with β-NTDT than β-TT, and correlated significantly with each other (ρ=0.630, p=0.003). Both markers were negatively correlated with haemoglobin (sTfR ρ=-0.540, p=0.014; EPO ρ=-0.807, p<0.001, and positively correlated with spleen size (sTfR ρ=0.783, p<0.001; EPO ρ=0.654, p=0.002) and markers of iron overload. There was a strong correlation between ferritin and hepcidin (ρ=0.720, p<0.001), and a relatively lower increment of hepcidin for the degree of iron overload in β- NTDT compared to β-TT. EPO and sTfR appear to be reliable markers of erythropoiesis in non-transfused β-thalassaemia and correlate well with markers of disease severity. Their role in managing patients, predicting complications, and monitoring response to treatments aimed at reducing IE should be explored.