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 βthalassaemia trait (β-TT) and non-transfusion-dependent βthalassaemia (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. βNTDT 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 βNTDT 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.

Siriraj I Gγ(Aγδβ)0 -thalassaemia causing severe thalassaemia intermedia in compound heterozygous state with IVS1-1(G→T) mutation

@#The Siriraj I Gγ(Aγδβ)0 -thalassaemia is a novel mutation involving a 118kb deletion of the β-globin gene cluster. It was first reported in 2012 in two unrelated families from the southern part of Thailand. The carriers in the heterozygous state are clinically asymptomatic. Nonetheless, its complex interaction with other β-thalassaemia could give rise to different clinical phenotypes, ranging from mild thalassaemia intermedia to thalassaemia major. We report here a case of a six-year-old Malay boy, presented with pallor, growth failure and hepatosplenomegaly. His haemoglobin at presentation was 9.2g/dL with a mean cell haemoglobin of 22.6pg and a mean cell volume of 69.9fl. His peripheral blood smear showed features of thalassaemia intermedia. Haemoglobin (Hb) analysis revealed markedly raised Hb F (83%), normal HbA2 levels and absent HbA. Deoxyribonucleic acid (DNA) analysis showed compound heterozygous IVS1-1 (G→T) β-globin gene mutation and Siriraj I Gγ(Aγδβ)0 -deletion (genotype βIVS1-1/ β Siriraj I deletion). Both his father and elder sister are carriers of Siriraj I Gγ(Aγδβ)0 -thalassaemia while his mother carries IVS1-1 (G→T) gene mutation. Clinically, the patient is transfusion dependent on six weekly regime. To the best of our knowledge, this is the first reported case in Malaysia involving unique Siriraj I Gγ(Aγδβ)0 -thalassaemia and IVS1-1 (G→T) in a compound heterozygous state. In summary, detection of Siriraj I Gγ(Aγδβ)0 -thalassaemia is essential as this deletion can lead to severe disease upon interaction with a β-thalassemia point mutation as demonstrated in our case. The establishment of effective carrier screening and genetic counselling is important to prevent its adverse consequences.

Serum Soluble Transferrin Receptor Concentration as a Biomarker of Erythropoietic Activity: Surrogate Marker of Adequate Transfusion in Adult Beta-Thalassaemia Intermedia Patients

Management of Beta (β)-thalassaemia intermedia in contrast to β-thalassaemia major patients has no clear guidelines as to indicators of adequate transfusion. Regular blood transfusion suppresses bone marrow erythropoietic activity. Serum soluble transferrin receptor (sTfR) concentration is a marker for erythropoietic activity, with increased sTfR being associated with functional iron defi ciency and increased erythropoietic activity. This study aimed to determine the use of sTfR as an indicator of adequate transfusion in adult β-thalassaemia intermedia patients. A cross-sectional study was conducted at Hospital Ampang, Malaysia, for six months. Patient group included six β-thalassaemia intermedia and 34 HbE-β-thalassaemia transfused patients. None of the patients were on regular monthly blood transfusions as in β-thalassaemia major. The control group comprised of 16 healthy subjects with normal haematological parameters. Haemoglobin (Hb) analysis, sTfR and ferritin assays were performed. Hb and HbA percentages (%) were found to be signifi cantly lower in patients compared to the controls, while HbE%, HbF%, sTfR and ferritin were signifi cantly higher in patients. An inverse relationship was found in the controls between HbF% with Hb (r = -0.515, p < 0.05) and HbA% (r = -0.534, p < 0.05). In patients, sTfR showed an inverse relationship with HbA% (r = -0.618, p = 0.000) and a positive correlation with HbE% (r = 0.418, p = 0.007) and HbF% (r = 0.469, p = 0.002). Multivariate analysis showed that HbA% (r = 2.875, p = 0.048), HbE% (r = 2.872, p = 0.020) and HbF% (r = 2.436, p = 0.013) best predicted sTfR independently in patients. Thus, sTfR is a useful marker for erythropoiesis. The elevated sTfR in these patients indicate that the transfusion regimen used was inadequate to suppress ineffective erythropoiesis. Hb levels may not be the best target for monitoring transfusion treatment in β-thalassaemia intermedia patients, but the use of sTfR is helpful in individualising transfusion regimens.