Background/Case Studies: Blood group serology may be inadequate for patients receiving transfusions. Red cell genotyping in Turkey 2013 demonstrated 51% of transfused patients with a discrepancy between phenotype and genotype. However, red cell genotyping has not become a routine diagnostic method in Turkey. We aim to compare red cell genotyping with serological methods and evaluate possible clinical consequences in children with β-thalassaemia major.
Study
Design/Methods: All patients with β-thalassaemia major followed at the main outpatient clinic in Ankara between January and September 2024 were studied. Many children have arrived from Syria since 2011. Transfusion data and EDTA-anticoagulated peripheral whole blood were collected. HEA BeadChip DNA array was used.
Results/Findings: We collated the demographics of 51 consecutive patients. No parameter differed between the 2 nationalities. Patient age was not associated with liver function tests, ferritin, echocardiography or MRI findings.
We analysed 6 antigens of the Rh and Kell systems and found 25 patients (49%) with at least 1 phenotype/genotype discrepancy (Table 1). Mixed-field reaction in serological typing occurred in 6 and alloantibodies in 3 patients (5.8%). Transfusions, weight or height percentiles, ferritin, liver function tests, echocardiography and MRI did not differ between patients with or without phenotype/genotype discrepancy.
Cardiac iron overload occurred in 3 Turkish and 2 Syrian patients and was not associated with phenotype/genotype discrepancy (p=0.63). However, hepatic iron overload, assessed by R2* MRI, occurred in 21 patients with a phenotype/genotype discrepancy and 15 patients without a discrepancy (84% versus 58%, p=0.048).
Conclusions: The phenotype/genotype discrepancy rate was 49%, unchanged since a similar study in 2013. Because red cell genotyping has not been adopted, no improvement of care in this regard has occurred for thalassaemia patients in Turkey over more than 10 years. We applied an extended antigen matching policy and the alloimmunisation rate approximated 6%. Further studies are needed to determine whether the transfusion of genotypically matched red cells could lead to a decrease in transfusion frequency, helping to prevent iron overload and organ damage.
