Global gene expression reveals an increase of HMGB1 and APEX1 proteins and their involvement in oxidative stress, apoptosis and inflammation pathways among beta-thalassaemia intermedia and major phenotypes.

Beta-thalassaemia (BT) is classified according to blood transfusion requirement as minor (BTMi), intermedia (BTI) and major (BTM). BTM is the most severe form, requiring regular transfusions while transfusion need is only occasional in BTI. Differential gene expression between patients has not been assessed so far. Here, we evaluated the global gene expression profiles during differentiation of human erythroid cells of two patients carrying the same mutation [CD39, (C → T)], though displaying different phenotypes (BTI and BTM). Considering the role of reactive oxygen species (ROS) in the pathophysiology of thalassaemia, we focused on differentially expressed genes involved in metabolic pathways triggered by ROS, such as inflammation and apoptosis, and, from these, we selected the Apurinic/Apyrimidinic Endodeoxyribonuclease 1 (APEX1) and High Mobility Group Box1 (HMGB1) genes, whose role in BT is not well established. An in-depth expression analysis of transcriptional and protein levels in patients carrying a range of mutations associated with BT phenotypes indicated that APEX1 was increased in both BTI and BTM. Furthermore, higher amounts of HMGB1 was found in the plasma of BTI patients. Our findings suggest that these proteins have important roles in BT and could represent new targets for further studies aiming to improve the management of the disease.

Blood group genotyping facilitates transfusion of beta-thalassemia patients.

We evaluated the usefulness of blood group genotyping as a supplement to hemagglutination to determine the red blood cell (RBC) antigen profile of polytransfused patients with beta-thalassemia. We selected 10 alloimmunized patients who were receiving antigen-matched RBCs based on phenotype, and had clinical evidence of delayed hemolytic transfusion reaction. DNA was prepared from blood samples and RH E/e, K1/K2, FY A/FY B, and JK A/JK B alleles were determined by PCR-RFLP. RH D/non-D was determined according to the PCR product size associated with the RHD gene sequence in intron 4 and exon 10/3'UTR. RH C/c was tested by multiplex PCR. The phenotypes and genotypes of nine of the 10 samples were discrepant. Five of the discrepancies occurred in the Rh system. One sample was phenotyped as Rhcc and genotyped as RH C/C, and two samples were phenotyped as RhCc and genotyped as RH C/C. Two other samples were phenotyped as RhEe and genotyped as RH e/e. Three samples had discrepancies in the Kidd system with phenotype Jk(a+b+) and were genotyped as homozygous for JK B. One sample had a discrepancy in the Duffy system: it was phenotyped as Fy(a+b-) and homozygous for FY B. Genotyping was very important in determining the true blood groups of many polytransfused patients with beta-thalassemia, and it assisted in the identification of suspected alloantibodies and the selection of antigen-negative RBCs for transfusion.