Determination of Rh, Kell, Duffy and Kidd phenotypes in addition to ABO is used to prevent the alloimmunization to red blood cells (RBCs) antigens and as part of the antibody identification process in patients with beta Thalassemia. However, phenotyping in these patients can be time consuming and difficult to interpret. In these situations, it would be valuable to have an alternative to hemagglutination tests to determine the patient's antigen profile. We used PCR-RFLP to genotype such patients. DNA was prepared from 50 patients with beta Thalassemia who had been phenotyped by routine hemagglutination, and tested for Kell, Kidd, Duffy/GATA mutation by PCR-RFLP. RHD/non-D was analysed by PCR product size associated to RHD gene sequence in intron 4 and exon 10/3'UTR. The genotyping assays were performed without knowledge of phenotype results. For RHD/non-D, 47 were RhD+ and RHD+/RHCE+, and 3 were RhD- and RHD-/RHCE+. For Kell, 48 kk were K2K2 and 2 Kk were K1K2. For Duffy, of 44 samples that had normal GATA box, 8 Fy(a+b-) were FYA/FYA, 15 Fy(a+b+) were FYB/FYB, and 19 Fy(a+b+) were FYA/FYB; of the other 4 samples 3 were FYA/FYB and heterozygous GATA mutation, and 1 Fy(a-b-) was FYB/FYB, homozygous GATA mutation. Two samples phenotyped as Fy(a+b-) that had normal GATA , presented the 265T/298A mutations and two samples phenotyped as Fy(a-b+) were genotyped was FYA/FYB.. For Kidd , 15 Jk(a+b) were JKA/JKA, 12 Jk(a-b+) were JKB/JKB, and 20 Jk(a+b+) were JKA/JKB. Three samples phenotyped as JK(a+b+) were genotyped as JKB/JKB. Genotype is more accurate than phenotype for determination of blood groups in polytransfused patients with betaThalassemia. Genotyping in these patients can be helpful to select antigen-negative RBCs for transfusion.
Genotyping; blood groups; system
