ABSTRACT
OBJECTIVES: This study evaluated the red blood cell (RBC) Lewis phenotypes by simple haemagglutination technique and molecular genotyping in healthy individuals. BACKGROUND: The expression of Lewis antigen on RBCs is dependent on the interaction of FUT3 and FUT2 genes. Complexity of the genetic control of Lewis antigen expression and the error-prone nature of Lewis phenotyping result in non-genuine RBC Lewis phenotypes, which could be misleading. MATERIALS AND METHODS: ABO blood group and RBC Lewis phenotypes were determined by conventional haemagglutination tube techniques. FUT2 and FUT3 genotypes were analysed by polymerase chain reaction and direct DNA sequencing. The RBC Lewis phenotypes were also inferred from the FUT2 and FUT3 genotyping results. RESULTS: The frequencies of RBC Lewis phenotypes typed by the conventional tube test were Le(a+b-) 19.63%, Le(a-b+) 49.32% and Le(a-b-) 31.05%, whereas the frequencies inferred from the FUT2 and FUT3 genotypes were Le(a+b-) 20.09%, Le(a-b+), 59.82%; Le(a-b-), 17.81%; and Le(a+b+), 5 (2.28%). The Le(a+b+) phenotype was not detected by the tube test, and a significant difference was observed in the frequencies of the determined Le(a-b-) and Le(a-b+) phenotypes. CONCLUSION: The phenotyping and genotyping of Lewis blood group system reveal a high rate of discordance in the frequencies of Lewis phenotypes among the healthy individuals.
Subject(s)
Blood Grouping and Crossmatching/methods , Erythrocytes/immunology , Fucosyltransferases/genetics , Genotyping Techniques/methods , Lewis Blood Group Antigens/genetics , Phenotype , Adolescent , Adult , Aged , Female , Genetic Markers , Genotype , Healthy Volunteers , Humans , Male , Middle Aged , Polymerase Chain Reaction , Reproducibility of Results , Sequence Analysis, DNA , Young Adult , Galactoside 2-alpha-L-fucosyltransferaseABSTRACT
The blood specimen of a 30-year-old male donor showing a discrepancy in cell and serum grouping was targeted for detailed study at the blood bank at tertiary care hospital in South Gujarat. Forward grouping showed group as "O" RhD positive and reverse grouping as group "A." Further testing confirmed that the individual's blood group was para-Bombay A (para-AH). Family members were screened, and younger brother was also identified as para-Bombay phenotype. The para-Bombay phenotype is very rare, and only a few cases have been reported from India. This blood group is characterized by the absence of ABH antigens on red blood cells (RBC's) with the presence of ABH substances in body secretions or by the weak expression of ABH antigens on RBC's with the absence or presence of substances in body secretions. This rare phenotype can be mislabeled as "O" if all detailed investigations are not performed.
