Identification of a Rare Ael05/B101 Subtype and Selection of Blood Transfusion Strategy

Abstract

To explore the mechanism of ABO discrepancy in a patient by ABO genotyping and the reasonable blood transfusion strategy. Routine serological test was carried out to analyze ABO blood group. The presence of the blood group determinants on the red blood cells were determined by adsorption-elution test. Exons 1-7 and adjacent introns of the ABO gene were amplified by PCR and sequenced. The patient showed ABO forward and reverse typing discrepancy. ABO forward typing defined as B, however, the reverse typing indicated that the patient was AB subtype. Absorption-elution test confirmed weak A antigens on the patient's red blood cells. The ABO gene sequencing showed a T>C exchange at position in exon 7 which resulted in a isoleucine to threonine substitution at codon 256. The ABO blood group genotype was ABO*Ael05/B101. The 767 T>C substitution in the gene of α-1,3-N-acetyl galactose is the molecular mechanism leading to the decrease expression of A antigen of the Ael05 subtype.