Phenotypic and Genetic Characterization for Incompatible Cross-Match Cases in the Feline AB Blood Group System.

Yumiko Uno,Karin Yoshida,Chihiro Nakamura,Kazuhiko Ochiai,Tasuku Kobayashi,Toshinori Omi,Eri Onozawa,Chihiro Udagawa,Masami Yaguchi

doi:10.3389/fvets.2021.720445

Abstract

The feline AB blood group system (blood types A, B, and AB) encoding the cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH) gene is the most significant in transfusion medicine and hemolysis of the newborn for cats. Blood typing and cross-matching in pre-transfusion testing are crucial to determining blood compatibility and thus prevent hemolytic transfusion reactions. We here performed serological and genetic investigations to characterize blood samples from cats with discordant results for card agglutination (CARD) and the alloantibody agglutination test for blood typing in two cats (subjects K and R). Subject K showed incompatible cross-matching in pre-transfusion testing. Red blood cells from subjects K and R determined blood type B from the CARD method showed blood type AB by alloanti-A and alloanti-B antibodies in agglutination testing. Genomic DNA sequencing of the coding region (exons 1a to 14) for the cat CMAH gene showed that subject K had four mutations with heterozygosity at c.139C>T, c.179G>T, c.327A>C, and c.364C>T. Similarly, the CMAH gene of subject R carried six mutations with heterozygosity at c.142G>A, c.187A>G, c.268T>A, c.327A>C, c.773G>A and c.1603G>A, representing a new diplotype including a novel synonymous single nucleotide polymorphism (SNP) in exon 7 (c.773 G>A: Arg258Gln). The CMAH diplotype in subjects K and R was different from major diplotype in blood type B cats. This study is the first to report CMAH variants in cats with discordant blood types between CARD and TUBE methods. These results could assist in the classification of feline AB blood types for transfusion medicine to avoid blood incompatibilities.

Highlights

AB blood group antigens are the most significant in transfusion medicine and neonatal isoerythrolysis (NI) for cats [1,2,3,4,5]
We regard that double haploids selected from multiple recessive alleles carrying one or several of these single nucleotide polymorphism (SNP) are presumed to lead to a loss or reduction of enzyme activity for synthesizing Neu5Gc from Neu5Ac, and would be associated with expression of Neu5Ac on the erythrocyte membrane in type B and AB cats [15]
We describe the detection of an incompatible cross-match case in the feline AB blood group system, and another cat with discordant results from the card agglutination (CARD) method and alloantibody agglutination test for blood typing

Summary

Introduction

AB blood group antigens are the most significant in transfusion medicine and neonatal isoerythrolysis (NI) for cats [1,2,3,4,5]. The feline AB blood group system is based on A and B antigens and contains type A, type B, and the rare type AB. Type AB erythrocytes express both Neu5Gc and Neu5Ac, and cats of this type show no naturally occurring antibodies to blood types A or B [2]. The enzyme cytidine monophosphate-N-acetylneuraminic acid hydroxylase is encoded by the CMAH gene, which changes Neu5Ac to Neu5Gc [8, 9]. We regard that double haploids selected from multiple recessive alleles carrying one or several of these SNPs are presumed to lead to a loss or reduction of enzyme activity for synthesizing Neu5Gc from Neu5Ac, and would be associated with expression of Neu5Ac on the erythrocyte membrane in type B and AB cats [15]

Methods

Results

Conclusion