BLOOD-TYPE AB IN THE FELINE AB BLOOD-GROUP SYSTEM

Objective-To assess the genetics, frequency, and biochemistry of the A B blood type in cats. Animals-Domestic shorthair and purebred cats in a breeding colony and privately owned catteries and blood samples from a large feline blood typing laboratory. Procedures-Samples from cats with blood type AB were selected from the feline blood typing laborato ry at the university. Breeding experiments and family studies were use d for the genetic analysis of cats with blood type AB. Simple slide he magglutination assays were used To type cats. Hemagglutination assays, flow cytometry, and ganglioside analysis by high-performance thin lay er chromatography were applied to characterize the AB antigens. Result s-Type AB was rare (13/9,239 cats; 0.14% frequency) in cats of the Uni ted Slates and Canada. Type AB occurred only in breeds in which type B was also detected. Cats with type-AB blood express biochemical featur es of type-A and type-B antigens, Genetic analyses of families with bl ood type-AB cats are consistent with the hypothesis of 3 alleles: A, B , and AB. The AB allele is recessive to the A allele, but dominant ove r the B allele. There may be an additional genetic mechanism responsib le for the inheritance of blood type AB in cats. Conclusion-Blood type AB is an extremely rare and separately inherited type in the feline A B blood group system. Clinical Relevance-Kittens with type-AB blood bo rn to queens with type-B blood are al similar risk for neonatal isoery throlysis as kittens with type-A blood because anti-A alloantiserum fr om blood type-B queens recognizes AB red blood cells. Furthermore, cat s with type-AB blood are best transfused with type-AB or type-A blood.