Categories: Haematopoietic system phene

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal recessive

Disease-related: no

Key variant known: no

Key variant is published: no

Cross-species summary: Each blood group system consists of a set of blood types, each of which corresponds to a particular antigen (usually a glycoprotein) on the surface of red blood cells. The different types within a system are the result of the action of different alleles at a locus that usually encodes an enzyme that catalyses the creation of the feature of the glycoprotein unique to that type, e.g. the presence of a particular sugar at the end of a short chain of sugars.

Species-specific name: Previously known as Blood Group System A, or canine erythrocyte antigen (CEA) 1 and 2

Species-specific symbol: DEA 1

Inheritance: Symons and Bell (1991) provided convincing family-segregation evidence that the presence of antigen is dominant to its absence, in conformity with our understanding of the biology of blood groups. They also showed a dominance hierarchy of A1 > A2 > A3, meaning that heterozygotes for A1 and A2 exhibit only A1 and heterozygotes for A2 and A3 exhibit only A2.

Clinical features: As reported by Hale (1995): "DEA 1.1 and 1.2 antibody-antigen interactions result in acute hemolytic transfusion reactions." As reported by Hohenhaus (2004): "Reports of transfusion reactions mediated by alloantibodies are infrequent in dogs receiving transfusions, perhaps because of the low frequency of naturally occurring clinically significant antibodies, the rarity of second transfusions in dogs, or more likely underreporting. Retrospective studies of blood transfusions in dog report rates of adverse effects of transfusion between 3% and 13%. [Kerl and Hohenhaus, 1993; Callan et al., 1996]. The most immunogenic of the DEA is 1.1. Transfusion of DEA 1.2–positive erythrocytes into a previously sensitized recipient produces widely variable clinical signs depending on how strongly reactive the antibodies are [Swisher and Young, 1961]. An acute hemolytic transfusion reaction has been described because of an alloantibody against DEA 1.1 [Giger et al., 1995]. Three years before the reported reaction, a DEA 1.1–negative dog received an untyped and unmatched ransfusion for treatment of anemia caused by immune hemolysis. During relapse of the immune-mediated hemolytic anemia, the dog received an emergency transfusion of unmatched red blood cells. One hour later, the dog developed fever, hemoglobinemia, and hemoglobinuria. The recipient was DEA 1.1 negative and the donor DEA 1.1 positive, and it was hypothesized the recipient had been sensitized during the previous transfusion. The alloantibody was of the IgG class and had a hemolysin titer of 1:128 and a hemagglutinin titer of 1:16." More recently, Tocci (2010) reported that "Currently, DEAs 1.1 and 1.2 are considered important in transfusion medicine. DEA 1.1 is known to be extremely antigenic, and DEA 1.1 negative dogs exposed to DEA 1.1 positive RBCs likely become sensitized and produce an anti–DEA 1.1 alloantibody. Subsequent transfusions of DEA 1.1 positive RBC in the DEA 1.1 negative patient result in an acute hemolytic crisis. Therefore, DEA 1.1 is the antigen routinely determined in patients and donors, and 42% of the canine population is positive.[Hohenhaus, 2004]. An acute hemolytic transfusion reaction (AHTR) has been reported in a DEA 1.1 negative dog, which had developed antibodies to DEA 1.1 from a previous transfusion of DEA 1.1 positive RBC.[Giger et al., 1995]"