DEA 1 Expression on Dog Erythrocytes Analyzed by Immunochromatographic and Flow Cytometric Techniques

BACKGROUND: The Dog erythrocyte antigen (DEA) 1 blood group system was thought to contain types DEA 1.1 and 1.2 (and possibly 1.3 [A(3)]). However, DEA 1.2+ dogs are very rare and newer typing methods reveal varying degrees of DEA 1 positivity. OBJECTIVES: To assess if variation in DEA 1 positivity is because of quantitative differences in surface antigen expression. To determine expression patterns in dogs over time and effects of blood storage (4°C). To evaluate DEA 1.2+ samples by DEA 1 typing methods. ANIMALS: Anticoagulated blood samples from 66 dogs in a research colony and from a hospital, and 9 previously typed DEA 1.2+ dogs from an animal blood bank. METHODS: Research study: Samples were analyzed by flow cytometry and immunochromatographic strip using a monoclonal anti‐DEA 1 antibody. RESULTS: Twenty dogs were DEA 1−, whereas 46 dogs were weakly to strongly DEA 1+. Antigen quantification revealed excellent correlation between strip and flow cytometry (r = 0.929). Both methods reclassified DEA 1.2+ samples as weakly to moderately DEA 1+, but they were not retyped with the polyclonal anti‐DEA 1.1/1.X antibodies. Dogs and blood samples retained their relative DEA 1 antigen densities over time. CONCLUSIONS AND CLINICAL IMPORTANCE: The blood group system DEA 1 is a continuum from negative to strongly positive antigen expression. Previously typed DEA 1.2+ appears to be DEA 1+. These findings further the understanding of the DEA 1 system and suggest that all alleles within the DEA 1 system have a similarly based epitope recognized by the monoclonal antibody.