Prevalence of Dog Erythrocyte Antigens 4 and 7 in Italian Canine Blood Donors Using Gel Agglutination Technique

Blood typing of canine blood donors is a prerequisite for transfusion purposes. Dog erythrocyte antigen (DEA) 1 is the most antigenic blood type and rapid and accurate commercial assays are available. Other blood types are also important in selection of appropriate donors. The aim of this study was to determine the prevalence of DEA 4 and 7 antigens in canine blood donors from three university transfusion centers in: Milan, Pisa and Perugia, using gel agglutination technique. Eighty-four dogs representing a variety of breeds were enrolled (with owner consent): 30 males and 54 females, mean ± SD age 4.6 ± 2.0 years (range 1–8 years), mean ± SD ht 47 ± 6.0% (range 31–61%); 34 dogs (40.5%) were DEA 1 positive (identified using card agglutination or immunochromatographic methods). Analysis for DEA 4 and 7 was carried out by gel column card agglutination within microtubes utilizing polyclonal anti-DEA antibodies. Briefly 25 μl of 0.8% RBC suspension (made by suspending 10 μl of the RBC pellet in 1 ml of low ionic strength solution) was mixed with 25 μl of DEA 7 antibodies or with 15 μl of DEA 4 antibodies in the reaction chamber of saline gel columns. For all samples, a negative control column with saline was included. The gel columns were incubated at 4°C for 30 minutes and then centrifuged in a special gel column card centrifuge at 80 g for 10 minutes. Finally, the gel column cards were visually interpreted for presence and strength of agglutination from (0) negative, when all RBCs were at the bottom of the column to 4+, when all RBCs formed a red line on top of the gel. Results were interpreted as negative if no or 1+ agglutination was present, whereas ≥ 2+ agglutination reactions were considered positive. Using this method, blood type was determined in all blood samples and all control samples were negative. There were 84 (100%) DEA 4 positive dogs (all 4+ agglutination) and 28 (33.3%) DEA 7 positive dogs (#18, 2+ agglutination; #9, 3+ agglutination; #1, 4+ agglutination). Thirty-two (38.1%) dogs were categorised as ideal donors (i.e., DEA 1 and 7 negative). The prevalence of DEA 4 and 7 in these canine blood donors was comparable with data previously published: with all dogs, DEA 4 positive and one third of dogs DEA 7 positive. Agglutination on gel column is a simple, easily interpreted and rapid method to determine DEA 4 and 7 blood types.