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Prevalence of dog erythrocyte antigen (DEA) 1 amongst the dog blood donors at Tamil Nadu veterinary and animal sciences university animal blood bank (TABB), India

Dogs do not have natural dog erythrocyte antigen (DEA) antibodies but are eventually sensitized following the first incompatible transfusion.1 The knowledge of the canine blood groups, immunogenicity and incompatibility is clinically useful to carry out safe transfusions without risk of sensitization or the risk of developing a transfusion reaction.2 Even if the multiple transfusions are increasing in India, compared to the western countries, the determination of the blood group antigens in dogs using DEA typing kits or anti-sera are considerably minor because of seldom repeated transfusions to the same recipient dog.


Introduction
Dogs do not have natural dog erythrocyte antigen (DEA) antibodies but are eventually sensitized following the first incompatible transfusion. 1 The knowledge of the canine blood groups, immunogenicity and incompatibility is clinically useful to carry out safe transfusions without risk of sensitization or the risk of developing a transfusion reaction. 2 Even if the multiple transfusions are increasing in India, compared to the western countries, the determination of the blood group antigens in dogs using DEA typing kits or anti-sera are considerably minor because of seldom repeated transfusions to the same recipient dog.
Nowadays, there have been various groups and theories that define a universal dog blood donor. It has been reported that the universal dog blood donor should be negative for DEA 1 and DEA 7, and positive for DEA 4. In all practical aspects, the dog with the absence of the highly antigenic DEA 1 is considered to be a safe donor. 3 An international standardization committee has designated the DEA system where the dogs are either positive or negative for most of the DEAs, the DEA 1 system contains 4 alleles, with different levels of antigenic expressions from strong (4+) to weak (1+) DEA 1. 4,5 The most frequently studied breeds were German shepherd, Golden Retriever, Greyhound, Doberman, and Rottweiler along with investigations in mongrel dogs. [6][7][8] Since the knowledge of prevalence of DEA 1 in different breeds is important for the recruitment of typed compatible blood donors. The aim of the study was to describe the prevalence of DEA 1 amongst the registered dog blood donors at the TANUVAS Animal Blood Bank, Chennai, India.

Materials and methods
One-hundred and twenty-five purebred and mongrel dog blood donors from to the Madras Veterinary College, Chennai were typed for the DEA 1 blood group during the period of time ranging from January 2010-January 2011. All samples were tested previously in saline agglutination test to determine the presence of auto-agglutination. The positive samples were excluded from further investigations.
Blood typing was carried-out with the Alvedia Lab DEA 1 Kit (Lyon, France). This in-house kit is based on the migration of red blood cells on a membrane previously treated with a buffer and incorporated with a monoclonal antibody highly specific to the Dog Erythrocyte Antigen. One drop of whole blood was added to the 3 drops of DEA buffer into the typing kit, the membrane containing the monoclonal antibody was placed into it, the result was read after two minutes. Erythrocytes positive for DEA 1 are captured by this antibody and a red line on the mid portion of this membrane is showed. The blood group results are reported using only a descriptive statistics.

Results
The obtained results of presence of DEA 1 blood group in the random dog blood donor population in TANUVAS Animal Blood Bank; Chennai, India is 61.6% (Table 1).

Discussion
In this study 125 dog blood donors, 77 (61.6%) were DEA 1 positive and 38,4 % were DEA 1 negative. The prevalence for DEA1 positive dogs found in this study was very similar to results reported in other studies carried out in the world (53 to 65% for DEA 1 positive). 8,9 There are not enough studies showing the prevalence of DEA 1 in India, however a recent study indicates a 78% of DEA 1 positive in dogs of the Punjab city, this result could be influenced by the presence of a majority of breeds with a high prevalence of DEA 1 positive. 10 A recent study with a high number of dogs tested (7,414) reported in Italy, shows a very similar prevalence of DEA 1 positive to this blood bank donors (61,2%). 11 In 1996 Hale, described a prevalence of 63.5% for DEA 1. The difference in the DEA 1 prevalence in the world is generally due to the sampling of the tested dogs. The documented clinical case of a DEA 1 negative dog previously sensitized with DEA 1 blood group, emphasized the importance of canine blood type DEA 1.1 concerning to blood transfusion incompatibility. 2 It supported the recommended practice of cross-matching dogs, particularly prior to a second transfusion, and the use of blood donors, which are DEA 1.1 negative. Kessler et al., 7 reported that in dogs, the lack of alloantibodies that occur naturally and clinically relevant may preclude the need for having extended type-specific blood available for a first transfusion. 7 But, since there is a risk of sensitization with the presence of antibodies that can appear within 4-14 days, in DEA 1 negative dogs who received blood from DEA 1 positive dogs following the first transfusion, blood typing to identify the presence of DEA 1 and the cross-match to establish full compatibility should be performed before each transfusion. 1,3,12-16

Conclusion
The obtained results of DEA 1 in the random dog blood donor population in India are 61.6% which is similar to those reported in worldwide by the western countries.
Because of the DEA 1 blood groups represents the most immunogenic blood group, it is mandatory for the veterinary practice in India to carry out blood typing to identify the presence of DEA 1 antigen and the major and minor cross-match before each transfusion. Also, DEA 1 blood group should be typed in the Indian native dog breeds to determine the prevalence of positive and negative dogs to ensure safe transfusions.

Ethical approvals
The studies were carried out in accordance with the Guidelines laid down by the International Animal Ethics Committee or Institutional Ethics Committee and in accordance with local laws and regulations and proper consent from the clients.