ABO and RH1 blood group phenotyping in pigs (Sus scrofa) using microtyping cards

Transplantation or transfusion with ABO disparity is a cause for rejection or for severe hemodynamic alterations. ABO groups in pigs are commonly an unknown variable, which has been previously assessed by means of hemagglutination tests or immunohistochemical procedures on tissues. Herein, we have reported a simple method using commercial microcards for human ABO typing. However, the reagents directly derived from human sera included in these cards can result in false determinations due to alpha-gal interference. The ABO groups of 19 wild-type pigs (Landrace x Large White) were assessed using 2 commercial cards: Human sera-based and monoclonal antibody-based cards. The human sera cards determined that 8 pigs belonged to the AB group and 11 to the B group. The monoclonal antibody cards determined that 8 pigs belonged to the A group and 11 to the O group. None of the pigs showed reactions to Rh1 antibodies. Because the B group has not been described in pigs, the reaction in human sera cards represented an interference with alpha-gal antigen, a molecule structurally similar to the B blood antigen. Thus, microtyping cards based on monoclonal antibodies provided simple, quick way to assess ABO groups in pigs used for xenotransplantation. ABO concordance should always be investigated for these types of procedures.