title: A newly recognized blood group in domestic shorthair cats: the Mik red cell antigen.
abstract: BACKGROUND
  Naturally occurring alloantibodies produced against A and B red cell antigens in cats can cause acute hemolytic transfusion reactions. Blood incompatibilities, unrelated to the AB blood group system, have also been suspected after blood transfusions through routine crossmatch testing or as a result of hemolytic transfusion reactions.
  
  
  OBJECTIVE
  Incompatible crossmatch results among AB compatible cats signify the presence of a naturally occurring alloantibody against a newly identified blood antigen in a group of previously never transfused blood donor cats. The associated alloantibody is clinically important based upon a hemolytic transfusion reaction after inadvertent transfusion of red cells expressing this red cell antigen in a feline renal transplant recipient that lacks this red cell antigen.
  
  
  METHODS
  Blood donor and nonblood donor cats were evaluated for the presence of auto- and alloantibodies using direct antiglobulin and crossmatch tests, respectively, and were blood typed for AB blood group status. Both standard tube and novel gel column techniques were used.
  
  
  RESULTS
  Plasma from 3 of 65 cats and 1 feline renal transplant recipient caused incompatible crossmatch test results with AB compatible erythrocytes indicating these cats formed an alloantibody against a red cell antigen they lack, termed Mik. The 3 donors and the renal transplant recipient were crossmatch-compatible with one another. Tube and gel column crossmatch test results were similar.
  
  
  CONCLUSIONS
  The absence of this novel Mik red cell antigen can be associated with naturally occurring anti-Mik alloantibodies and can elicit an acute hemolytic transfusion reaction after an AB-matched blood transfusion.
authors.affiliation: Section of Medical Genetics, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010, USA.
authors.forename: Nicole M
authors.initials: NM
authors.lastname: Weinstein
authors.forename: Marie-Claude
authors.initials: MC
authors.lastname: Blais
authors.forename: Kimberly
authors.initials: K
authors.lastname: Harris
authors.forename: Donna A
authors.initials: DA
authors.lastname: Oakley
authors.forename: Lillian R
authors.initials: LR
authors.lastname: Aronson
authors.forename: Urs
authors.initials: U
authors.lastname: Giger
mesh_terms: D000818:Animals; D001789:Blood Group Antigens / Q000235:genetics*; D002415:Cats / Q000097:blood*; D005260:Female; D007518:Isoantibodies / Q000097:blood; D008297:Male
chemical_list: D001789:Blood Group Antigens; D007518:Isoantibodies