title: A high-titer, high-thermal-amplitude autoanti-B associated with acrocyanosis but no obvious hemolytic anemia.
abstract: BACKGROUND
  ABO autoantibodies are rare. Most reported examples have been antibodies with 4 degrees C titers not greater than 256 in patients without apparent hemolytic anemia. Most high-titer, high-thermal-amplitude, complement-activating cold agglutinins are associated with hemolytic anemia.
  
  
  METHODS
  A 52-year-old man presented with acrocyanosis and mild small-vessel brain disease, but no evidence of obvious hemolytic anemia. Regular plasmapheresis treatment was helpful in relieving the clinical symptoms associated with acrocyanosis. Serologic methods were used to study the patient's RBCs and sera.
  
  
  RESULTS
  The patient's RBCs were strongly reactive with anti-C3 and anti-IgM and weakly reactive with anti-IgA. The patient's serum contained a high-titer, high-thermal-amplitude, IgMkappa autoanti-B, capable of activating complement in vitro.
  
  
  CONCLUSIONS
  A patient with a powerful ABO autoantibody is described. This patient had acrocyanosis but did not appear to have an obvious hemolytic anemia. This case is a good example of the lack of correlation between in vitro serologic tests and in vivo reactions in individual patients.
authors.affiliation: American Red Cross Blood Services, Southern California Region, Los Angeles, California, USA. arndtp@usa.redcross.org
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Arndt
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Do
authors.forename: George
authors.initials: G
authors.lastname: Garratty
authors.forename: Mercy A
authors.initials: MA
authors.lastname: Kuriyan
authors.forename: Roger K
authors.initials: RK
authors.lastname: Strair
authors.forename: Akhil
authors.initials: A
authors.lastname: Baranwal
mesh_terms: D000017:ABO Blood-Group System / Q000276:immunology*; D000743:Anemia, Hemolytic / Q000276:immunology; D001323:Autoantibodies / Q000097:blood*; D003176:Complement C3 / Q000032:analysis; D003169:Complement Inactivator Proteins / Q000378:metabolism; D003490:Cyanosis / Q000097:blood / Q000276:immunology* / Q000628:therapy; D004912:Erythrocytes / Q000276:immunology; D005121:Extremities; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007075:Immunoglobulin M / Q000096:biosynthesis; D008297:Male; D008875:Middle Aged; D010956:Plasmapheresis
chemical_list: D000017:ABO Blood-Group System; D001323:Autoantibodies; D003176:Complement C3; D003169:Complement Inactivator Proteins; D007070:Immunoglobulin A; D007075:Immunoglobulin M