title: An inquiry into the relationship between ABO blood group and thrombotic thrombocytopenic purpura.
abstract: OBJECTIVE
  ABO blood group accounts for up to 40% of the variability in plasma von Willebrand factor (VWF) levels, which vary in the rank order AB > B > A > O > Bombay. This may be due in part to the influence of ABO-associated oligosaccharides on the proteolysis of VWF by the metalloprotease ADAMTS13, which is markedly deficient in thrombotic thrombocytopenic purpura (TTP). Using ABO blood group as a surrogate for baseline VWF levels as well as susceptibility to proteolysis by ADAMST13, we set out to determine whether ABO blood group influences the clinical course of TTP.
  
  
  METHODS
  We conducted a retrospective analysis of the clinical course of 76 patients with primary, sporadic TTP treated at two institutions over the past 10 years.
  
  
  RESULTS
  We found no significant differences between group O and non-O patients with respect to presenting platelet count and lactate dehydrogenase concentration, maximum serum creatinine concentration, and total number of therapeutic plasma exchanges per episode.
  
  
  CONCLUSIONS
  Substrate-related contributors to the highly variable phenotype and clinical course of TTP warrant further investigation.
authors.affiliation: Department of Pathology, Massachusetts General Hospital, Boston, MA, USA.
authors.forename: J F
authors.initials: JF
authors.lastname: Staropoli
authors.forename: C P
authors.initials: CP
authors.lastname: Stowell
authors.forename: H H
authors.initials: HH
authors.lastname: Tuncer
authors.forename: M B
authors.initials: MB
authors.lastname: Marques
mesh_terms: D000017:ABO Blood-Group System / Q000097:blood*; D051722:ADAM Proteins / Q000097:blood; D000071120:ADAMTS13 Protein; D000328:Adult; D005260:Female; D006801:Humans; D008297:Male; D011697:Purpura, Thrombotic Thrombocytopenic / Q000097:blood* / Q000201:enzymology / Q000628:therapy; D012189:Retrospective Studies; D014841:von Willebrand Factor / Q000032:analysis / Q000378:metabolism*
chemical_list: D000017:ABO Blood-Group System; D014841:von Willebrand Factor; D051722:ADAM Proteins; D000071120:ADAMTS13 Protein; C099604:ADAMTS13 protein, human