title: Plasma levels of prekallikrein, alpha-2-macroglobulin and C1-esterase inhibitor in patients with urticarial reaction to contrast media.
abstract: OBJECTIVE
  The plasma levels of prekallikrein, alpha-2-macroglobulin and C1-esterase inhibitor (C1 INH) in patients with previous urticarial reaction to contrast media (CM) were compared to those of a group of nonreacting age- and sex-matched controls. This study evaluated the value of these laboratory variables in predicting acute and delayed urticarial-type reactions.
  
  
  METHODS
  The study comprised 44 patients (reactors) with acute (n = 29) or delayed (n = 15) urticaria after administration of CM, and a group of age- and sex-matched controls.
  
  
  RESULTS
  In the reactors, the levels of prekallikrein and alpha-2-macroglobulin were higher (p < 0.0001) and the level of C1 INH lower (p < 0.0001) than those of the controls. The level of prekallikrein decreased with increasing age (p = 0.02) and women had higher values than men (p = 0.0054). The level of alpha-2-macroglobulin was age-dependent (p = 0.006).
  
  
  CONCLUSIONS
  Although high plasma prekallikrein activity, high plasma alpha-2-macroglobulin activity, and low plasma C1 INH activity are associated with urticaria-type reaction to CM, their value in predicting urticarial reaction is limited because prekallikrein is age- and sex-dependent, and alpha-2-macroglobulin is age-dependent.
authors.affiliation: Department of Radiology, Helsinki University Central Hospital, Finland.
authors.forename: R
authors.initials: R
authors.lastname: Mikkonen
authors.forename: H J
authors.initials: HJ
authors.lastname: Aronen
authors.forename: L
authors.initials: L
authors.lastname: Kivisaari
authors.forename: A
authors.initials: A
authors.lastname: Piilonen
authors.forename: M
authors.initials: M
authors.lastname: Syrjälä
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016022:Case-Control Studies; D003174:Complement C1 Inactivator Proteins / Q000032:analysis*; D003287:Contrast Media / Q000009:adverse effects*; D004342:Drug Hypersensitivity / Q000209:etiology*; D005260:Female; D005544:Forecasting; D006801:Humans; D006968:Hypersensitivity, Delayed / Q000139:chemically induced; D006969:Hypersensitivity, Immediate / Q000139:chemically induced; D008297:Male; D008875:Middle Aged; D011288:Prekallikrein / Q000032:analysis*; D011336:Probability; D012737:Sex Factors; D014581:Urticaria / Q000097:blood* / Q000139:chemically induced; D000511:alpha-Macroglobulins / Q000032:analysis*
chemical_list: D003174:Complement C1 Inactivator Proteins; D003287:Contrast Media; D000511:alpha-Macroglobulins; D011288:Prekallikrein