title: Relative IgA-deficient recipients have an increased risk of severe allergic transfusion reactions.
abstract: BACKGROUND
  Absolute IgA deficiency is the most common immunodeficiency in the Western world. These patients are at risk of severe allergic reactions when receiving a transfusion with a plasma-containing blood product. However, it is unclear whether patients with relative IgA deficiency, that is levels below detection on routine assays, are also at risk of severe reactions. This retrospective study evaluated the number of severe allergic transfusion reactions in relative IgA-deficient patients who were transfused with unwashed blood products.
  
  
  METHODS
  Patients who had an IgA measurement performed for any reason over a 10-year period were compared with a list of transfusion recipients over the same period. Those who had both an IgA measurement and a transfusion were then compared with the transfusion reaction database to determine whether an allergic reaction had been reported, and if so, the severity of the reaction. Patients with IgA concentrations of <7 mg/dL were defined as relative IgA deficient.
  
  
  RESULTS
  Of the 22 362 IgA measurements performed on 19 737 patients over 10 years, a total of 168 relative IgA-deficient patients were identified; 39 of these patients were also transfusion recipients and 4 of 39 (10%) experienced a severe allergic transfusion reaction (SALTR). Eight SALTRs were reported amongst 1545 (0·52%) IgA replete transfusion recipients.
  
  
  CONCLUSIONS
  The significantly increased risk of SALTRs in relative IgA-deficient patients warrants consideration of premedications and/or washing of plasma-containing blood products.
authors.affiliation: Department of Pathology, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: W
authors.initials: W
authors.lastname: Anani
authors.forename: D
authors.initials: D
authors.lastname: Triulzi
authors.forename: M H
authors.initials: MH
authors.lastname: Yazer
authors.forename: L
authors.initials: L
authors.lastname: Qu
mesh_terms: D000368:Aged; D016913:Blood Component Transfusion / Q000009:adverse effects*; D016208:Databases, Factual; D005260:Female; D006633:Histamine Antagonists / Q000627:therapeutic use; D006801:Humans; D006967:Hypersensitivity / Q000209:etiology*; D017098:IgA Deficiency / Q000097:blood / Q000175:diagnosis*; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D008875:Middle Aged; D011292:Premedication; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D006633:Histamine Antagonists; D007070:Immunoglobulin A
keywords: IgA deficiency; allergic; premedication; reaction; transfusion; washing