ABO‐mismatched platelet and plasma transfusion practices and the potential for transfusion‐related alpha‐gal syndrome: The Biomedical Excellence for Safer Transfusion Collaborative Study

Abstract Background Alpha‐gal syndrome (AGS) is caused by IgE antibodies against the alpha‐gal oligosaccharide, which is structurally similar to the Group B antigen. Recent case reports of severe allergic transfusion reactions (ATRs) in Group O patients receiving Group B plasma and platelets raise the possibility of a new adverse event, herein called transfusion‐related AGS (TRAGS). The primary goal of this study was to assess the frequency of Groups B and AB plasma and platelet transfusions to Group O patients. Study Design and Methods In this multi‐site retrospective study, participating sites submitted the numbers of platelet and plasma transfusions administered during a 2‐year period categorized by patient and product ABO group. Results Fourteen sites from 10 countries participated. Group O patients received Group AB for an average of 9.9% (range 2.8%–29.2%) of plasma transfusions and Group B for 3.2% (0%–12.8%). AB plasma transfusion to Group O patients represented 4.5% (0.9%–14.6%) of the total plasma transfused; Group B 1.4% (0%–5.1%). Group O patients received Group AB for an average of 1.5% (range 0%–5.9%) of platelet transfusions and Group B for 4.1% (0%–14.2%). AB platelet transfusion to Group O patients represented 0.6% (0%–2.7%) of the total platelets transfused; Group B platelets were 1.8% (0%–6.7%). Discussion Evidence supporting the possibility of a new adverse event, TRAGS, is accumulating. This study quantifies how often Group O patients may be exposed to Group B antigen in Group B or AB plasma and/or platelet transfusions, providing an estimate of the scope of potential risk for TRAGS.