de Chaisemartin L, de la Taille V, Nicaise-Roland P, Malard L, Beuscart C, et al.
Blood •
Allergic transfusion reactions (ATR) are potentially lethal adverse events that occur in ∼0.3% to 6% of plasma or platelet transfusions. The main mechanism described is an immunoglobulin E (IgE)-mediated response to donor proteins, such as IgA and haptoglobin in deficient patients. Recently, in a nationwide retrospective observational study, we reported that group O recipients of group B or AB platelet concentrates or plasma were at significantly higher risk of severe ATR than recipients with other ABO combinations. Given the antigenic proximity between group B determinant and the galactose-α-1,3-galactose (α-Gal) epitope, we hypothesize a role for α-Gal IgE-mediated sensitization in these ATR. In this report, we investigated the presence of anti-α-Gal IgE in a cohort of 59 patients with severe ATR. We found that group O recipients of group B or AB blood components (plasma or platelet concentrates) were substantially more likely to exhibit high titers of group B cross-reactive anti-α-Gal IgE than other patients, supporting our hypothesis that α-Gal sensitization underlies these severe ATR. These findings suggest that α-Gal sensitization is an additional mechanism responsible for ATR in major ABO-incompatible transfusion and should be systematically explored in group O patients having received group B/AB plasma or platelets.
Malard L, Beuscart C, de Chaisemartin L, de la Taille V, Delettre F, et al.
Vox sanguinis •
Severe transfusion reactions to group B-incompatible platelets and plasma possibly related to the α-gal syndrome (AGS) have been recently described. AGS is a potentially severe Immunoglobulin E mediated allergy to mammalian meat and meat-derived products associated with tick bites. The involved allergen, galactose-α-1,3-galactose (α-gal), is antigenically similar to the blood group B antigen. To further assess a potential association between AGS and allergic transfusion reactions (ATRs), we comparatively assessed the frequency of ATRs after plasma or platelet concentrate (PC) transfusion in relation to the degree of ABO compatibility between the recipient and the involved blood component in France. In France, all transfusions are centrally recorded, and ATR reporting is mandatory. Frequencies of severe ATRs involving PC or plasma in relation to ABO group distributions were analysed between 1 January 2022 and 31 December 2024. Among 981,955 PC and 580,230 plasma evaluable transfusions, severe ATRs were significantly higher in group O recipients transfused with group B or AB platelets (relative risk [RR]: 5.06, 95% confidence interval [CI]: 3.27-7.83, p < 0.001) and plasma (RR: 2.15, 95% CI: 1.37-3.36, p < 0.001) while not in group A recipients of group B or AB platelets (RR: 0.95, 95% CI: 0.30-2.96) or plasma (RR: 0.92, 95% CI: 0.45-1.88), when compared to ATR rates in all other recipients of PC or plasma, respectively. In this national retrospective haemovigilance analysis, group B or AB PC or plasma transfused to group O recipients is associated with an increased risk of severe ATRs. Further studies will establish whether AGS is involved in this increased risk.
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. 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. 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%). 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.