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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.
Lopes DMS, Lima JMS, Ribeiro KSM, Gomes CF, Rocha RM, et al.
Parasitology •
The challenge of American tegumentary leishmaniasis (ATL) continues in Brazil, presenting a persistent public health issue despite initiatives aimed at public outreach, vector control and health education. To gain a deeper understanding of this disease, a study was conducted in an endemic region located in the northern region of the state of Minas Gerais, Brazil. The study monitored 30 resident patients diagnosed with ATL, using serum samples from 6 healthy individuals as controls. The localized cutaneous form of the disease was found to be predominant, with lesions appearing on various parts of the body and the majority of the affected individuals being male. The study found significantly higher levels of IgG anti--Gal antibodies in ATL-infected patients compared to healthy individuals. Treatment of 19 patients with meglumine antimoniate resulted in limited improvement in symptoms for most. Nonetheless, the study found that 12 patients who completed treatment with epithelialization of the lesions showed a significant decrease in IgG anti--Gal antibodies, indicating potential applications of this antibody in the diagnosis and monitoring of the disease. The study also identified species in 7 analysed patients, revealing 6 cases infected by and 1 by , with a significant difference in the anti--Gal responses. The findings of the study emphasize the urgent need for the development of human vaccines and innovative treatment strategies adapted to the diversity of species causing cutaneous leishmaniasis and individual patient responses to improve the clinical management of ATL in Brazil and similar endemic regions.