Alpha-gal syndrome linked to dangerous blood transfusion reactions

A study published in JAMA Internal Medicine has identified a link between alpha-gal syndrome (AGS) and dangerous allergic reactions during blood transfusions. Researchers from Dartmouth Health and the Geisel School of Medicine have termed this phenomenon Transfusion-Related Alpha-Gal Syndrome (TRAGS).

Alpha-gal syndrome is a condition triggered by bites from certain ticks, such as the Lone Star tick, which causes the immune system to produce antibodies against alpha-gal, a sugar molecule found in most non-primate mammals. While typically associated with allergic reactions to red meat, pork, and dairy, the study suggests these antibodies may also react to certain blood products.

Clinical observations at Dartmouth Hitchcock Medical Center noted an increase in severe reactions among patients with type O blood when they received platelets or plasma from donors with type B or AB blood. This is hypothesized to occur because the B blood-group antigen is structurally similar to alpha-gal. An international analysis of over 558,000 transfusions across 40 hospitals documented 1,744 allergic reactions related to this issue.

In response to these findings, Dartmouth Hitchcock Medical Center has ceased providing B or AB platelets to type O patients to prevent injury. Researchers expect these findings to influence transfusion safety practices, particularly in regions with high prevalence of alpha-gal syndrome.