Overview
- The Dartmouth‑led study, published Aug. 24, analyzed more than 550,000 platelet and plasma transfusions from 40 sites in five countries and found a significant excess of allergic reactions at nine U.S. sites with high alpha‑gal syndrome (AGS) prevalence.
- Researchers reported that type O patients who received platelets or plasma from type B or AB donors had higher rates of allergic transfusion reactions than O‑to‑O transfusions in those high‑prevalence centers.
- Dartmouth Hitchcock Medical Center has already stopped giving B or AB platelet units to type O patients as a precaution, and the study authors urged other hospitals in AGS‑affected areas to consider similar steps.
- Alpha‑gal is a sugar introduced by Lone Star tick bites that can produce anti–alpha‑gal antibodies; those antibodies can react to mammalian products in donor plasma or platelets and trigger delayed, sometimes severe, allergic responses.
- The finding raises practical questions for blood services about inventory management, possible donor or recipient antibody screening, and balancing safety measures against blood‑supply limits as climate‑driven tick spread likely expands AGS risk.