AM25-TU-12-L - Alpha-Gal Syndrome: Can Tick Bites Lead to Life-Threatening Allergic Transfusion Reactions?

Tuesday, October 28, 2025

9:30 AM - 11:00 AM PT

Location: 29

Speaker(s)

Richard M. Kaufman, MD

Professor of Pathology and Laboratory Medicine
Dartmouth Geisel School of Medicine
Lebanon, Vermont

Disclosure(s): No financial relationships to disclose

Program Chair(s)

Nancy M. Dunbar, MD (she/her/hers)

Professor of Pathology and Laboratory Medicine
Dartmouth Geisel School of Medicine
Lebanon, New Hampshire

Disclosure(s): No financial relationships to disclose

Speaker(s)

Nancy M. Dunbar, MD (she/her/hers)

Professor of Pathology and Laboratory Medicine
Dartmouth Geisel School of Medicine
Lebanon, New Hampshire

Disclosure(s): No financial relationships to disclose
Scott P. Commins, MD, PhD

William J. Yount Distinguished Professor of Medicine
University of North Carolina
Chapel Hill, North Carolina

Disclosure(s): No relevant disclosure to display

Proposed Session Description: Galactose-𝛼-1,3-galactose, or 𝛼-gal, is an oligosaccharide expressed on the cell membranes of most mammals. Humans do not express alpha-gal. Alpha-gal is highly immunogenic, and all humans have naturally occurring alpha-gal IgM, IgG, and IgA--but not IgE.

Alpha-gal syndrome mainly refers to an acquired food allergy that has been observed worldwide. Individuals with alpha-gal syndrome characteristically develop allergic signs and symptoms 3-6 hours after eating mammalian meat. The clinical picture ranges from mild (hives) to severe (anaphylaxis, sometimes fatal). Remarkably, strong evidence has emerged demonstrating that alpha-gal syndrome develops following tick bites. In the U.S., Amblyomma americanum (the lone star tick) is the cause of alpha-gal syndrome. In other regions, other tick species are the culprit. After being bitten by a tick, some individuals form alpha-gal IgE, which primes them for allergic reactions upon subsequent exposure to alpha-gal antigens.

Recent evidence suggests that patients with alpha-gal IgE may be at risk for severe or even fatal allergic transfusion reactions if they receive plasma or platelet units containing B antigen, which is structurally related to alpha-gal. This session will review current research on transfusion-related alpha-gal syndrome and discuss potential implications for future transfusion practices.

Scott Commins MD, PhD will provide an overview of the biology, epidemiology, and non-transfusion-related clinical manifestations of alpha-gal syndrome.

Richard Kaufman MD will review a recent case of probable transfusion-related alpha-gal syndrome and describe a new multicenter study designed to obtain epidemiological evidence supporting or refuting a link between alpha-gal syndrome and allergic transfusion reactions.

Nancy Dunbar MD will discuss the contemporary use of non-ABO-identical platelet and plasma transfusions and will explain how transfusion-related alpha-gal syndrome may impact hospital transfusion services in the future.

Learning Objectives:

Discuss the biological underpinnings of alpha-gal syndrome, a widespread and unusual immune syndrome that can develop following tick bites.
Analyze the current data suggesting that severe allergic transfusion reactions among recipients of group B/AB platelets or plasma may represent a newly recognized manifestation of alpha-gal syndrome.
Evaluate the potential impact on patient safety and transfusion service practices should concrete changes be necessary to mitigate the risks of transfusion-related alpha-gal syndrome.