Alpha-gal syndrome
Symptoms of the allergy vary greatly between individuals and include rash, hives, nausea or vomiting, difficulty breathing, drop in blood pressure, dizziness or faintness, diarrhea, severe stomach pain, and possible anaphylaxis.
[4] Anti-gal is a human natural antibody that interacts specifically with the mammalian carbohydrate structure gal alpha 1-3Gal beta 1-4GlcNAc-R (the alpha-galactosyl epitope).
[5] The alpha-gal molecule is found in all mammals except catarrhines (apes and Old World monkeys),[5] the taxonomic branch that includes humans.
[13][15] A typical allergic reaction to alpha-gal has a delayed onset, occurring 3–8 hours after consuming mammalian meat products.
[3] It has been found that other factors, including exercise and alcohol consumption, can potentially affect an individual's symptoms and overall reactivity to alpha-gal.
[23] Only a small percentage of children and adults will acquire a red meat allergy after receiving a bite from a lone star tick.
[24] A 2012 preliminary study found unexpectedly high rates of alpha-gal allergy in the western and north-central parts of the United States.
[6] Alpha gal is found on the fragment-antigen binding (Fab) fragment of the recombinant monoclonal cetuximab antibody used in the immunotherapy treatment of metastatic colon cancer.
Immediate hypersensitivities and reactions, specifically concentrated in the southern part of the United States, can be seen from the alpha-gal components of this anti-cancer drug.
[3] Anaphylactic transfusion reactions have been reported in patients with presumed alpha-gal syndrome who had type O blood and received group B plasma or platelets.
[29] Diagnosis begins with initial suspicion of alpha-gal syndrome following a thorough review of an individual's medical history and clinical symptoms.
[6][22][9] In addition to avoiding triggers, such as mammalian meat, treatment is aimed at alleviating symptoms and is highly dependent on severity.
If an allergic individual who only experiences relatively mild symptoms consumes food containing alpha-gal, then treatment with over-the-counter antihistamines may be acceptable.
Low-quality evidence favors mechanical techniques over chemical treatments such as gasoline, petroleum jelly, or clear fingernail polish.
[36] The allergy was first formally identified as originating from tick bites in the United States in 2002 by Thomas Platts-Mills,[37] and independently by Sheryl van Nunen in Australia in 2007.
[38][39][40] Platts-Mills, Tina Hatley Merritt, and Scott Commins were attempting to discover why some people were reacting negatively to the cancer drug cetuximab.
[6][9] They discovered that these individuals had IgE antibodies in their blood that were specifically targeted to the portion of cetuximab which contained the alpha-gal carbohydrate.
[21] Van Nunen, an immunologist specialising in allergies, had been practicing in a tick-prone area of Sydney, when 25 patients reported having allergic reactions to red meat after being bitten by ticks.
[51] For those undergoing surgery, possible triggering agents include porcine-derived heart valves, insulin, heparin, thrombin, and surgifoam powder.
[23] In 2023, a false conspiracy theory connecting alpha-gal syndrome to Gates Foundation tick research was spread on social media.
