Scientists at the National Institutes of Health have discovered a potential treatment for alpha-gal syndrome, a potentially deadly tick-borne condition that leaves sufferers unable to eat red meat.
In a laboratory study, researchers found that man-made antibodies can bind to the parts of the immune system that trigger the severe allergic reaction. This mechanism may stop the allergy from occurring entirely.
Alpha-gal syndrome is an allergic reaction to alpha-gal, a molecule present in the cells of cows, pigs, and other mammals, but completely absent in humans. The condition is caused by the bite of a tick carrying the molecule in its saliva.
When the tick bites a human, it transfers the alpha-gal molecule. The bite prompts the human immune system, the complex network of biological processes that protects the body from disease, to attack the alpha-gal molecule as if it were a dangerous infection. This immune system response is what causes the allergy.
"Tick bite-associated cases of AGS are increasing in the US and globally, and there is currently no specific treatment or prevention for it," said Dr John Powers, a director at the National Institutes of Health, the primary agency of the United States government responsible for biomedical and public health research.
"This is a first step in potentially identifying ways to prevent [the condition] and develop new targeted therapies for people before they are affected," Dr Powers said.
Symptoms and dietary restrictions
Individuals suffering from alpha-gal syndrome who consume products such as beef, pork, lamb, venison, and gelatin may experience hives, nausea, and severe stomach pain. In serious cases, the allergy can trigger anaphylaxis.
Anaphylaxis is a rapid, severe, and potentially life-threatening allergic reaction that can occur within minutes of exposure to an allergen. If not treated immediately, it can restrict breathing and cause a dangerous drop in blood pressure. Some individuals with alpha-gal syndrome may also experience reactions to dairy products.
To avoid a reaction entirely, sufferers are advised not to consume beef, pork, lamb, or organ meats such as kidneys, livers, and intestines. They must also avoid gelatins and gelatin-coated medicines. Patients are strongly urged to check the ingredients list for stock cubes, gravy packages, and flavored ingredients before consuming them.
There is no specific treatment or cure for the condition at present. The only way to prevent it is to avoid tick bites and to stay away from trigger foods if diagnosed. For mild allergic reactions, doctors may use standard allergy medicines to manage the condition.
According to the Mayo Clinic, an American academic medical center focused on integrated health care, many people with the allergy carry an epinephrine auto injector. This device delivers a measured dose of adrenaline that can be used to instantly calm the immune system and reverse the severe symptoms during a reaction.
The lone star tick
Anyone bitten by any tick could develop alpha-gal syndrome, but the lone star tick is most likely to cause the disease. This species of tick is easily identified by a distinctive white spot on its back.
Lone star ticks are most common in the Northeast, Midwest, and South of the United States. Their population has exploded in recent years, a trend that has been linked to the rising deer population across these regions. Furthermore, warming global temperatures are allowing the insects to survive longer and advance further inland.
The Centers for Disease Control and Prevention, the national public health agency of the United States, estimates that there are nearly 450,000 cases of alpha-gal syndrome nationwide. Overall, approximately 31 million people are bitten by ticks annually in the country.
Researchers at Virginia Commonwealth University, a public research university in Richmond, Virginia, noted a 100-fold increase in positive tests for the disease between 2013 and 2024. However, experts state that some of this increase may be due to growing public and medical awareness of the disease rather than an actual rise in case numbers.
Accidental discovery during malaria research
The breakthrough at the National Institutes of Health happened while researchers were initially investigating whether alpha-gal-fighting antibodies could be used against malaria. Antibodies are proteins produced by the body to detect and neutralize harmful substances. Man-made versions, often called monoclonal antibodies, are laboratory-produced proteins engineered to serve as substitute antibodies.
Malaria is a serious and sometimes fatal disease spread by mosquitoes. Because the disease also contains the alpha-gal molecule, the researchers wanted to learn whether the man-made antibodies could help to prevent a malaria infection from taking hold.
In their published paper, the scientists noted that they exposed 42 alpha-gal-targeting antibodies to malaria. They found that none of the antibodies bound well to the mosquito-borne disease.
When they realized the alpha-gal fighting antibodies had no impact on malaria, the scientists shifted their focus. They decided to investigate whether these man-made proteins could impact the specific antibodies that cause alpha-gal syndrome instead.
Potential for future treatments
The researchers found that 13 of the man-made antibodies could bind to the antibodies that cause alpha-gal syndrome. Furthermore, one of the antibodies was also able to bind to an immune system cell that triggers the allergy. The scientists said this specific interaction might help to reduce the allergic response effectively.
The scientists noted that other allergies, including those to pollen, peanuts, and cats, can already be treated using man-made antibodies. They stated that this precedent suggested the same approach might also be able to help treat alpha-gal syndrome.
The research is still in its very early stages, but the scientists hope it will help them develop a potential treatment for the condition. It is not clear whether this approach could completely cure the condition, but it may be able to prevent an allergic reaction if a sufferer consumes red meat.
"We are thrilled that this research is helping to advance the development of alpha-gal-specific... antibodies as a potential intervention for AGS," said Dr Peter Crompton, a senior investigator and the lead author of the study.
"This discovery is also a remarkable example of how collaborative global health research can lead to breakthroughs that improve the health and well-being of Americans," Dr Crompton added.
