A vaccine for food allergies?

No less than 6% of the UK adult population has a clinically confirmed food allergy. Now, momentum is gaining on fine-tuning a vaccine that could offer year-long protection against allergic attacks.

A severe, potentially life-threatening allergic reaction (anaphylaxis) to foods such as shellfish or peanuts, as well as some medications and insect venom, constantly hangs over hundreds of millions of people worldwide. The condition causes the immune system to release a flood of chemicals that can cause a person to go into shock, with blood pressure dropping suddenly and the airways narrowing to block breathing. Symptoms also include a rapid, weak pulse and a skin rash, nausea and vomiting. Even kissing someone who has recently eaten a food to which you are allergic can set this unwanted train in motion, with a spike in immunoglobulin E (IgE) antibody molecule production by the immune system.

Aside from trying to avoid the allergen, the options for preventing such attacks are limited. Oral immunotherapy involving gradually increasing intake of an allergenic food under supervisions to build tolerance is one. Another is to take a drug called an anti-IgE such as omalizumab, but this is expensive and needs to be injected every several weeks, potentially for life.

But now, a vaccine has been developed at the Toulouse Institute for Infectious and Inflammatory Diseases, France, sporting the name IgE-K. It conditions the immune system to produce antibodies that target IgE to stop it from binding to receptors on immune cells, thus halting an ensuing runaway allergic reaction. They wanted to come up with a long-term solution, because as a food-allergic person you can also be exposed by accident at any time.

Tests on mice that had been modified to produce a human version of IgE showed researchers that two doses of the vaccine induced the mice to generate neutralising antibodies against IgE, hence blocking the molecule that makes one allergic. Unvaccinated mice subsequently given a substance to cause an allergic response displayed a strong reaction, while vaccinated ones were protected against anaphylaxis for as long as a year without adverse effects. This period could be longer, but more protracted testing will be required to confirm this. As part of the body’s immune system IgE also responds to some intestinal parasites and venoms. Many people have been given anti-IgE therapies for years on end without ill effect. A further test found that the vaccine did not impair the immune response to infection by a parasitic nematode worm Strongyloides ratti.

While clinical trials are still needed to demonstrate the safety, efficacy and duration in humans, it is known that the mice created the same antibody binding the human IgE molecule so the chances of a successful outcome are deemed high.

Of the smorgasbord of activities under way in the field of vaccine research, not a few believe this to be among the most important, as so many people have to be mindful of what they place in their piehole with potential (unexpected) consequences ranging from the merely unpleasant to the very shuffling off the mortal coil.