Hay fever relief could come in the form of a nasal ‘molecular shield’

People with hay fever could one day benefit from a first-of-its-kind “molecular shield” that blocks pollen from entering the lining of the nose, and is unlikely to cause the side effects seen with standard treatments.

Hay fever is an allergic reaction that occurs when pollen binds to molecules called IgE antibodies in the lining of the nose, mouth and eyes, triggering inflammation that results in symptoms such as sneezing and itchiness. Treatments include antihistamines and steroids, which dampen inflammation, but aren’t always effective and commonly have side effects, such as drowsiness.

To find an alternative, Kaissar Tabynov at the Kazakh National Agrarian Research University in Kazakhstan and his colleagues first collected blood samples from mice. They then extracted an antibody that isn’t involved in allergic reactions, but still binds to the main allergen in mugwort pollen, a major cause of hay fever. This binding then blocked the allergen from attaching to IgE antibodies in a lab dish. “It acts like a molecular shield,” says Tabynov.

To see if this reduces irritation, the researchers induced mugwort pollen allergies in 10 mice by injecting them with the allergen and a chemical that trained their immune systems to react to it.

A week later, they put a small droplet of liquid containing the pollen-blocking antibody into the noses of half the mice, doing so a total of three times over five days. The remaining animals were given droplets of saline solution instead. One hour after each droplet was administered, the mice were exposed to mugwort pollen at levels similar to those that people are exposed to during the plant’s peak hay fever season, says Tabynov.

After the final droplet, the mice given the preventive antibody rubbed their noses 12 times, on average, over 5 minutes, versus 92 times in the saline group.

The researchers expected that the antibody reduced inflammation, which they confirmed when imaging nose tissue samples collected from the mice at the end of the study. This also showed that the treatment had effects deeper within the body, not just where the droplets were applied. “Our study is the first to demonstrate that an allergen-specific monoclonal antibody can be applied intranasally to achieve both local and systemic protection in the context of plant pollen allergies,” says Tabynov.

Although the researchers didn’t measure potential side effects, they don’t expect the approach to cause the adverse events seen with oral hay fever drugs, because it works at the site of allergen entry.

“This study is an important milestone, highlighting the potential of intranasal therapies for allergic rhinitis [hay fever] and helps pave the way for early clinical trials investigating the potential of this approach in humans,” says Sayantani Sindher at Stanford University in California.

But success in mice may not translate to efficacy in people and the antibody will need to be adapted to work in humans to ensure it doesn’t provoke its own immune reaction, says Tabynov. If all goes smoothly, the team hopes to trial the approach as a nasal spray in people within the next two to three years, he says.

Such sprays may also work against other types of pollen that cause hay fever. “We envision a future in which customised antibody sprays could be available for people allergic to different types of pollens,” says Tabynov.

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