The immune system is incredibly important, thanks to its role in fighting off dangerous invaders in our bodies. But sometimes it gets it wrong, targeting harmless proteins from things like nuts or dairy products and triggering allergic reactions that ironically can themselves be fatal. Now, researchers from Michigan State University have identified a mechanism that helps keep the immune system in check, potentially paving the way for drugs that could prevent allergic reactions before they start.

Currently, our best methods for dealing with allergies are just to avoid triggering substances, or failing that, using an EpiPen to lessen the reaction. But possible future treatments could include probiotics that keep allergens from getting into the bloodstream, skin patches that slowly desensitize the immune system to the offending proteins, nasal sprays that act like allergy vaccines, or even gene therapy injections that "turn off" the allergic response.

The new method identified by the Michigan State team could join that list. The researchers found what they call a control mechanism that can regulate the immune system's reaction to a foreign substance.

Mast cells are a type of immune cell that release chemicals like histamines in response to stressful conditions such as invading proteins, viruses or bacteria. The problem is that sometimes this goes into overdrive, releasing far too much and triggering the severe reaction. The new study found that this process is regulated by a cell receptor known as corticotropin-releasing factor 2 (CRF2).

"What we found is that the CRF2 receptor can act as an inhibitor, or a control point, in mast cells, which prevents them from becoming over-activated," says Adam Moeser, lead author of the study. "Up until now, no one has really understood the exact role this particular receptor plays on these important cells."

To test the function of the CRF2 receptor, the team isolated mast cells from mice, pigs and humans and blocked its function using drugs. Doing so increased the amounts of histamine released. That suggests that developing drugs that can do the opposite – ramp up the function of CRF2 – could be an effective way to regulate histamine levels and prevent allergic reactions.

"There's still more we want to know, like what factors – whether a person's sex or different types of stress – are involved in how this particular receptor works," says Moeser. "But now that we know the critical role it plays, a pharmaceutical company could potentially develop a drug that targets these specific cells. That would be the ultimate goal."

The research was published in the Journal of Allergy and Clinical Immunology.