Dr. Caroline Sokol Works to Unlock the Secrets of the Sensory Nervous System-Food Allergy Connection

A-ha moments can arrive in a multitude of ways. For Dr. Caroline Sokol, M.C., Ph.D., a Food Allergy Science Initiative (FASI)  researcher, hers manifested in the form of a bee sting.

The research that emerged from that moment – a sting on her then 3-year-old child’s hand – has since shed considerable light on the human neuroimmune response and the brain’s role in allergic symptoms like pain, itch and aversion to certain foods.

A New Perspective on Allergies

Dr. Sokol, an assistant professor of medicine at Harvard Medical School and a physician in the Allergy and Clinical Immunology Unit at Massachusetts General Hospital, had already spent more than a decade trying to understand how human immune cells were detecting the enzymes that had been determined to cause allergic reactions.

But after her child’s sting, she came to a startling conclusion. “As an allergist, I know that the venom in bees is really good at inducing an allergic immune response. And I realized when he got that sting, that poor kiddo immediately was in pain and itchy at the site,” she said. 

But those reactions were a result of the sensory nervous system being activated, not the immune system, she noted. “And that made me start thinking about the sensory nervous system playing a role in allergen detection because obviously that was the first thing that got activated there.”

A Spark of Inspiration

Back in the lab, she applied her suspicions to a mouse model of allergic immune responses, noting that when mice were exposed to the allergens, they seemed irritated at the exposure site. She then met with a fellow FASI investigator, Dr. Issac Chiu, and together they teamed up to see if allergies could be directly detected by the sensory nervous system.  

“And we found out that – oh my gosh, yeah – sensory nerves can directly get activated by allergens. They lead to itch responses,” she said. “And in the end, what we showed with help from Isaac’s lab was that no, it isn’t the immune system that’s the sensor of allergens, it’s the nervous system, which then relays that activation to the immune system.”

That discovery led to what Sokol called a “reckoning” in her lab, which turned its focus to those nervous system activations after detecting allergens. “We look at how the sensory nervous system and the immune system hook up to initiate allergic immune responses and how they regulate each other to cause more or less severe allergic immune responses,” she said.

“Understanding this pathway, researchers can now think about ways to target and block it to reduce the severity of or prevent food allergies,” she added. “That has led us now to actually look at some FDA-approved drugs that are already on the market, as well as new targets to see if we can potentially shut down this response.”

Bringing Knowledge into Practice

Outside of the lab, Sokol said her research continues to be informed by the experiences of patients in her allergy clinics, particularly when it comes to food allergy challenges. 

“At FASI I met a lot of researchers looking into food aversion and avoidance of food,” she said. “One thing I realized with my food allergy patients was how many of them actually would taste a little bit of peanut butter and just find it absolutely disgusting. And then realizing that this aversion is one of the biggest predictive factors that someone’s going to fail a food challenge.”

In addition, she better understands that many allergic diseases such as neurological-based inflammation – which includes things like asthma, irritable bowel disorders and chronic rhinitis – don’t have clear allergens associated with them. “So it’s really opened my eyes to the clear connection between the nervous and immune systems, and the potential clinical and pathological reasons for some of these diseases I see in my patients,” she said.

An Unexpected Path

Sokol admits that as she began her medical and scientific career, she was dubious about the study of allergies and type-2 immunity.

“I thought it was a dead area of science – that it was an area that was mostly pseudoscience, actually,” she said, laughing. But as an M.D. Ph.D. student, she joined the lab of Ruslan Medzhitov, Ph.D., FASI chief scientific officer, and was soon convinced otherwise. Medzhitov assigned her to investigate the basic mechanisms driving the type-2 immune response.

“I started doing it and absolutely fell in love with the field because we didn’t know anything … so getting into a field like type-2 immunity was like going into the wild west. There were no rules, no principles, there were no real mechanisms,” Sokol said. “Now, not only do I study type-2 immunity, but I’m a clinical allergist, too. So my whole career is in this area that I thought I would never get involved in.”

The Power of the FASI Model

That divergence from what Sokol thought would be her original career path is a happy result of the FASI funding model, which is focused on finding experts to contribute to research from their own areas of expertise toward the ultimate goal of finding a food allergy cure.

“What FASI does is they come in and take the approach of, ‘Let’s find the right people who are going to be thinking in innovative ways and let’s actually go for that moonshot,’” she said. “They promote different types of science. They allow people to have that freedom to really think outside the box and maybe fail, but maybe find something completely different in the failure that’s still going to be relevant for food allergy. That, I think, is the amazing part about FASI.”

FASI is the organization leading the way to the discovery of innovative therapeutic developments that could address the root cause of food allergies, and we’re proud to invest in scientists like Dr. Caroline Sokol. The only way we can advance her work, and that of our other investigators and discover potential treatments, is through your continued support