Newly Discovered Cell Could Be The Reason We Don't All Have Allergies

Allergies occur because our immune system gets paranoid, becoming convinced harmless things are out to hurt us. It responds by producing Immunoglobulin E (IgE), which creates a reaction that "manifests itself from mild localized symptoms like a runny nose during hay fever season, to very aggressive systemic inflammation like anaphylaxis," Australian National University PhD student Pablo F Canete explained in a statement.

After the discovery that mice have a cell that modulates IgE production, Canete went looking for something similar in humans. He suspected it might be concentrated in the tonsils, because, he told IFLScience, “Sitting at the back of the throat, they are exposed to all sorts of molecules from food and air an over-active immune system might see as dangerous.” Using tissue donated by 200 children who had undergone tonsillectomies Canete went looking.

The search turned out to be more difficult than Canete expected. He told IFLScience: “The human cell looks quite different from the mouse counterpart, it doesn't have the master gene regulator that exists in mice.” Nevertheless, Canete has now described the discovery of a subset of tonsillar follicular T cells that suppress IgE production in the Journal of Experimental Medicine. 

Among the tonsils studied, the higher the concentration of these cells, the lower the IgE, and the less likely the children were to suffer from allergies.

Canete hopes the discovery will lead to replacements of antihistamines in allergy control. He told IFLScience this is likely to be through identifying the molecules the cells produce and replicating them. “That's likely to be easier than boosting cell production.” However, he stresses there is much work to be done before that day, starting with the search to find the cells elsewhere in the body. “If we can find them in blood it will make our job much easier,” Canete noted, given the obstacles to accessing tonsil samples.

Canete also hopes to learn more about the range of allergies for which these cells are relevant, rather than lumping all responses together as he has done so far.

IgE is needed against genuine threats, and Canete acknowledges any attempt to reduce production must take this into account. However, he says it is thought allergic responses occur because the immune system mistakes allergens like pollen or peanuts for parasites or venom. These are diminishing threats in the developed world, while allergy rates are climbing thanks to climate change and junk food.