Scientists at McMaster University in Canada and at Mount Sanai in the US have co-discovered the cells that remember an allergy.  The Canadians call it MBC2 while the Americans call it a type 2 Memory B cell.   

B cell refers to a type of lymphocyte critical to immune function.  B cells are the factory for producing immune proteins called immunoglobulins (Ig’s).  Ig’s have a finite life span, but the B cells are much longer lived.  This is important in terms of providing for long-term immunity.  It’s our memory B cells that keep producing Ig’s (AKA antibodies) for all the illnesses we have caught and for all the vaccines we have received.  IgG is especially important in its role of providing durable immunity.   

IgE is the immune protein that causes allergy.  When B cells switch from making IgG (the protective antibody) to making IgE (the allergic antibody) it’s called an isotype switch.  You might ask why in the world would our B cells change from helping to harming?  As it turns out, other than causing allergy, IgE attacks parasites.  Our distant human ancestors all had one or another parasite in their GI tracts.  So, we evolved as a species to have a protective mechanism for this problem.  Fast forward to proper sanitation, safe drinking water and universal footwear and the worms are gone.  So now the IgE is segued to causing allergy.   

Although many people find that their allergies improve over time, many do not.  Peanut allergy is particularly known to be a persistent allergy.  So, the researchers used peanut allergic individuals to find these new memory B cells that weren’t found in non-allergic people.   

It is known that RNA (ribonucleic acid) instructs the B cells to switch from IgG production to IgE.  It does this through a protein called JAK (Janus Kinase).  So, new research is targeting this JAK signaling to see if the long-term memory can be switched off.