WillDr4Beer

It does, subclasses of IgA determine your tolerance to a food. Everytime your body is in contact with something including your own cells it asks it: "mine or not mine", if it's mine the you get antibodies which prevent the body from attacking it (in the case of food, IgA has a big role in this, as it is one of the main antibodies in saliva. This is how tolerance is created, you're tolerant to all that which you're not allergic too, and the main endpoint of allergy treatments is creating tolerance). And depending on which type of not mine it is, it creates related antibodies or defense mechanism.

Ask your allergist/immunologist about it. I ask, cause I'm an allergy and immunology specialist, and people with multiple food allergies should have their IgA level checked.

Have you been tested for selective IgA deficiency? Or other sorts of immune deficiencies related to the production of antibodies?