<<Disclaimer: Verify this information before applying it to your situation.>> According to " The Immune System and How it Works "( a NIH publication) Allergies are mediated by Mast cells which are not a blood cells. They are found in the lungs, skin, tongue, and the linings of the nose and intestinal tract where they are resonsible for the symptoms of allergy. There is a counterpart to mast cells in the blood system which is called a basophil. Both mast cells and basophils work by degranulating and spraying their contents on what the body sees as harmful. Other parts of the allergy response sound similar to the immune response in general and it is mediated in part by B cells and antibodies, (IgE) but only the allergy response involves mast cells. Just trying to keep my own head clear on the distinction. Irma