|The Allergy Center|
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Immune Mediated Diseases
The original concept of allergy included all immune-mediated disease and the term allergy was interchangeable with the term "hypersensitivity."
One textbook of clinical immunology defined allergy: “The original definition of allergy in 1906 was --- a specifically changed reactivity of the host to an agent on the second or subsequent occasions. This covers a whole spectrum of immune responses, both protective and harmful. However, more recently, the term allergy had been restricted to type 1 hypersensitivity. This rigid definition is too narrow to cover the range of conditions seen by allergists in clinical practice. It is likely that all four types of hypersensitivity are involved in various allergic diseases and indistinguishable reactions can sometimes be produced without immunological involvement."
Delayed patterns of allergy are not obvious and generally go unrecognized. Allergy skin tests do not show this problem. Symptom onset is delayed hours to days after exposure to the trigger foods. Allergic reactions to drugs such as penicillin and to foods are usually delayed hypersensitivity.
Many chronic diseases are either degenerative and/or inflammatory and many are recognized to be immune-mediated or hypersensitivity diseases. The delayed patterns of allergy can be the cause of chronic and disabling hypersensitivity disease. The stakes are high both for individual patients and for the society as a whole. None of the common hypersensitivity diseases have been solved and most appear to rage on, afflicting increasing numbers of patients with disabling diseases. Asthma, allergy, rheumatic diseases, autoimmune diseases, multiple sclerosis, diabetes, thyroiditis, psoriasis are examples of hypersensitivity diseases which involve humoral and cell-mediated immunity. We use celiac disease - wheat allergy- as a prototype which demonstrates the prolific ability of food allergy to produce a wide range of diseases.
Prominent allergist-immunologists such as Brennerman, Gerrard, Knicker, Hill, Brostoff and numerous others for many years made conspicuous efforts to elucidate the delayed forms of food allergy which involve the most profound immune mechanisms. Unfortunately, all the good science that has been done is now mostly ignored. Allergists for the most part act as if delayed patterns of food allergy do not exist and physicians in other specialties have no idea about food-related immune mediated disease. The only hope for patients is to resolve these problems is to take charge of their own management.
Four mechanisms of immune activity
When trying to understand the wide spectrum of hypersensitivity disorder, it is help to return to the Gell Coombs concept of 4 immune mechanisms:
Type 1 or immediate hypersensitivity is IgE-mediated or common allergy.
Type 2 or cytotoxic reactions mediated by antibody, complement, and/or cellular mechanisms. The target in type II reactions is a cell membrane and cellular damage or death is the result.
Type 3 mechanisms involve antibodies forming immune complexes with antigen. Circulating complexes activate complement, attach to red blood cells that are removed by phagocytosis in the spleen, or leave the circulation and trigger inflammation in tissue spaces (Arthus reaction), or are phagocytosed by macrophages in tissue spaces which present antigen, release cytokines and activate T-cells.
Type 4 are cell-mediated reactions take 12 or more hours to develop and are based on antigen, T-cell interaction. Inflammation is the basic tissue pattern.
Allergy can be thought of as hypersensitivity disorders with external causes. Substances that trigger allergic responses are antigens. These are often proteins that can be found in air, food and water. Airborne antigens such as plant pollens or house dust are well known. Other airborne antigens and food antigens are less obvious. Airborne fungi trigger delayed hypersensitivity diseases in the lung. New and foreign substances introduced to the body such as drugs and herbs usually cause delayed allergic reactions.
When considering the origin of hypersensitivity diseases, food materials should be given priority consideration since that are the biggest chunk of the environment to get inside human bodies. If the term "food allergy" refers to all interactions between molecules derived from the food supply and the immune system, then many hypersensitivity disorders fall into the category of food allergy.
Prototype of Type III -IV Illness Systemic Lupus Erythematosis (SLE) is an immune-mediated disease which serves as a model of hypersensitivity disease. The peak incidence of SLE is in women between the ages of 20 and 40 and who present with a typical malar rash, lymphadenopathy, arthralgias, fever, fatigue and will often complain of recurrent flu-like illness. As the disease advances, increased evidence of target organ damage can be found with protein and red cells in the urine, pleurisy, pericarditis, hair loss, and circulating auto-antibodies, especially antinuclear.
Listen to Delayed Allergy as Hypersensitivity Diseases
Learn More About Delayed Hypersensitivity