Mechanisms Of Allergy and Intolerance

It’s all about the details. Pick your thumbnail image, add closed captions, update settings, and track your video performance analytics in the video library. Manage video settings. Learn more about the video library.

Introduction to Hypersensitivity (“Classic Allergy”)

Hypersensitivity Hypersensitivity (a heightened state of extreme sensitivity) is another word you will hear applied to allergy. There are four distinct types of hypersensitivity: Types I to IV. These divisions are useful for discussion but may not necessarily occur as single entities in an individual.

Type I Hypersensitivity

Type I reactions are basically antigen-antibody reactions. This is what is usually meant by a classic allergic reaction. Mast cells release chemical mediators such as histamine, bradykinin, anaphylotxin, slow-reacting substance-S and others. This gives rise to severe local inflammation, which may cause bronchospasm (asthma), sneezing (rhinitis), urticaria (or other skin rashes) or diarrhoea and vomiting if the gut is the target organ. The occurrence of Type I reactions to foods is undisputed. Typical offenders are milk, eggs, fish and nuts, though any food can do it. Reactions normally occur shortly after food ingestion and are usually associated with positive skin prick tests and generally a positive radio allergosorbent test (RAST) to the relevant food (see conventional allergy tests). Type I reactions are more common in children and have a tendency to disappear as the patient gets older. Reactions to insect bites and stings are Type I in nature and can be fatal, if severe, though this is rare.

Type II Hypersensitivity (Cytotoxic)

This type of reaction occurs when an antibody is directed against a cell-surface or tissue antigen. Complement activation leads to the generation of inflammatory mediators, with resulting tissue damage. Cytotoxic tests probably rely on this process. Diseases caused by Type II hypersensitivity include certain haemolytic (cell-destroying) anaemias, purpura (bruising) and systemic lupus erythematosus; it is also usually to blame in incompatible blood transfusions. The infamous Minamata disease (mercury poisoning) was of this type. Diagnosis is done by detecting serum antibodies. Raised levels of circulating serum anti-bodies are seen in many cases of bowel disorder thought to be due to food sensitivities but, unfortunately, they are also seen in healthy individuals and their role in food allergy seems confusing and unclear.

Type III Hypersensitivity

Type III reactions result from the deposition of antigen/antibody complexes in the tissues. These complexes are commonly produced after eating, and indeed would be expected. Normally they are removed by the reticulo-endothelial system. But if the formation of immune complexes is excessive, the quality of the complex is abnormal or the reticulo-endothelial function is impaired, then this normal process is unworkable and disease results. Tissue damage occurs as a result of the inflammation surrounding these abnormal deposits. Rheumatoid arthritis is an example deposits. Rheumatoid arthritis is an example of a Type III process, systemic lupus another. These are all types of auto-immune (self-damaging) diseases.

Type IV Hypersensitivity

This is often called the delayed hyper-sensitivity reaction, so-named because of the fact that in skin testing the reaction may not show up for 12 to 48 hours. Antibodies are not involved. Contact dermatitis is one clinical condition caused by this process. Conventional allergists say this reaction has little to do with food allergy. Clinical ecologists disagree: it quite commonly causes food allergy. Many patients react late after challenge testing. The reason the patients’ reactions are considered irrelevant is that most doctors do not see them (the patients have gone home) and, since some doctors are not in the habit of listening to information from their patients, they miss it!

Enzyme Deficiency

Finally, there is the phenomenon of enzyme deficiency, often called ‘inborn errors of metabolism’. Some people are made ill by their inability to detoxify or metabolize foods, chemicals and drugs. An example is lactase deficiency, which causes people to suffer unpleasant abdominal symptoms when they drink milk. Children with phenylketonuria lack the enzyme phenylalanine hydroxylase and are unable to dispose of phenylalanine, which thus accumulates and causes mental retardation and neurological damage.

But deficiencies are not confined to such named disease conditions. There are thousands of enzymes in our bodies, all working in concert. Many of them are dependent on vitamin and mineral “co-factors” to function properly (for example alcohol dehydrogenase, the enzyme which breaks down alcohol, needs zinc and vitamin B1 to work efficiently).

Considering possible variations in inherited endowment of enzymes, complicated by missing nutrient factors, the reader will be readily aware that enzyme deficiency can be a very individual thing. This subject of innate biological variation is something which confuses the picture with respect to allergy and overload. Doctors will insist on foolishly believing that everyone is the same, we are all “average”. In fact only a tiny percent of the population is “average”, no matter what criterion you are measuring, the vast majority are all over the place, some very far indeed from that average figure (taken to its full absurdity this would be like saying the average height for a man in 5 feet 10 inches, therefore people who are under 5 feet or over 6 feet 4 inches simply don’t exist! Can you imagine tailors being as crazy as doctors are in this regard?).

The Chemical Victim In time it became obvious that some individuals were sensitive to environmental chemicals. It is hard to describe this as an allergy; probably the term ‘low-grade poisoning’ would be better since many of these chemicals would make anyone exposed to them in sufficient concentration feel ill. The problem is just that certain individuals react to smaller doses. We are all subject to a barrage of alien chemicals in our bodies (Greek word: xenobiotics, meaning alien to life. We have chemical pathways in our bodies designed to remove toxic substances: a process called detoxication or biotransformation. The trouble is these new man-made chemicals have no equivalent in nature and so we do not have the right systems in our body to fully eliminate the toxicity. In fact, in its attempts to deal with the problem the body sometimes, by mistake, actually coverts these xenobiotics into something even more toxic (Casarett and Doull’s Toxicology. Basic Science of Poisons. Third Edition, Editors: Klaasen CD, Amdur MO, Doull J, Macmillan, New York 1986).

Pharmacological (Drug-Type) Effects

Confusion can arise from the fact that there may be pharmacological effects masquerading as an ‘allergy’. For example, the headache, flushing, racing pulse and giddiness that can come on after too much caffeine is really a drug reaction, not an allergic one. Obviously individual variations in trigger thresholds make this one sometimes hard to observe.

Few people understand the incredible range of pharmacological substances that are to be found in plant substances. Most “green-minded” people think of herbs as kind, nurturing and gentle: wouldn’t hurt anyone, right? But, hey, I like to point out that foxglove, hemlock, opium poppy, marijuana, deadly nightshade and countless plants stuffs are dangerous, even poisonous. “Beware the humble carrot” wrote Richard Mackarness; this innocuous looking vegetable contains a neurotoxin. Not relevant? I had a patient in the 1980s, a young boy, who had epileptic fits every time he ate carrots or anything from the same food family: parsnip, celery, parsley, dill, fennel, coriander etc.

There is no doubt that in the right hands, plants have healing power, but they can also do great harm. Don’t confuse this type of reaction with a true allergy or even intolerance.

Information and Field Mechanism

Finally, we come to the newest and, if such a thing is possible, most outrageous and contentious theory of allergy and intolerance. That is not to say that it is unscientific, far from it; this model carries the merit of the very latest scientific understanding. That’s the problem: it is so far advanced that doctors still working in the stone age and unable to grasp the majority of mechanisms described above will have trouble coming to terms with this one.

We now believe that at least some activity we call allergy or intolerance comes, not from the physical substance, but its characteristic coded molecular “signature”. To explain this, let me start by introducing a simple observation – startling, maybe – but quite simple. I have observed it many times, so have other alert open-minded physicians: occasionally a patient may become sick, simply being near or in the presence of their key allergen. This means they did not swallow it, breathe it or touch it in any way whatsoever. It does not mean the patient is neurotic and “afraid of their allergen” or reacting through a Pavlovian conditioned response; it happens even if the patient is unaware of being in the presence of their allergen.

That’s odd. It must mean that the substance is transmitting some kind of signal. If so there would be an energy field and modern physics thinks a lot about fields and their properties. All fields are infinite in size; they may become very faint but if the tomato you are allergic to has a field, it extends to the ends of the universe! This field effect would explain another frequent observation of the allergy doctor, especially those engaged in skin or challenge testing: sometimes the patient will get sick INSTANTLY before any of the substance can have diffused or been transported to the body tissues.

And here is where the up-to-the-minute science comes in, thanks to Professor Jacques Benveniste, the man who set the scientific world alight by showing that diluting a substance even beyond the point where even a single molecule is left, does not stop it having a biological effect (predictably, he was attacked as a fraud since “it couldn’t be true” and therefore he must have cheated in some way. Davenas E, Benveniste J et al. ‘Human basophil degranulation triggered by very dilute antiserum against IgE’, NATURE, 1988, 333: 816-818). Fortunately, several other laboratories have since confirmed what he found (Effects of embryonic bursectomy and in ovo administration of highly diluted bursin on adrenocorticotropic and immune response to chickens. International Journal of Immunotherapy (IX:169-180) 1993, B.J. Youbicier-Simo, F. Boudard, M. Mekaouche, M. Bastide, J.D. Baylé). But by then Benveniste had been hounded out of his top scientific job.

What Benveniste had shown is that the traditional model of biochemistry is flawed. If it doesn’t need the presence of the substance to have an effect, it means the idea of molecule reacting with molecule or the lock-and-key model for “receptor sites” was not strictly correct. Since all of molecular biology is based on these supposed truths and molecular biology at the moment is regarded as the (only) path to the holy grail of understanding nature, it is easy to see why Benveniste was howled out of office. But his turn of fortune may have been lucky for science. He went on to investigate the electromagnetic properties of substances and discovered that each chemical had a unique identifying “signature” that could be copied through a transducer and recorded on a computer hard disc. This may sound weird but to prove his point, Benveniste sent the chemical signals around the world on the Internet, to different laboratories, including top universities. When copied and decoded at the other end, the “digitized” substance had exactly the same effect as the parent substance, though none was present.