Allergy is a hypersensitive immune response or unwanted reaction created by our body on encountering any foreign substance, toxic or hazardous compound. Allergic response created within the body due to ingestion of any toxic substance, fumes, gas, vapor, radioactive substance or food substance destroyed by micro-organism produces varying symptoms like redness, itching, cramps, lesions, ulcers, sneezing, watery eyes, runny discharge from nose, headaches, swelling and inflammation of body parts.

Our body via host defense mechanism generates primary and secondary allergic response by release of chemical compounds in form of antigens and antibodies. Industrial occupations emit heavy doses of allergic compounds like dust, mites, pollens, detergents, fumes, chemicals, mist, bacteria and virus from organic wastes, air, water, food or earth and cosmic radiations. Body susceptible to chronic allergies multiplies into severe illness and other common diseases (acute allergies) can turn fatal for an ignorant human being.

Development of allergic disease has been associated with heredity and various environmental & health factors as already described. Allergens cause release of histamines into the body. Histamine is a vasodepressor amine derived from enzymatic reaction of histidine rich compounds present in smooth muscles and bronchioles, which cause dilation of blood vessels and capillaries. Histidine is abundantly present in animal tissues and ergot, which induces release of histamine from basophils of WBCs causing vasodilation, spasms and erythema.

Antihistamines generally used to counteract allergens in early stages suppress immune system by releasing specific IgE antibodies, which attach to basophils of WBC or mast cells that line intestine and mucosal membranes. Specific IgE antibodies that appear in human serum or plasma because of sensitization to a specific allergen can be detected following exposure. The development of allergic symptoms is a result of complex interactions between various allergens, allergen specific IgE antibodies and other parts of the immune system that culminate to influence a response in the various target organs. Symptoms of allergy vary in complexity, severity and organ manifestation.

Table 1 describes the loading concentration of any allergen and clinical significance of appearance of IgE antibodies. Results indicated in Table 1 are following specific Immuno CAP IgE antibody test (in-vitro) which measure the concentration of circulating antibodies in human serum or plasma. The objective of this clinical test to predict the level of sensitization for diagnosing risk of allergic mediated disorders and guidance of clinical decisions.

Allergy is a cumulative threshold disease which means allergy may remain asymptomatic until exposure to additional allergens accumulate to produce a combined allergic load detected as Class II or Class III allergic load. Once this cumulative load crosses a certain threshold, it leads to symptomatic disease in such polysensitized patients. In monosensitized patients, allergic symptoms occur only after sufficient exposure to that one allergen. Patients can find resolution of their symptoms through the avoidance of one or more allergens in order to diminish the cumulative load to a level at which symptoms don’t occur. Clinically equivalent manifestations occur for monosensitized and polysensitized patients with particular IgE antibody concentration detected in their serum or plasma. Cross reactivity between various allergens have been documented, for example, latex specific IgE with ragweed and certain food allergens such as banana, avocado, kiwi and chestnut. A definitive clinical diagnosis should not account on the results of any single diagnostic in-vitro method rather based on physician’s experience after all clinical and laboratory findings is evaluated.

What is food to one man may be fierce poison to another. Food poisoning is an allergic reaction to food that may cause unpleasant symptoms and is associated with a host of chronic disease conditions. Food poisoning is unlikely to be life threatening, unlike autoimmune diseases caused by other allergies. While less than two per cent of Indian population suffer from food allergies, it is estimated that more than 20 per cent of population suffer from food intolerance. However, no statistical relation has been derived between the population suffering from food intolerance, which develop food allergy or severe food poisoning at some point later in their life.

Food poisoning can affect anyone at any age, but since symptoms often occur sometime after consuming the food, it can be difficult to find out the problem food without the use of advanced laboratory testing. For example, the milk or bread eaten one day could be the cause of joint pain three days later. This depends upon the lifestyle and eating habits of an individual as well as age.

Micro-organisms and enzymes present in our digestive tract help breakdown of complex organic molecules into simpler substances. Polysaccharides and carbohydrates get converted into dextrin and glucose, Proteins into constituent amino acids and Fats into triglycerides by digestive enzymes. These micronutrients are then absorbed into our bloodstream and transported to various cells and tissues. Majority of allergic reactions produced through an organic food substance result from altered activity of gastric bacteria and enzymes. Some food intolerances result from enzyme deficiency or chemical sensitivity, while others mediate through immune response.

Lactose intolerance is a common food allergy mediated through immune response in infants and adults because cells develop resistance to Lactobacillus spp. or lactose to derive energy and carry out metabolism. With the onset of a food allergy, person may develop intolerance to particular food substances and experience withdrawal symptoms. Lactose intolerance in an individual will tend to develop food intolerance for dairy products like milk, cheese, cottage cheese, butter and yogurt. Antibody levels significantly reduce during food intolerance and it is highly unlikely that food test will be able to detect IgE antibody for such foods. Re-introduction of food earlier withdrawn from the diet may produce a host of allergic reactions depending upon the extent of food intolerance and time-period for which was withdrawn from the diet. Food poisoning is associated with host of conditions involving both immunologic and non-immunologic functions like mal absorption, vomiting, constipation, diarrhea, fatigue, gastritis, and arthritis.

Majority of food intolerances are a result of an immune response to foods that developed because of poor diet, poor digestion, parasites, intestinal infections, alcohol consumption, effects of drugs and medications, which cause depletion in enzyme concentration responsible for digestion of particular organic food compound. A feedback cascade of enzymes and signaling molecules regulates our body metabolism and small changes to amount of food substrate or enzyme bring drastic effects in metabolism of a particular food substance.

Each individual has a unique reaction to food. Production of antibodies is one of the ways in which the body's immune system reacts to substances that adversely affect it. Over time, the antibodies form immune complexes, which deposit in joints and other organs, and may be responsible for many symptoms seen in food poisoning. Gastrointestinal (GI) allergy is more common than other allergic disorders, especially in early childhood. Symptoms in GI allergy closely associated food intolerance to produce abdominal pain, and regurgitation.

In food allergy, circulating IgE antibodies may remain undetectable despite a convincing clinical history, as antibodies either directs towards allergens that reveal themselves or alter by digestion or immune response created within our body. For penicillin specific IgE determinations, a result obtained above limit of quantization indicates the presence of specific IgE antibodies to penicilloyl, the major determinant of therapeutic penicillin. Drug specific IgE determinations results below limit of quantization indicate the absence of specific IgE antibodies to the specific drug and loss of immune function because of non-sensitivity. Patients hypersensitive to drugs produce symptoms mediated without involvement of IgE antibodies. Similarly, high doses of steroids or use of immunosuppressants following an organ transplant affects production of IgE antibodies. Ideal conditions for blood testing of allergic load is from two to three weeks after exposure to the allergen and not later than six months.

Nutrition experts and dieticians have devised IgG antibody testing for food intolerant substances that bypass immune function like amine in chocolates, tryamine in red wine and cheese, taatrazine and monosodium glutamate type food additives, which produce symptoms like migraine, hives, rashes, shortness of breath and joint pain. While IgE antibodies appear in an instant for most allergies of skin, sensory organs and respiratory tract; IgG antibodies involve central nervous system (CNS) and autonomous conditions involving adrenaline and nor-adrenaline. Undigested or partly digested food materials on passing through digestive tract of people with chronic diseases develop a “leaky gut syndrome”.

Inflammatory mucous membranes lining the intestinal tract respond by producing a large amount of IgG antibodies. However, this test is still not been approved clinically for confirmed diagnosis of symptoms associated with Food poisoning. Experts say that IgG antibodies remain detectable for a long period even after withdrawal of a particular food substance from one’s diet. IgG antibodies produce antigen-antibody complex by combining with the protein in the food. If immune system is compromised these complexes bypass cell membrane to deposit in various parts of the body such as head, lungs, gastrointestinal tract, bones and joints to produce symptoms like headache, migraine, eczema, skin rashes, asthma, arthritis and irritable bowel syndrome. Religare SRL diagnostics has developed a highly sensitive protein microarray technology for testing IgG antibodies from more than 200 different types of food substances.

Human body has a complex and well-developed defense mechanism, which fight against many foreign compounds and substances while entering into body or upon entry in the body. Human Immune system has well-developed mechanism to resist foreign pathogens, allergens and toxic compounds by generating appropriate immune response. Blood is the most essential cellular entity that distributes nutrients and oxygen throughout the body and part of blood called White blood cells (WBC) protects other cells of internal organs from bacteria, virus, fungus and other similar pathogens.

Internal or external injury or wound leads to formation of blood clot to generate appropriate immune response during allergic diseases or food poisoning. People who have less developed immune system suffer from severe combined immunodeficiency syndrome (SCID) and exhibit a host of allergic reactions on their body towards various food substances. Autoimmune disorders are the major cause for rising cancer diseases in our society and compromised immunodeficiency for large number of pre-mature deaths. Immunity is an important parameter for health evaluation and it is equally important for people working in industrial occupations to understand source of hazards to minimize dosage intake.u