Getting to know

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Immediate Hypersensitivity or IgE Allergy: an exaggerated defense mechanism reaction of  the body against an allergen, a few minutes following contact with it. It is responsible for  diseases and lesions such as urticaria, asthma, "angioedema" or anaphylactic shock.

Immune Cells: cells of the body which are dedicated to fighting pathogens. They are divided  into several categories:  B and T lymphocytes, macrophages, polymorphonuclear  leucocytes, monocytes, mastocytes and plasma cells (IgE secreting B lymphocytes).

Immune System: an organized collection of components which the body uses to defend  itself against infection by pathogenic agents in the environment.

Immunity: the body's ability both to resist external agents by means of the "immune system",  in particular infectious agents (virus, bacteria or parasites) and to tolerate other agents or  external products such as foods that we eat, for example.

Immunoglobulin: synonymous for "antibody" (abbreviated Ig). Five different types of  immunoglobulin exist: IgM, IgG, IgE, IgD, IgA. Allergic reactions usually are mediated by IgE. Immunotherapy: synonymous for "desensitization".

Inflammation: a local or systemic defense reaction of a tissue, following a trauma (for  example a wound or infection, etc.) which can upset its balance. It is characterized by the  following four major signs:  redness, warmth, tumefaction or swelling, and pain. Often it can be beneficial, allowing identification and elimination of an agent or foreign body and healing.  It sometimes is harmful, either as a result of its location (for example laryngeal edema) or  due to certain bothersome effects which it causes (for example, naso-sinusal polyposis).

Interleukin: a compound (substance) secreted by lymphocytes or macrophages that acts as  a messenger between the different cells of the immune system. These compounds are part  of a larger collection of chemical messengers called "cytokines".

Intolerance: an abnormal (pathological) reaction of the body against an aggressive agent  which the majority of subjects tolerate with no abnormal symptoms, depending or not of an  immune response.

Intradermal Reaction: a skin test designed to screen for an antigen. This test consists of  performing an injection of an allergen with a syringe in the dermis, i.e. in the skin but under  the epidermis. This reaction is read 20 minutes later.