By : abeer ahmed ☺

Allergy and inflamma-tion

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Allergy :•An allergy occurs when the body reacts to foreign par-ticles.•These particles, such as tree pollen or dust mites, are called antigens, or allergens, and are normally harm-less.•the immune system of a person with allergies views the allergens as harmful.•Following the body’s first contact with an allergen, white blood cells produce antibodies that prepare the im-mune system for the same allergen the next time it enters the body.

Figure showing a WBC releasing antibodies to allergen after first exposure

•The antibodies formed attach themselves on the surface of cells such as basophils and mast cells.

•On the 2nd exposure Ag-Ab reaction occurs leading to release chemicals such as leukotrienes, prostaglandins, and histamine.•Those chemicals bind to the cells and blood vessels leading to inflammation and swelling.

•Normally to reduce inflammation, the brain signals the adrenal glands to produce a hormone called cor-tisol.•Cortisol works against allergens by acting on re-ceptors in the cytoplasm of various cells.•Once bound, cortisol-receptor complex enters into the nucleus. There it binds to the DNA and prevents the creation of proteins responsible for the release of inflammatory chemicals.

Figure showing cortisol entering nucleus of various cells

Figure showing cortisol preventing transla-tion of inflammatory proteins

adrenal gland

•Corticosteroids are hormones secreted by adrenal (suprarenal) gland into bloodstream.

Figure showing adrenal gland secretin cortisol

•Cortisol has many functions but most impor-tantly extra cortisol can be produced to help man-age the effects of infection, trauma, and emotional stress.•In this instance, otherwise healthy tissue in the knee is seen as infectious and is attacked by the body’s own white blood cells causing a painful inflammation.•Sometimes however, even the extra production ofnatural cortisol does not adequately control theimmune system response.•Corticosteroids which are drugs block white blood cells from attacking the tissue and decrease the inflammatory-causing substances these im-mune cells produce.

Figure showing corisol modulating action of WBCs on inflammation by en-tering the nucleus and inhibiting translation of inflammatory proteins