top of page

What's this?

The inflammatory response - the mechanisms of the inflammatory reaction

Inflammation or inflammatory reaction is a reaction of the living and vascularised tissues of the immune system to an external (infection, trauma, burn, allergy, etc.) or internal (cancerous cells) aggression. It is a process that involves vascular and cellular phenomena and the release of several types of mediators including prostaglandins. However, the inflammatory reaction can also be harmful. The use of drugs, particularly anti-inflammatory drugs, is sometimes necessary to treat inflammation.

  • Usually, inflammation is a beneficial process that aims to eliminate the pathogen and repair tissue damage.

  • Sometimes inflammation can be harmful when it is maladaptive or uncontrolled. This is possible by:

    • the aggressiveness of the pathogen

    • his persistence

    • the seat of inflammation

    • abnormalities in the regulation of the inflammatory process

    • a quantitative or qualitative abnormality of the cells involved in inflammation


In general, inflammation is manifested by:

  • redness ( erythema corresponding to une  vasodilation  locale);

  • swelling ( edema );

  • a feeling of warmth;

  • pain that seems to pulsate;

  • a possible alteration in the functioning of the organ concerned (eg difficulty in moving (functional impotence) in the case of a joint).

An inflammatory reaction is most often local. It involves several elements that are specific to an activation of the immune system. There is a role for white blood cells, enzymes and chemical mediators.


A tissue lesion, following an attack, leads to the mobilization of white blood cells which will produce or promote the production of other molecules which in turn are responsible for the symptoms.


Aggression of cells by infection or injury activates cells which release inflammatory mediators such as histamine, pro-inflammatory cytokines and other active compounds. The functional consequences of this activation are the elimination of the pathogen and/or the repair of the lesion.

In the inflammatory reaction, the fatty acids of the cell membrane are transformed into, among other things, prostaglandins . Biosynthesis is significantly increased in inflamed tissues and this contributes to the development of the cardinal signs of acute inflammation.

bottom of page