Role of the innate and adaptive immune system
The innate immune system provides a critical protective function during the initial phase of pathogen invasion (infection) or endogenous product generated by tissue injury. It is mediated by innate immune cells such as macrophages or dendritic cells, is very reactive (within hour) and nonspecific through processes called phagocytosis, inflammation and cytotoxicity. The innate immune system will kick start a second wave of defense, the adaptive immune system for a more specific immune response and feedback on inflammatory response, mainly mediated by cells called lymphocytes B and T.
Activation of the cells of the innate immune system results in the production of pro-inflammatory cytokines and chemokines and more specifically the production of Interleukin 1-family chemokines, IL1 and IL18, through specialized cytoplasmic multimeric protein structures called inflammasomes, found within phagocytic cells (macrophages and dendritic cells).
Inflammasomes complex are also implicated in the inflammation-induced cell death with characteristics of apoptosis and necrosis called “pyroptosis”. It appears that the aberrant activation of the inflammasomes is a risk factor for the emergence of autoimmune, autoinflammatory, chronic inflammatory, and metabolic diseases. Accordingly, activation of the inflammasomes should be controlled to avoid unwanted host damage and too much inflammation.
Infection, autoinflammation and autoimmunity
| Infection | Autoinflammation | Autoimmunity | |
|---|---|---|---|
| Cause | Microbal pathogens, such as bacteria or viruses | - Genetic mutations of inflammasome - Cellular oxidative stress - Enviromental triggers |
Autoantibodies, directed against own tissue |
| Symptoms | Systemic, surch as fever, rash, muscle pain, nausea, fatigue | Systemic, surch as fever, rash, muscle pain, nausea, fatigue | Specific symptoms, depending on the tissue/ organ and its associated functions being destroyed by autoantibodies and subsequent inflammation |
| Immune system | - Innate immune systeme - Adaptative immune system - Complement system |
Innate immune system | - Adaptive immune system |
| Immune cells | Monocytes, macrophages, neutrophils, natural killer cells, lymphocytes | Monocytes, macrophages, neutrophils, natural killer cells | Lymphocytes, macrophages |
| Elevated molecules in blood | - Antibodies - Immune messengers (cytokines) - Immune attractants ( chemokines) - Plasma proteins of complement system |
- Immune messengers (cytokines) - Immune attractants ( chemokines) |
- Autoantibodies - Immune messengers (cytokines) - Plasma proteins of complement system |
| Therapy | Antibiotics, antivirals, antifungals, antiprotozoals, antihelminthics. |
Steroids Biologicals targeting cytokine surch as IL-1, IL-6 or IL-18 |
Steroids methotrexate Biologicals targeting TNF, IL-6, B or T lymphocytes, adhesion molecules,... |
