CYTOKINES & AUTOIMMUNITY
Cytokines are tiny proteins released by cells to modify the role of the same or another cell. They include interleukins, chemokines, interferons, adipokines and others. They are chemical intracellular messengers and are found sizably in the immune system to help initiate and control the immune response. They bind to specific receptors on the cell surface of target cells and switch on the intracellular signalling cascade via complex interactions. Cytokines are key modulators of acute and chronic inflammation. Dysregulation of cytokine production or action is thought to have a key role in the development of Autoimmune diseases.
The Complex Cytokine Network
All Immune cells have distinct roles and communicate with other cells via cytokines. For example, Macrophages can use cytokines to stimulate specific responses by B and T cells and non-specific responses by other cell types. T cells secrete cytokines to coordinate and stimulate immune responses to specific antigens. Activation and modulation of eosinophils, neutrophils and basophils are also via cytokines.
Reference: (Zhang, Jun-Ming MSc, MD*; An, Jianxiong, 2007)
Types of Cytokines
Pro-inflammatory cytokines and Anti-inflammatory cytokines are the two types of cytokines that exist.
Pro-inflammatory cytokines (eg. IL-1beta, IL6, TNF-alpha) activate the immune and cytokine response.
Anti-inflammatory cytokines (eg. IL-4, IL-10, IL-11, IL-13, TGF-Beta) regulate the pro-inflammatory cytokines.
A Cytokine Storm
An effective immune response requires a balance between sufficient cytokine production to eliminate a threat and avoidance of a hyperinflammatory, overblown and dysregulated response in which an overabundance of cytokines may cause tissue damage. The term “cytokine storm” is an abrupt upregulation of cytokines provoking the inflammatory process, resulting in high levels of circulating cytokines and immune-cell hyperactivation. A cytokine storm can be triggered by pathogens, cancers and Autoimmune conditions.
Reference: (David C. Fajgenbaum, and Carl H. June, 2020)