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How do autoimmune reactions cause chronic inflammation?

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Pathways of complement activation — inflammation The main function of complement proteins is to aid in the destruction of pathogens by piercing their outer membranes (cell lysis) or by making them more attractive to phagocytic cells such as macrophages (a process known as opsonization). Some complement components also promote inflammation by stimulating cells to release histamine and by attracting phagocytic cells to the site of infection.

Autoimmune reactions cause chronic inflammation because the immune system becomes sensitized to the body’s own healthy tissues, treating them as foreign antigens. Unlike acute inflammation, which is a temporary defense mechanism intended to eliminate an injurious agent and promote healing, chronic inflammation in autoimmune conditions is an independent, prolonged response where the stimulus—the body's own components—cannot be removed.12

This process occurs through several mechanisms:
* Direct Attack: Cell-killing lymphocytes may launch direct assaults on healthy tissues.3
* Antibody Binding: Circulating antibodies may bind to cells, interfering with their function or assisting in their destruction.3
* Immune Complex Deposition: Antibody-antigen combinations can lodge in tissues, triggering reactions that attract white blood cells (such as granulocytes) that release damaging enzymes.34

The hallmark of this chronic state is the persistent infiltration of the site by macrophages, lymphocytes, and plasma cells. These cells release factors that drive ongoing tissue damage and functional impairment, as seen in diseases like rheumatoid arthritis.14