chronic inflammation

Chronic Inflammation

• Chronic inflammation is a prolonged inflammatory response with a duration of weeks or months, often associated with tissue damage and fibrosis.

Immune Cells in Chronic Inflammation

• Macrophages are the dominant cell type in chronic inflammation and are responsible for tissue remodeling and repair.
• Activated T lymphocytes secrete cytokines like interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), contributing to inflammation and tissue damage.
• Activated B lymphocytes secrete antibodies, which can contribute to inflammation in autoimmune diseases.
• Macrophages display antigens to T cells, initiating the immune response.
• T cells recruit and activate macrophages during chronic inflammation.

Macrophage Activation

• Macrophages can be activated by different stimuli and play a diverse role in inflammation.
• Classical activation (M1): induced by IFN-γ and TNF-α, leads to production of pro-inflammatory cytokines and reactive oxygen species, contributing to inflammation and tissue damage.
• Alternative activation (M2): induced by IL-4 and IL-13, promotes tissue repair, angiogenesis, and immune suppression, contributing to resolution of inflammation.

Macrophage Functions in Chronic Inflammation

• Macrophages play a crucial role in both perpetuating and resolving inflammation.
• In host defense against microbes, macrophages phagocytose and kill pathogens.
• In chronic inflammation, macrophages contribute to both tissue repair and damage, depending on their activation state.
• M1 macrophages contribute to tissue damage through the production of pro-inflammatory cytokines and reactive oxygen species.
• M2 macrophages promote tissue repair, angiogenesis, and immune suppression.

Role of B cells

• Activated B lymphocytes produce antibodies which are responsible for recognizing and neutralizing specific antigens. These antibodies can contribute to chronic inflammation in autoimmune diseases.