Autoimmunity versus tolerance: can dying cells tip the balance?

Area of Science:

• Immunology
• Cell Biology
• Pathology

Background:

• Apoptosis is a regulated cell death process crucial for tissue homeostasis.
• Efficient clearance of apoptotic cells prevents inflammation and maintains immune tolerance.
• Dysregulation of apoptosis and its clearance are implicated in autoimmune disorders.

Purpose of the Study:

• To review the role of apoptosis and apoptotic cell clearance in immune tolerance.
• To explore the link between defects in cell death pathways and autoimmunity.
• To discuss how altered cell death impacts the balance between tolerance and autoimmune responses.

Main Methods:

• Literature review of studies on apoptosis, immune tolerance, and autoimmunity.
• Analysis of mechanisms involving apoptotic cell uptake by antigen-presenting cells.
• Examination of genetic defects in apoptosis and their association with autoimmune diseases.

Main Results:

• Physiological apoptosis and efferocytosis promote peripheral immune tolerance.
• Necrotic cell death or pathogen infection can activate immune responses.
• Defective apoptosis (e.g., ALPS) or impaired clearance leads to autoantibody production and autoimmunity.

Conclusions:

• Cell death pathways and their clearance are critical for maintaining immune homeostasis.
• Disruptions in apoptotic processes can precipitate autoimmune conditions.
• Understanding these mechanisms is key to developing therapies for autoimmune diseases.