Autoantibodies in systemic autoimmune diseases: specificity and pathogenicity

Area of Science:

• Immunology
• Autoimmunity
• Molecular Biology

Background:

• Autoantibodies play a key role in autoimmune diseases.
• Understanding the initiation and pathogenicity of autoantibodies is crucial for developing targeted therapies.
• Current knowledge gaps exist regarding the precise mechanisms driving autoreactive B cell survival and autoantibody production.

Purpose of the Study:

• To review the mechanisms underlying autoantibody production and pathogenicity.
• To emphasize the role of targeted self-antigens in initiating autoimmune responses.
• To propose a hypothesis on how autoreactive B cells escape tolerance.

Main Methods:

• This is a review article, synthesizing existing research and data.
• Focuses on analyzing the triggers for autoantibody initiation.
• Examines the role of specific self-antigens and their modifications.

Main Results:

• Autoantibody production is initiated by release of intracellular antigens, modified self-antigens, and molecular mimicry.
• Autoreactive B cells with specificity for Toll-like receptor (TLR) ligand self-antigens escape tolerance through combined B cell receptor (BCR) and TLR activation.
• Pathogenic autoantibodies form immune complexes that activate myeloid cells, creating a pro-inflammatory environment that further erodes tolerance.

Conclusions:

• Self-antigens that are TLR ligands are critical targets for pathogenic autoantibodies.
• The dual activation of BCR and TLR is a key mechanism for escaping self-tolerance.
• Immune complex formation and subsequent myeloid cell activation perpetuate autoimmunity by impairing tolerance mechanisms.