Autoantibodies and therapeutic antibodies against complement factor H

Area of Science:

• Immunology
• Complement System Biology

Background:

• The complement system is vital for immune defense but requires strict regulation to prevent host tissue damage.
• Factor H is a key regulator of the alternative complement pathway, controlling activation on cell surfaces and in fluid phases.
• Impairment of Factor H function, through genetic factors, competing proteins, or autoantibodies, can disrupt complement regulation.

Purpose of the Study:

• To review the presence and impact of anti-Factor H autoantibodies in various diseases.
• To explore how these autoantibodies affect Factor H function and complement activation.
• To discuss the potential therapeutic implications of understanding anti-Factor H autoantibodies.

Main Methods:

• Literature review of studies reporting anti-Factor H autoantibodies in different diseases.
• Analysis of reported effects of autoantibodies on Factor H regulatory functions.
• Synthesis of current understanding of autoantibody binding sites and functional consequences.

Main Results:

• Anti-Factor H autoantibodies are found in various conditions, including autoimmune diseases and cancer, beyond previously known associations like atypical hemolytic uremic syndrome.
• These autoantibodies can either inhibit or enhance Factor H activity, contingent upon the specific epitopes targeted.
• The precise pathogenic role of anti-Factor H autoantibodies in some diseases remains to be fully elucidated.

Conclusions:

• Anti-Factor H autoantibodies are implicated in a broader spectrum of diseases than previously recognized.
• Understanding the epitope-specific effects of these autoantibodies is crucial for assessing their pathogenicity.
• Targeted interventions against pathological anti-Factor H autoantibodies may offer therapeutic benefits, and anti-Factor H antibodies themselves could be explored as therapeutic agents.