**Background of CFH Antibodies**
Complement Factor H (CFH) is a critical regulatory protein in the complement system, primarily inhibiting the alternative pathway to prevent excessive immune activation and host tissue damage. Dysregulation of CFH, whether due to genetic mutations, autoantibodies, or functional impairment, is linked to several diseases, including atypical hemolytic uremic syndrome (aHUS), age-related macular degeneration (AMD), and C3 glomerulopathy (C3G).
CFH autoantibodies, first identified in aHUS patients, are polyclonal IgG antibodies that bind to the C-terminal region of CFH (domains 19-20), disrupting its ability to protect host cells from complement-mediated damage. This leads to uncontrolled complement activation on endothelial cells, causing thrombotic microangiopathy. In AMD, CFH polymorphisms (e.g., Y402H) and autoantibodies may contribute to chronic inflammation in the retina.
Research into CFH antibodies has expanded diagnostic and therapeutic approaches. Detection methods like ELISA aid in identifying autoimmune-associated aHUS or C3G. Therapies targeting complement pathways (e.g., eculizumab) or removing autoantibodies (plasma exchange) are clinically used. Recent studies also explore monoclonal antibodies to restore CFH function or block pathogenic autoantibodies.
Understanding CFH antibodies highlights the interplay between genetic susceptibility, autoimmunity, and complement dysregulation, offering insights for precision medicine in complement-related disorders.