Complement factor (CF)

Complement factors are a group of plasma proteins that serve as critical components and regulators of the complement system, an integral part of the innate immune response. This group includes essential enzymes such as Factor B and Factor D, which drive the alternative pathway amplification loop, as well as regulatory proteins like Factor H and Factor I that prevent excessive activation. Dysregulation of these factors is a primary driver in several complement-mediated diseases, including paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), and age-related macular degeneration (AMD). Therapeutic targeting of specific factors, particularly Factor B and Factor D, has led to the development of drugs like iptacopan and danicopan to control overactive complement cascades. However, the systemic inhibition of these factors poses a significant safety risk by increasing susceptibility to life-threatening infections from encapsulated bacteria, most notably Neisseria meningitidis. Monitoring of complement activity through biomarkers like C3 levels and AH50 is essential for managing treatment efficacy and safety. Overall, complement factors are vital therapeutic targets for modulating immune-mediated inflammation and tissue damage.

Other names

Complement system factorsComplement proteinsComplement components

Inhibition of the alternative pathway amplification loop and prevention of C3/C5 convertase formation.