Nora Barrett

This work was supported by the of the National Institute of Allergy and Infectious Diseases, (grant no. ZIA AI001175 to M.S.L.). Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest.

Paradigms and perspectives Factor H–related proteins and their associated disorders Section snippets The FH-related proteins of the human FH protein family Factor H (FH) is one of the complement regulatory proteins acting at the level of the central C3 component, and its main role in the downregulation of alternative pathway activation and the amplification loop has been known for a long time (Fig 1, A2,3).

Section snippets Activation, key functions, and regulation The mammalian complement system encompasses more than 50 proteins, many of which are secreted by the liver. This includes fundamental components such as C3 and C5 as well as fluid-phase regulatory molecules.