{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"Factor H or Complement Factor H (CFH), is the major soluble inhibitor of complement, where its binding to self markers (i.e. particular glycan structures) prevents complement activation and amplification on host surfaces. Mutations and polymorphisms that affect recognition of self markers by Factor H are associated with diseases of complement dysregulation, such as age-related macular degeneration and atypical hemolytic uremic syndrome. In addition, pathogens and cancer cells can hijack Factor H to evade the immune response."}]},{"type":"paragraph","children":[{"type":"text","value":"Lung, Ovarian, Glial and Colon Cancer cells show enhanced expression and surface binding of soluble regulators, including Factor H. Factor H has been shown to be expressed by human Breast Cancer cells, which correlates with the presence of immunosuppressive macrophages, Breast Cancer recurrence and severity of the disease. Lung cancer cells may develop a protective mechanism against complement attack by expressing and binding Factor H to their cell membranes. Additionally, it has been demonstrated that Factor H is upregulated by constitutive activation of STAT4, which is accounted for by SOCS silencing in Lung Cancer cells. Several studies have also suggested the importance of Factor H in the protection of tumor cells against complement activation. The importance of Factor H expression for the protection of cancer cells in vivo will help to elucidate the mechanisms used by tumor cells to avoid complement activity and assist in the design of more efficient complement-mediated immunotherapies."}]},{"type":"paragraph","children":[{"type":"text","value":"It has been demonstrated that SARS-CoV-2 spike proteins activate complement by engaging the alternative pathway of complement, which may explain many of the clinical manifestations (microangiopathy, thrombocytopenia, renal injury, and thrombophilia) and that blocking this process by inhibiting factor D or C5 could mitigate SARS-CoV-2–induced immunopathology. Addition of Factor H mitigates this complement attack. It has been suggested that a subset of patients with COVID-19 may have a genetic predisposition associated with complement dysregulation."}]}]}