Role of Anti-ficolin-3 Antibodies in the Pathogenesis of Lupus Nephritis

Detailed Summary

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease characterized by the production of multiple autoantibodies and accumulation of immune complexes resulting in systemic inflammatory response and tissue damage. Although the underlying mechanisms are complex, defects in dying cells elimination are likely to contribute to autoantigen overload and development of autoimmunity. Molecules important in damaged cell clearance, such as early complement components, may thus have a protective role. According to this hypothesis, deficiencies in C1q and MBL, the recognition proteins of the classical and lectin pathways of complement; are associated with increased susceptibility to SLE. In the proposed project, the investigators will investigate the involvement of another related recognition protein, ficolin-3, which activates the complement lectin pathway and recognizes necrotic cells. The investigators have shown in a recent study a significant association between the presence of anti-ficolin-3 antibodies and active nephritis in patients with SLE. However, the possible involvement of anti-ficolin-3 antibodies in the pathogenesis of SLE and particularly in lupus nephritis (LN) remains to be elucidated. This project plans to investigate the role of ficolin-3 and ficolin-3 autoantibodies in LN. The study associates two aspects, aiming at deciphering the role of anti-ficolin-3 antibodies in dying cells recognition and investigating the role of ficolin-3 in renal tissue damage. This pilot study will be performed for 14 patients with active LN on serum and renal biopsy, realized for routine patient care. The investigators will explore the effect of anti-ficolin-3 antibodies purified from the patient serum on ficolin-3-dependent necrotic cells recognition, in relation with possible altered clearance of dead cells, which is an important hypothesis of the pathogenesis of SLE. The investigators will also investigate ficolin-3 deposition in renal biopsy, which may contribute to the local formation of immune complexes, leading to complement activation and subsequent inflammation and tissue injury.

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