Considering the deposits of Igs (IgG, IgM, IgA) and complement proteins (C1q, C3, C4, Mannose Binding Lectin (MBL)) detected in SLE patient kidney biopsies [147,148] as well as the quantity of anti-C1q deposited in these glomeruli [149], a contribution of the complement activation in the kidney to the development of LN was suggested [148]. This evidence concerns the gene C3 and lobular neoplasia.