C3 and systemic lupus erythematosus: They possess similar characteristics with lupus nephritis, including immunologic, histologic, and ultrasonographic features such as immunoglobulin (IgG, IgA, and IgM) and complement (C3 and C1q) mesangial deposits; however, it occurs in patients without negative serological findings and no clinical evidence of systemic lupus erythematosus (SLE) [42].