C4A and kidney disorder: C reactive protein, CRP: white blood cell count, WBC: red blood cell count, RBC: hemoglobin, Hb: platelet count, PLT: glomerular filtration rate, GFR: complement C3, C3: complement C4, C4: antinuclear antibodies, ANA: anti-double stranded DNA antibodies, anti-ds DNA Ab: 24 hour urinary proteins, proteinuria g/24h, urinary proteins and creatinine ratio, U p/cre: renal disease activity index, SLEDAI/r.