Significance of C4d expression in minimal change disease and focal segmental glomerulosclerosis

C4d is a by-product of the lectin complement pathway. Glomerular C4d deposition is related to poor prognosis in various forms of immune-mediated glomerulonephritis. The aim of this study was to elucidate the role of the lectin pathway in minimal change disease (MCD) and focal segmental glomerulosclerosis (FSGS). C4d immunohistochemical staining was performed on 130 renal biopsy tissue specimens from patients diagnosed with MCD or FSGS at Seoul National University Hospital. C4d expression was lower in the control group than in the MCD and FSGS groups (0.32 +/- 0.415 vs 1.31 +/- 0.912 and 1.52 +/- 1.05, respectively, P < 0.001 for each). Additionally, C4d expression was higher in cases with nephrotic syndrome than without nephrotic syndrome (1.64 +/- 1.020 vs 1.09 +/- 0.841, P = 0.002). Furthermore, the mean C4d scores were related to the creatinine levels at the final visit in both disease groups (P = 0.010, R-2 = 0.051). These results suggest that the lectin pathway might be associated with the pathogenesis and prognosis of MCD and FSGS.