Prognostic value of connective tissue growth factor and c-Myb expression in IgA nephropathy and Henoch-Schonlein purpura-A pilot immunohistochemical study

Aim: Adverse and advanced prognostic signs in IgA nephropathy (IgAN) are interstitial fibrosis and tubular atrophy, but early predictors of bad outcome are still lacking. We investigated expression of connective tissue growth factor (CTGF) and c-Myb in renal biopsies of IgAN and Henoch-Schonlein purpura (HSP), because these gene products are indirectly included in fibrosis and epithelial-mesenchymal transition (EMT). Methods: The sample included 23 patients and 8 controls who underwent nephrectomy due to renal cancer. The slides cut from the paraffin blocks were prepared for standard indirect immunoflourescence, using antibodies to CTGF and c-Myb. Ten high-power non-overlapping fields were photographed on Olympus IX51 microscope. Average percent of positive tubular cells, as well as number of positive cells per glomerulus were calculated. Results: The cytoplasmic tubular CTGF expression was higher in IgAN/HSP than in controls (P < 0.001), whereas no difference was found in glomeruli (P = 0.437). The nuclear c-Myb expresssion in glomeruli and tubules was higher in IgAN/HSP than in controls (P < 0.05). In the follow-up, decline in renal function correlated with glomerular and tubular c-Myb, as well as tubular CTGF expression (all P < 0.05). Conclusion: Our results proposed c-Myb and CTGF as novel, early and sensitive markers of chronic kidney disease and worse renal outcome, but larger series are needed.