CD147 renal expression as a biomarker for progressive IgAN

Background/aims Recent studies have demonstrated that tubulointerstitial injury can predict renal outcomes better than the other histological parameters in patients with IgA nephropathy (IgAN). CD147 is a key regulator of renal tubulointerstitial fibrosis in cellular and animal models. However, it is not clear whether the expression of CD147 correlates with tubulointerstitial injury in IgAN patients. Methods We analyzed the degree of CD147 expression and localization in renal biopsy tissues from IgAN patients and correlated their immunostaining scores with clinical and histological parameters. Results Elevated CD147 expression was found in the basolateral membrane of renal tubules in IgAN patients; however, in normal kidney samples, positive staining for CD147 was not found in the tubular epithelial cells (P = 0.000). CD147 protein expression in the renal tubules showed a negative correlation with estimated glomerular filtration rate (eGFR; r = -0.600, P = 0.000) and a positive correlation with serum creatinine (Scr; r = 0.322, P = 0.002) and tubulointerstitial lesions (r = 0.525, P = 0.000). Moreover, a high level of CD147 correlated with the activation of Slug expression and E-cadherin repression in patients with IgAN. Kaplan-Meier survival curves showed that elevated CD147 expression was associated with decreased renal survival. Multivariate analyses further demonstrated that a high CD147 immunostaining score was an independent predictor of renal outcome in patients with IgAN (HR = 8.731, P = 0.041). Conclusion CD147 expression is associated with tubulointerstitial injury and predicts renal prognosis in IgA nephropathy. CD147 may be an early marker for tubulointerstitial injury IgA nephropathy.