Corticosteroids are frequently used to treat patients with active IgA nephropathy (IgAN); however, there have been few reports describing factors that are predictive of the response to corticosteroid treatment. The purpose of this study is to determine the extent to which fibroblast-specific protein 1-positive (FSP1(+)) cells are predictive of corticosteroid responsiveness in patients with IgAN. METHODS: Fifty biopsy-proven IgAN patients who received corticosteroid therapy were enrolled and followed for 7.1 +/- 3.0 years. FSP1(+) cells were identified using an anti-FSP1 antibody. RESULTS: Twelve patients showed progression of renal impairment or no reduction of urinary protein (non-responders) after steroid therapy. In the remaining 38 patients, renal function was stable during follow-up, and their urinary protein declined to <1.0 g/day (responders). Serum creatinine, estimated GFR, severity of mesangial proliferation, percent glomerulosclerosis/total glomeruli, extent of interstitial damage and FSP1(+) cell number were all significantly higher in non-responders than in responders. Cox regression analysis using two covariates with every possible combination of factors indicated that FSP1(+) cell number was the strongest and most significant predictor of corticosteroid responsiveness. When IgAN patients had >32.6 FSP1(+) cells/HPF at diagnosis, they were the more likely to show steroid resistance. CONCLUSION: FSP1(+) cell number can serve as an excellent predictor of corticosteroid responsiveness in patients with IgAN.

1st Department of Internal Medicine Nara Medical University 840 Shijo Kashihara

Prediction of corticosteroid responsiveness based on fibroblast-specific protein 1 (FSP1) in patients with IgA nephropathy

Komentář [k článku FSP1 jako možný prediktor odpovědi na kortikosteroidy u nemocných s IgA nefropatií].