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


CONCLUSIONS
FSP1(+) cell number can serve as an excellent predictor of corticosteroid responsiveness in patients with IgAN.
Harada
Koji
K
1st Department of Internal Medicine, Nara Medical University, 840 Shijo, Kashihara, Nara 634-8522, Japan.
Akai
Yasuhiro
Y
Yamaguchi
Yukinari
Y
Kimura
Kuniko
K
Nishitani
Yoshiharu
Y
Nakatani
Kimihiko
K
Iwano
Masayuki
M
Saito
Yoshihiko
Y
D000293:Adolescent; D000305:Adrenal Cortex Hormones / Q000627:therapeutic use*; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002452:Cell Count; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000473:pathology; D005500:Follow-Up Studies; D005922:Glomerulonephritis, IGA / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D008875:Middle Aged; D000071999:S100 Calcium-Binding Protein A4; D016896:Treatment Outcome; D055815:Young Adult
D000305:Adrenal Cortex Hormones; D015415:Biomarkers; D002135:Calcium-Binding Proteins; D000071999:S100 Calcium-Binding Protein A4; C077591:S100A4 protein, human