ABSTRACT
BACKGROUND: TGF-beta is involved in the pathogenesis of various kidney diseases characterized by glomerulosclerosis and tubulointerstitial fibrosis. It is reported that urinary TGF-beta reflects the grade of interstitial fibrosis in glomerular disease. Here, we evaluated the relationship between the histological findings and beta ig-h3 in IgA nephropathy. METHODS: In patients with IgA nephropathy, we measured blood pressure (BP), serum creatinine, 24-hour urinary protein excretion (UTp), creatinine clearance (Ccr), serum and urine beta ig-h3 levels, and urine TGF-beta levels at the time of renal biopsy. Histologic findings were semiquantitively scored according to the extent of glomerulosclerosis (GG), tubulointerstitial fibrosis (TIG) and hyaline arteriolosclerosis (HA) by the criteria suggested by To. Semiquantitive scoring of immunohistochemistry for beta ig-h3 was done. RESULTS: Mean BP 95.4+/-14.5 mmHg, serum creatinine 1.06+/-0.35 mg/dL, 24-hour UTp 1, 423+/-1, 439 mg/day, and Ccr was 97.84+/-59.73 mL/min. The number of patients that showed GG 3 were 5, GG 2 was 1, GG 1 were 12. And, the number of patients that showed TIG 3 were 2, TIG 2 were 5, TIG 1 were 11. HA was shown in 4 patients. beta ig-h3 immunostaining was observed in glomerular Bowman's capsules and basement membrane of proximal tubules. The degree of beta ig-h3 immunostaining was positively correlated with the degree of glomerulosclerosis (r=0.72, p<0.001), interstitial fibrosis (r=0.91, p<0.001), serum creatinine (r=0.592, p<0.05) and Ccr (r=-0.626, p<0.05), but not with 24-hour UTp. Serum and urine beta ig-h3 levels did not correlate with any of these parameters. CONCLUSION: Renal beta ig-h3 expression in patients with IgA nephropathy may be related to glomerulosclerosis and interstitial fibrosis. However, urinary beta ig-h3 levels did not represent the pathologic changes of IgA nephropathy. Long-term study to measure renal beta ig-h3 expression and urinary beta ig-h3 is required to elucidate the roles of beta ig-h3 in IgA nephropathy.