Objective：To investigate the concentrations of secreted protein acidic and rich in cysteine(SPARC) in the serum and urine of patients with IgA nephropathy and its expression in the kidney tissues.Methods: The concentrations of SPARC,tumor necrosis factor-α (TNF-α),interleukin 1β (IL-1β),and interleukin 6 (IL-6) in the serum and urine were measured with enzyme-linked immunosorbent assay（ELISA）.The contents of SPARC protein in the culture medium of human mesangial cell (HMC) and human renal tubular epithelial cell (HKC),which had been treated with IL-6,were determined by ELISA.The expression and distribution of SPARC in IgA nephropathy and normal kidney tissues were observed by immunohistochemistry assay.Results: The concentrations of SPARC in serum and urine of IgA nephropathy patients were higher than those of the normal control subjects ( \[2.43±1.22\] μg/ml vs \[0.69±0.21\] μg/ml,\[7.73±2.81\] μg/ml vs \[1.17±1.03\] μg/ml,P<0.01).The serum levels of TNF-α,IL-1β and IL-6 in IgA nephropathy group were significantly higher than those in the control group (P<0.05); the urinary levels of TNF-α and IL-6 in IgA nephropathy group were also higher than those in the controls (P<0.01).SPARC protein secreted by HKC was higher than that by HMC (P<0.01).SPARC was weakly positive in normal distal cortical tubules.SPARC protein expression in tubular epithelial cells of IgA nephropathy patients was obviously higher than that of the normal controls. Conclusion: The secretion of SPARC by renal tubular epithelial cells is increased in patients with IgA nephropathy,which results in elevation of serum SPARC and may have a protective feedback inhibitory effect on HMC proliferation.