Serum levels of tumor necrosis factor alpha in patients with IgA nephropathy are closely associated with disease severity

BackgroundTumor necrosis factor alpha (TNF-) isconsidered to play an important role in the pathogenesis in IgA nephropathy (IgAN). The correlations between serum TNF- and disease severity in patients with IgAN remain controversial.MethodsConcentrations of serum TNF- of 147 patients with IgAN and 126 healthy subjects were measured by chemiluminescence immunoassay. Correlations with clinicopathological features of patients with IgAN were evaluated.ResultsSerum levels of TNF- [9.20 (7.70-10.60) pg/mL vs. 6.04 (5.11-7.23) pg/mL, P<0.0001]were higher in patients with IgAN than that in healthy subjects. Receiver operating characteristic curve analysis revealed that TNF- had better discrimination between patients with IgAN and healthy controls than estimated glomerular filtration rate [TNF-: (AUC, 0.87; 95% CI, 0.83-0.91; P<0.0001) vs. estimated glomerular filtration rate: (AUC, 0.76; 95% CI, 0.71-0.82; P<0.0001), P=0.007]. Multivariate linear regression analyses showed that serum levels of TNF- were positively correlated with 24-h urine protein excretion (r=0.33, P=0.04), urinary protein to serum creatinine ratio (r=0.33, P=0.03), serum creatinine (r=0.46, P<0.0001) and Cystatin C (r=0.59, P<0.0001) in IgAN and negatively correlated with estimated glomerular filtration rate (r=-0.49, P<0.0001) after adjustment for sex, systolic blood pressure and diastolic blood pressure. Patients with higher mesangial hypercellularity or tubular atrophy/interstitial fibrosis score according to Oxford classification showed higher serum levels of TNF-.ConclusionsOur data showed that serum levels of TNF- detected by chemiluminescence immunoassay was a potential biomarker for evaluating the disease severity in IgAN.