['B-cell-activating factor belonging to the tumor necrosis factor family (BAFF) has been found to have the function of activating B cells and participating in the class switching of B cells; however, its clinical application needs further study. In the present study, the serum BAFF levels of patients with IgA nephropathy (IgAN) with different histopathological phenotypes were measured.', 'Levels of serum BAFF in 153 patients with IgAN, 55 healthy controls and 20 disease controls were recorded using commercially available ELISA kits. Their correlations with clinical and histopathological features of patients with IgAN were further evaluated.', 'Levels of serum BAFF in patients with IgAN were significantly higher than in controls. Serum BAFF levels were significantly higher in patients with mesangial hypercellularity and segmental glomerulosclerosis than in those without. Serum BAFF levels were associated with the severity of tubular atrophy/interstitial fibrosis. Serum BAFF levels were significantly positively correlated with estimated glomerular filtration rate and serum creatinine. Patients with elevated serum BAFF levels showed significantly greater severity in clinical and histopathological stages.'] Is serum BAFF elevated in patients with IgA nephropathy and associated with clinical and histopathological features?