Zonulin, as a marker of intestinal permeability, is elevated in IgA nephropathy and IgA vasculitis with nephritis

Background Immunoglobulin A nephropathy (IgAN) and IgA vasculitis with nephritis (IgAV-N) are considered related diseases and share some similar clinicopathologic phenotypes. Elevated circulating galactose-deficient IgA1 (Gd-IgA1)-containing immune complexes and mucosal immunity were associated with the pathogenesis of IgAN and IgAV-N. Recently, studies have identified that the zonulin level, as a modulator of intestinal permeability, is significantly elevated in several inflammatory and autoimmune-related diseases. However, whether zonulin also plays a role in IgAN and IgAV-N is not clear. Methods A total of 73 IgAV-N patients, 68 IgAN patients and 54 healthy controls were assessed for circulating zonulin and Gd-IgA1 levels by enzyme-linked immunosorbent assay. The diagnostic efficiency of the combination of zonulin with Gd-IgA1 was evaluated by the area under the receiver operating characteristic curve (AUC) and integrated discrimination improvement (IDI) analysis. Results Compared with healthy controls, we found that both IgAV-N and IgAN patients had elevated zonulin and Gd-IgA1 levels (P Conclusion Elevated circulating zonulin levels were detected in both patients with IgAV-N and those with IgAN. Combined detection of circulating zonulin and Gd-IgA1 is recommended as a noninvasive diagnostic biomarker for IgAV-N and IgAN.