Alterations in oxidative stress biomarkers and helper T‐cell subgroups in patients with periodontitis and IgA nephropathy

Abstract Objective Investigating the changes in the oxidative stress levels and helper T lymphocyte (Th) subsets in patients with periodontitis and IgA nephropathy (IgAN) to determine their relationship. Background IgAN has a high prevalence, poor prognosis, and no effective cure. Accumulating evidence has implicated a close relationship between periodontitis and chronic kidney diseases, in which both IgAN and chronic periodontitis show chronic inflammation and abnormal metabolism. However, few studies have been conducted on the relationship between the two diseases from this perspective. Methods We divided 86 IgAN patients into patients with healthy periodontium (IgAN‐H, n = 34) and patients with periodontitis IgAN (IgAN‐P, n = 52); moreover, we divided 72 systemically healthy participants into patients with periodontitis (H‐P, n = 35) and participants with healthy periodontium (H‐H, n = 37). The proportions of Th subsets in peripheral blood were estimated using flow cytometry. Cytokine levels in plasma were assessed using cytokine assay kits. Enzyme‐linked immunosorbent assay was used to evaluate the plasma levels of oxidative stress. Results Our results from analyzing the Th cell subsets indicated that Th2 cell counts in the IgAN‐P group were significantly lower than those in the IgAN‐H group, while Th17 cell counts were increased ( p < 0.05). Moreover, the Th1/Th2 ratio and interleukin‐6 levels in the IgAN‐P group were significantly higher than those in the H‐H group ( p < 0.01). Compared with that in the H‐H group, in the remaining three groups, plasma total oxidation state (TOS) levels were increased ( p < 0.01), while plasma total antioxidant state (TAS) levels were decreased ( p < 0.05). Furthermore, estimated glomerular filtration rate was negatively correlated with the probing depth and gingival bleeding index. IgAN was a risk factor for periodontitis, while TAS was a protective factor for periodontitis. The oxidative stress index (OSI) might be valuable for distinguishing periodontitis patients from healthy controls (area under the receiver operator characteristic curve = 0.951). Conclusion IgAN is an independent risk factor of periodontitis, and the Th17 cell‐mediated inflammatory response might be associated with the occurrence of periodontitis in patients with IgAN. Patients with coexisting IgAN and periodontitis exhibit increased oxidative stress, in which TOS and OSI are potential biomarkers for diagnosing periodontitis.