Differentiation and recruitment of IL-22-producing helper T cells in lgA nephropathy

IL-22-producing helper T cells (Th22 cells) have been reported to be involved in lgA nephropathy. However, the mechanisms underlying the differentiation and immune regulation of Th22 cells in lgA nephropathy remain unknown. To elucidate the mechanisms by which Th22 cells differentiate and are recruited into the kidney in lgA nephropathy, the distribution of Th22 cells in both the kidney and blood was determined. Additionally, the impacts of proinflammatory cytokines and antigen presentation in the kidney on Th22 cell differentiation were explored. Specifically, the chemoattractant activities of chemokines produced by the kidney for Th22 cells were investigated. Th22 cells were significantly higher both in the kidney and in the blood in lgA nephropathy mice. IL-1β, IL-6, IL-21 and/or TNF-a promoted Th22 cells differentiation from CD4⁺ T cells. It was observed that kidneys undergoing lgA nephropathy expressed CCL20, CCL22 and CCL27, and kidney supernatants were chemotactic for Th22 cells. This activity was partially blocked by anti-CCL20, anti-CCL22, and anti-CCL27 antibodies, which also potentially improved renal lesions simultaneously. The overrepresentation of Th22 cells in lgAN may be attributable to the actions of kidney chemokines and cytokines. Our data suggest a collaborative loop between the kidney and Th22 cells in lgA nephropathy.