Increased number of Th22 cells and correlation with Th17 cells in peripheral blood of patients with IgA nephropathy.

T-helper (Th) 22 and Th17 cells are involved in the pathogenesis of autoimmune diseases. However, the role of Th22 and correlation with Th17 cells in the pathophysiology of IgA nephropathy (IgAN) remain unknown. In our study, Th22 and Th17 cells in peripheral blood of IgAN patients, non-IgA mesangial proliferative glomerulonephritis (non-IgA MsPGN) patients, and healthy controls were measured by flow cytometry. The concentration of plasma interleukin-22 (IL-22) was examined by enzyme linked immunosorbent assay (ELISA). The results showed that Th22 cells, Th17 cells, and plasma IL-22 were significantly elevated in IgAN patients compared with non-IgA MsPGN patients and healthy controls. Th22 cells showed a positive correlation with the levels of plasma IL-22 in IgAN patients. Moreover, a significantly positive correlation between Th22 cells and Th17 in IgAN patients was observed. Furthermore, IgAN patients with proteinuria showed a higher percentage of Th22 cells than IgAN patients without proteinuria. Our data demonstrated that IgAN had increased frequencies of peripheral Th22, Th17 cells and plasma IL-22, indicating that Th22 along with Th17 cells are involved in the immune responses of IgAN.