Abstract:Objective To preliminarily explore the frequency of T-helper 22 (Th22) cells in the peripheral blood and the serum level of interleukin-22 (IL-22) in patients with lupus nephritis (LN) and their correlation with Systemic Lupus Erythematosus Disease Activity Index (SLEDAI).Methods In our study, 10 healthy people were assigned into the healthy control group (HC group), 20 patients with LN the LN group, and 20 patients with systemic lupus erythematosus (SLE) but intact kidneys the SLE group. The frequency of Th1 and Th22 cells was detected by flow cytometry, and the serum level of IL-22 was determined by enzyme-linked immunosorbent assay (ELISA). Pearson correlation analysis was used to evaluate the relationship between the level of IL-22 and the frequency of Th22 cells in LN group, as well as the relationship between the two and SLEDAI.Results The levels of C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and immunoglobulin in LN group and SLE group were significantly higher than those in HC group, while the serum levels of complement component 3 (C3) and 4 (C4) were significantly lower in the LN group and SLE group compared with the HC group (P < 0.05). There was no significant difference in the frequency of Th1 cells among the three groups (P > 0.05). The frequency of Th22 cells and the level of IL-22 in LN group and SLE group were higher than those in HC group (P < 0.05), but there was no significant difference in the frequency of Th22 cells and the level of IL-22 between LN group and SLE group (P > 0.05). In addition, there was a positive correlation between the level of IL-22 and the frequency of Th22 cells in LN patients (r = 0.804, P = 0.002), and they were also positively correlated with SLEDAI score (r = 0.342 and 0.448, P = 0.032 and 0.016).Conclusions Th22 cells and IL-22 are involved in the development of SLE and LN, and both of them are positively correlated with SLEDAI score.