Interleukin (IL)-22 belongs to the IL-10 family of cytokines. IL-22 exerts its biological effects via members of the cytokine receptor family class 2. CD4+ T helper (Th) cells predominantly producing IL-22 have been designated as Th22 cells. IL-22/Th22 cells are functionally related to IL-17/Th17 cells, but are distinctly different. Both IL-22 and IL-17 are cytokines recruiting neutrophils in response to microbe invasion. In chronic inflammation, IL-22 mediates protective and regenerative processes, whereas IL-17 cytokines tend to induce inflammation. Studies found that increased IL-22 levels and Th22 cells in peripheral blood were associated with disease activity in patients with systemic lupus erythematosus (SLE), but decreased IL-22 and Th22 cells were also reported. Here we describe analysis of IL-22 and Th22 cells in peripheral blood quantified by flow cytometry, and correlate our findings with SLE disease activity.