IL-22 + CD4 + T-cells in patients with active systemic lupus erythematosus

Abstract

Interleukin-22 (IL-22) is a regulator of autoimmune diseases. However, the role of IL-22⁺CD4⁺ T-cells in the pathogenesis of systemic lupus erythematosus (SLE) remains unclear. This study is aimed at elucidating the potential role of IL-22 and IL-22⁺CD4⁺ T-cells in patients with SLE. A total of 22 patients with freshly diagnosed SLE and 18 age-/gender-matched healthy controls (n = 18) were evaluated for the frequency of different types of IL-22-producing CD4⁺ T-cells by flow cytometry analysis following in vitro stimulation. The concentrations of plasma IL-22, IL-17A, IFNγ, serum complement factors (C3, C4), C-reactive protein (CRP), antidouble-stranded (ds) DNA and anti-Smith (Sm) antibodies were measured. The potential association among these measures was analyzed. The percentages of IL-22⁺IL-17⁻IFNγ⁻, IL-22⁺IL-17A⁻IFN-γ⁺, IL-22⁻IL-17⁺IFN-γ⁻ and IL-22⁺IL-17⁺IFN-γ⁻ CD4⁺ T-cells and the levels of plasma IL-22 and IL-17A in the patients were significantly higher than that in the healthy controls (P < 0.01). The frequency of Th22 cells was correlated positively with that of Th17 and IL-22⁺IL-17⁺ CD4⁺ T-cells, and the frequency of Th17 and IL-22⁺CD4⁺ T-cells was correlated positively with the values of SLE disease activity index (SLEDAI), but not with the values of CRP, ERS and C3 in SLE patients. Our data suggest that both Th17 and IL-22⁺CD4⁺ T-cells may participate in the pathogenesis of SLE.