We searched three electronic databases (MEDLINE, Scopus and Web of Science) for observational studies assessing the association between susceptibility to RA (or its clinical presentation) and polymorphisms of the cytokines IL-17A, IL-17F, IL-21 and IL-22.
B cell proliferation inducing cytokine IL-21 was higher expressed in LN biopsies of RA patients compared with HC and expression was not affected by rituximab treatment.
Whereas, CM3D was characterised by a prevailing expression of anti-inflammatory cytokines such as IL-10 and LIF, along with trophic factors involved in different mechanisms leading to tissue regeneration, such as PDGF-BB, FGF-2, I-309, SCF, and GM-CSF; CM2D presented relatively higher levels of IL-6, MCP-1, and IL-21, with recognised pro-inflammatory roles in joint disease and pleiotropic effects in the progression of rheumatoid arthritis (RA).
The aim of this study was to evaluate the relationship between the cytokines IL-15, IL-21, and IFN-γ with the autoantibodies (RF, anti-CCP, anti-MCV, and anti-PADI4) in RA and disease activity.
Interleukin (IL)-17A, IL-21, IL-22, IL-29, and transforming growth factor (TGF)-β have been implicated in the pathogenesis of other inflammatory joint diseases, including rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis.
Higher mRNA expression of Bcl-6 and lower Blimp-1 mRNA expression were observed in patients with RA compared to healthy controls, and the expression level of IL-21 was higher in RA patients, which was also seen in CIA mice.
Fibroblast-like synoviocytes from patients with rheumatoid arthritis (RA-FLSs) were cultured and stimulated for RANKL expression with IL-22 in the absence or presence of various concentrations of l,25(OH)2D3, and JAK-2 inhibitor or p38 MAPK inhibitor at the optimised time point of IL-22 treatment.
Controversial results concerning the association between a polymorphism <i>rs6822844</i> in the interleukin (IL) 21 (IL-21) gene and rheumatoid arthritis (RA) have existed.
IL-21 has the potential to activate T cells, B cells, monocytes/macrophages and synovial fibroblasts in RA pathogenesis through activation of JAK-STAT, MAPK and PI3K/Akt signaling pathways.
Expression levels of PD-1 and IL-21 in Tfh cells were higher in patients with RA than in healthy subjects, while no difference in ICOS expression was observed between patients and controls.
Stimulation of naïve RA B cells with IL-21 and CD40L resulted in an increase in differentiation into plasmablasts and an increase in IL-6 production in comparison to healthy controls, which was dose dependent on IL-21 stimulation.
Leptin-stimulated RA PBMC upregulated CD4<sup>+</sup>CXCR5<sup>+</sup>ICOS<sup>+</sup> T cells, along with increased IL-6, IL-21, and IL-12.CD4<sup>+</sup>CXCR5<sup>+</sup>ICOS<sup>+</sup> T cells, Bcl-6 mRNA expression, pSTAT1, and pSTAT3 obviously declined when anti-IL-6R antibody was added into leptin-treated RA PBMC, which suggested that leptin upregulated RA CD4<sup>+</sup>CXCR5<sup>+</sup>ICOS<sup>+</sup> T cells via increased IL-6 by activation of STAT1 and STAT3.
CD8+IL-17+, CD8+IFNγ+ and CD8+IL-17-IL-22+ T-cells were evaluated by flow-cytometry in 25 consecutive PsA patients, 7 rheumatoid arthritis (RA) patients, 16 patients with psoriasis, and 26 healthy controls (HC).
Deregulated production of interleukin (IL)-17 and IL-21 contributes to the pathogenesis of autoimmune disorders such as systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA).
We conclude that IL-22 expression level was increased and correlated with disease severity, which indicated that IL-22 may play an important role in development of PIA, and was helpful to explorer the pathogenesis of rheumatoid arthritis.