Table 1.
Inflammatory cytokines in PsA.
| Cytokine | Main Source | Function in PsA |
|---|---|---|
| TNF-α | Macrophages, T cells, NK cells, mast cells | Elevation in the levels of cytokines, chemokines, matrix metalloproteinases, and adhesion molecules from various immune cells Induction of osteoclasts to promote the degradation of cartilage and bone |
| IL-23 | Dendritic cells, macrophages | Promotion of Th17 cell differentiation and GM-CSF production |
| IL-12 | Dendritic cells, macrophages | Promotion of Th1 cell differentiation through STAT4 |
| IL-17A/F | Th17 cells, NK cells, type 3 innate lymphoid cells | Stimulation of fibroblast-like synoviocytes, chondrocytes, and osteoclasts Elevation in the levels of pro-inflammatory cytokines and matrix metalloproteinases Induction of neutrophil recruitment |
| IL-21 | T cells, NK cells | Promotion of T cell differentiation (specifically, into Th17 cells) |
| IL-22 | T cells, innate lymphoid cells | Activation of fibroblast-like synoviocytes Promotion of osteoclast and bone degradation |
| IL-32 | NK cells, T cells, monocytes, epithelial cells | Potentiation of inflammation through the activation of NF-κB signaling and promotion of osteoclast differentiation |
| IL-33 | Macrophages, dendritic cells, mast cells, epithelial cells | Activation of Th1/Th17-mediated inflammation |
| IFN γ | Th1 cells, type 1 innate lymphoid cells, NK cells | Activation of macrophage and T cell Promotion of RANKL secretion |
| GM-CSF | Macrophages, T cells, synovial fibroblasts | Recruitment of various immune cells |
| IL-9 | Th9 cells | Promotion of Th17-associated inflammation and IL-17A production |
| IL-6 | Macrophages, T cells, endothelial cells | Stimulation of STAT3 signaling to increase the production of pro-inflammatory cytokines |
| IL-15 | Macrophages | Promotion of T cell proliferation; natural killer cell activation; and production of IFN-γ, TNF-α, and IL-17 |
| IL-1α | Macrophages, dendritic cells | Induction of IL-17, IL-21, and IL-22 expression by γδT cells in combination with IL-23 |
GM-CSF: granulocyte-macrophage colony-stimulating factor; IFN: interferon; IL: interleukin; RANKL: receptor activator of nuclear factors’ κB ligand; STAT: signal transducer and activator of transcription; TNF: tumor necrosis factor.