Cytokine Target cells Function IL-17A/F neutrophil, macrophage, endothelial cell osteoclast synoviocyte Recruitment to site of inflammation, activation, and migration Promotion of osteoclastogenesis Induction of proinflammatory cytokine IL-22 keratinocyte synoviocyte synovial fibroblast Induction of β-defensins, promotion of epidermal hyperplasia Proliferation Induction of RANKL, promotion of osteoclastogenesis IL-21 B cell T cell CD4 T cells and fibroblast-like synoviocyte Antibody class switching Autoreactive B cell maturation Tfhdevelopment RANKL induction

Table 1: Th17 cytokines and their relation to arthritis pathology.