Table 2.

Similarities and differences between the K/BxN STA and RA models.

Feature	K/BxN STA model	RA
Histopathological manifestations	• Leukocyte invasion • Synovitis • Pannus formation • Cartilage and bone destruction • Joint remodeling (4)	• Leukocyte invasion • Synovitis • Pannus formation • Cartilage and bone destruction • Joint remodeling (4)
Autoantibodies	Main driver (9)	Present – role unknown (122)
Specificity of autoantibodies	G6PI (2)	• G6PI • Citrullinated filaggrin • Fc portion of IgG (rheumatoid factor) • Keratin • Chondrocyte gp39 • Heat-shock protein • Collagen II (123)
Important immune cells	• Neutrophils (25) • Macrophages (41) • Mast cells? (45, 46)	• Neutrophils • Macrophages • CD4 T cells • B cells • Dendritic cells (55)
Pro-inflammatory cytokines	• TNF (57) • IL-1β (57) • GM-CSF (43) • G-CSF (39) • MIF (83, 84) • IL-17? (62, 63)	• TNF (55) • IL-6 (55) • GM-CSF (44)
Pain	Present and persists after resolution of inflammation (87)	Present and persists after resolutionof joint swelling with anti-inflammatory treatment (85)
Common therapies	• NSAIDs (65) • TNF blockade (57) • Glucocorticoids (128, 129) • Methotrexate (130) • Tacrolimus (131)	• NSAIDs • TNF blockade • Glucocorticoids • Methotrexate • Tacrolimus (66)