SEMA4A and rheumatoid arthritis: Recently, Sema4A was identified as a potent factor in RA in preclinical studies.460 Under stimuli by TNF-α et al., EC-derived Sema4A-Plexin-D1 signaling can promote type H angiogenesis, Th17 differentiation, and the expression of inflammatory factors in synovial cells.461,462 A trial assessing whether Sema4A can be an angiogenic biomarker in juvenile idiopathic arthritis has been conducted.