The effects of a fully human SEMA5A blocking monoclonal antibody (SYD12-12), evaluated in a collagen-induced arthritis mouse model, showed that SYD12-12 alleviated inflammatory cell infiltration, synovial hyperplasia, and bone destruction, and decreased serum levels of inflammatory cytokines, such as IL-1β, IL-6, TNF-α, and IL-17A38. The gene discussed is SEMA5A; the disease is Arthritis.