Fig. 5

Therapeutic Target. Biologic DMARDs function as antibodies that bind to external targets like circulating cytokines or cell surface receptors: TNF is a key player in the pathogenesis of RA and is the target of five biologic medications: adalimumab, certolizumab pegol, etanercept, golimumab, and infliximab. Recombinant human IL-1Ra, also known as anakinra, inhibits the biological effects of IL-1. Tocilizumab, a humanized anti-IL-6 receptor monoclonal antibody, binds to the membrane-bound and soluble forms of the IL-6 receptor and inhibits IL-6 for binding to its receptor. Rituximab is a chimeric monoclonal anti-CD20 antibody that decreases the number of B—lymphocytes. Abatacept is a fusion protein of the hinge, CH2, and CH3 domains of IgG1 and the recombinant, dimerized cytotoxic T-lymphocyte antigen 4 (CTLA-4), a natural inhibitor of T-cell activation. Abatacept prevents T-cell co-stimulation by blocking the interaction between CD28 on a T cell and B7 on an antigen presenting cell. Granulocyte macrophage colony-stimulating factor (GM-CSF), which signals via the JAK-STAT pathway and induces the production of interleukin-6 and other proinflammatory cytokines, has been approached as a therapeutic target in chronic autoimmune disease trials such as rheumatoid arthritis. DMARDs Disease-modifying antirheumatic drugs, TNF tumor-necrosis factor, RA rheumatoid arthritis, IL-1Ra interleukin-1 receptor antagonist, IgG immunoglobulin G