Identification of shared citrullinated immunological targets in the lungs and joints of patients with rheumatoid arthritis

Insights from populations at risk for the future development of classified rheumatoid arthritis

Rheumatoid arthritis (RA) develops through a series of stages. In the seropositive subset of classified RA patients, a preclinical stage is present for years before the onset of clinically apparent disease. Relevant preclinical biomarkers include autoantibodies, alterations of lymphoid populations, elevated cytokines/chemokines, genetic/genomic factors, imaging studies, clinical findings, dietary and environmental biomarkers, cardiovascular disease risk assessment, microbiome analyses, and metabolomic changes. Identifying the population of asymptomatic subjects at sufficiently high risk for disease to be informative and representative of "preclinical patients" is a challenge. This article reviews the results of analyses that have been undertaken in these "at-risk" subjects.

Autoimmunity to citrullinated proteins and the initiation of rheumatoid arthritis

Clinical manifestations of rheumatoid arthritis (RA), the second most common human autoimmune disease, are primarily focused on the joints, causing disability and requiring life-long treatment to ameliorate signs and symptoms. The etiology of RA is unknown; however, important discoveries in two areas have been made which provide hope that the causal mechanisms can be identified. First, the most severe form of this disease is associated with the presence of humoral and cellular autoimmunity to citrullinated proteins and peptides. Second, in the natural history of RA, autoimmunity to citrullinated antigens appears years before the onset of clinically apparent disease. Herein is described a model in which to consider how these two features are linked during very early disease development.

Targeting interleukin-17 in patients with active rheumatoid arthritis: rationale and clinical potential

Clinical and experimental evidence suggest that interleukin-17A (IL-17A; also known as IL-17) is an attractive therapeutic target in rheumatoid arthritis (RA). Rheumatoid synovial tissue produces IL-17A, which causes cartilage and bone degradation in synovial and bone explants. Overexpression of IL-17A induces synovial inflammation and joint destruction in animal RA models. These effects are attenuated in IL-17A-deficient animals and by agents that block IL-17A. Serum IL-17A levels and, to a greater extent, synovial fluid IL-17A levels are elevated in many patients with RA. In some RA cohorts, higher IL-17A levels have been associated with a more severe clinical course. Several IL-17A blockers, including the anti-IL-17A monoclonal antibodies secukinumab and ixekizumab, and the anti-IL-17 receptor subunit A monoclonal antibody brodalumab have been evaluated in phase II clinical trials. Of these, secukinumab is the most advanced with respect to clinical evaluation in RA, with phase III trials ongoing in patients on background methotrexate who had inadequate responses to previous tumor necrosis factor blocker therapy.