Rheumatoid Arthritis-Related Autoantibodies, Articular Inflammation, and RA-Associated Interstitial Lung Disease

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PROJECT SUMMARY Rheumatoid arthritis (RA) is a systemic autoimmune disease affecting nearly 1% of adults causing a painful, destructive inflammatory arthritis with serious long-term consequences including chronic pain, disability, accumulation of morbidities, and excess mortality. Patients with RA are susceptible to developing interstitial lung disease (ILD), a devastating complication with high morbidity and mortality. Rheumatoid factor (RF) and anti-cyclic citrullinated peptide (ant-CCP) autoantibodies are elevated in the serum of two-thirds of patients with RA. Seropositive RA patients are more likely to develop RA-ILD. Previous studies suggest that mucosal surfaces of the lung may be an initiating site for RA, after smoking or exposure to other inhalants, where RF, anti-CCP, and other autoantibodies may be formed years before joint symptoms develop. Aberrant post- translational modifications (PTM) to proteins may serve as neoantigens forming local inflammation in the lungs and production of autoantibodies related to PTM. This site of lung injury may later manifest clinically as RA-ILD and articular inflammation may impact risk for subclinical RA-ILD through systemic inflammation. Therefore, RA-related autoantibodies, articular inflammation, and RA-ILD may be linked throughout the disease course of RA. These investigations will study whether RA-related autoantibodies and articular inflammation predict subclinical and clinically-apparent RA-ILD. In the first aim, we will perform a nested case-control study using a derivation dataset in the Brigham RA Sequential Study (BRASS) and a replication dataset in the Partners Biobank. BRASS and the Partners Biobank are patient registries for research. We have identified RA-ILD cases as well as controls with RA but no ILD in these research registries and propose to measure clinical and PTM RA- related autoantibodies. In the second aim, we will perform a multi-site prospective observational study of patients with new-onset RA who will undergo serial measures of articular inflammation and chest high- resolution computed tomography imaging to evaluate whether the burden of articular inflammation in early RA reflects risk for subclinical RA-ILD. In the third aim, we will analyze whether smokers in COPDGene with elevation of RA-related autoantibodies without articular RA are more likely to have subclinical ILD. COPDGene is a large US nationwide observational study that has already been phenotyped for presence or absence of ILA on chest computed tomography imaging. Dr. Jeffrey Sparks (the PI) is an Assistant Professor of Medicine at Brigham and Women’s Hospital and Harvard Medical School. He is an early-stage investigator previously funded by NIAMS through K23 and R03 awards to investigate the role of the lung in RA etiology and outcomes. These proposed studies will interrogate the overarching hypothesis that RA autoimmunity, articular inflammation, and ILD are intrinsically linked across the disease course of RA (pre-RA, early RA, established RA). These studies have high potential for impactful results that will elucidate the pathogenesis of both RA and RA-ILD and may ultimately provide the evidence basis for RA-ILD screening and prevention strategies for this devastating complication.