OP0035 EXAMINATION OF INTERSTITIAL LUNG DISEASE IN PATIENTS WITH RHEUMATOID ARTHRITIS – PREVALENCE, TIME TO ONSET, AND CLINICAL CHARACTERISTICS

Anti-protein arginine deiminase antibodies are distinctly associated with joint and lung involvement in rheumatoid arthritis

OBJECTIVES

RA is a chronic inflammatory disease in which possible interstitial lung disease (ILD) is an extra-articular manifestation that carries significant morbidity and mortality. RF and ACPA are included in the RA classification criteria but prognostic and diagnostic biomarkers for disease endotyping and RA-ILD are lacking. Anti-protein arginine deiminase antibodies (anti-PAD) are a novel class of autoantibodies identified in RA. This study aimed to assess clinical features, ACPA and anti-PAD antibodies in RA patients with articular involvement and ILD.

METHODS

We retrospectively collected joint erosions, space narrowing, clinical features and lung involvement of a cohort of 71 patients fulfilling the 2010 ACR/EULAR RA classification criteria. Serum samples from these patients were tested for ACPA IgG (QUANTA Flash CCP3), and anti-PAD3 and anti-PAD4 IgG, measured with novel assays based on a particle-based multi-analyte technology (PMAT).

RESULTS

Anti-PAD4 antibodies were significantly associated with radiographic injury (P = 0.027) and erosions (P = 0.02). Similarly, ACPA levels were associated with erosive disease (P = 0.014). Anti-PAD3/4 double-positive patients displayed more joint erosions than patients with anti-PAD4 antibodies only or negative for both (P = 0.014 and P = 0.037, respectively). RA-ILD (15.5%, 11/71 patients) was associated with older age (P < 0.001), shorter disease duration (P = 0.045) and less erosive disease (P = 0.0063). ACPA were elevated in RA-ILD, while anti-PAD4 were negatively associated (P = 0.043).

CONCLUSION

Anti-PAD4 and anti-PAD3 antibodies identify RA patients with higher radiographic injury and bone erosions. In our cohort, ILD is associated with lower radiographic and erosive damage, as well as low levels of anti-PAD4 antibodies.

Associations between shortened telomeres and rheumatoid arthritis-associated interstitial lung disease among U.S. Veterans

BACKGROUND

Shortened telomeres are associated with several different subtypes of interstitial lung disease (ILD), although studies of telomere length and ILD in rheumatoid arthritis (RA) are lacking.

METHODS

Within the Veterans Affairs Rheumatoid Arthritis (VARA) registry, we performed cross-sectional and case-control studies of prevalent and incident ILD, respectively. We randomly selected a subset of RA patients with ILD and individually matched them to RA patients without ILD according to age, sex, and VARA enrollment date. Telomere length was measured on peripheral blood leukocytes collected at registry enrollment using quantitative PCR (T/S ratio). Short telomeres were defined as a T/S ratio in the lowest 10th percentile of the cohort.

RESULTS

Our cross-sectional study cohort was comprised of 54 RA-ILD patients and 92 RA-non-ILD patients. T/S ratios significantly differed between patients with and without prevalent ILD (1.56 [IQR 1.30, 1.78] vs. 1.96 [IQR 1.65, 2.27], p < 0.001). Similarly, prevalence of ILD was significantly higher in patients with short vs. normal-length telomeres (73.3% vs. 32.8%, p = 0.002). Short telomeres were independently associated with an increased odds of prevalent ILD compared to normal-length telomeres (adjusted OR 6.60, 95% CI 1.78-24.51, p = 0.005). In our case-control analysis, comprised of 22 incident RA-ILD cases and 36 RA-non-ILD controls, short telomeres were not associated with incident RA-ILD (adjusted OR 0.90, 95% CI 0.06-13.4, p = 0.94).

CONCLUSION

Short telomeres were strongly associated with prevalent but not incident ILD among patients with RA. Additional studies are needed to better understand telomere length dynamics among RA patients with and without ILD.

Interstitial lung disease throughout the rheumatoid arthritis disease course

PURPOSE OF REVIEW

To summarize the current understanding of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) throughout the rheumatoid arthritis (RA) disease course from preclinical to established disease.

RECENT FINDINGS

ILD is a serious extra-articular manifestation of RA. Multiple studies have demonstrated a high prevalence of both subclinical and clinical ILD throughout the RA disease course. Investigations of patients without RA have demonstrated an association between RA-related autoantibodies like anticitrullinated protein antibodies (ACPA) and interstitial abnormalities on lung imaging. A significant proportion of RA-ILD patients develop ILD prior to articular manifestations, suggesting that the lung plays a central role in RA development, perhaps through ACPA production. RA-ILD also occurs in early RA, when exuberant autoantibody production and systemic inflammation may propagate pulmonary disease activity. In patients with established RA, a high burden of subclinical and clinical ILD results in significant morbidity, mortality, and healthcare expenditure. Multiple epidemiologic and genetic risk factors, as well as serum biomarkers, have been associated with RA-ILD.

SUMMARY

Subclinical and clinical ILD occur frequently in preclinical, early, and established RA and may play a key role in RA-related autoantibody production and disease progression. Further studies are needed to better understand the risk factors, prognosis, and potential therapies for RA-ILD.