Seroprevalence in Rheumatoid Arthritis Patients with Interstitial Lung Disease.

Background: Rheumatoid arthritis (RA) is complicated with interstitial lung disease (ILD). Gastroesophageal reflux disease is prevented by infection and is a predisposing factor for idiopathic pulmonary fibrosis. However, the prevalence of infection in RA patients with ILD has not been sufficiently investigated.

Objective: In this study, we analyzed anti- antibodies in RA patients with ILD.

Design: Case-control observational study.

Methods: Anti- antibodies were analyzed in the sera of RA patients using a commercially available enzyme-linked immunosorbent assay kit.

Results: The positivity of anti- antibodies in RA with ILD ( = 30 [18.0%],  = .0227), usual interstitial pneumonia ( = 10 [14.3%],  = .0212), and airway disease ( = 30 [18.0%],  = .0227) was significantly lower than that of RA without chronic lung disease ( = 78 [27.5%]). The positivity of anti- antibodies was also lower in RA with chronic lung disease ( = 68 [18.2%],  = .0059). Multiple logistic regression analyses showed that the presence of anti- antibodies was independently and protectively associated with chronic lung disease in RA.

Conclusion: The seroprevalence of was lower in RA with ILD. infection prevented ILD in patients with RA by protecting them from gastroesophageal reflux disease.