A retrospective analysis of the relationship between anti-cyclic citrullinated peptide antibody and interstitial lung disease in systemic sclerosis

Abstract

Anti-cyclic citrullinated peptide antibody testing is used to diagnose rheumatoid arthritis and associated with interstitial lung disease in RA. Herein, we investigate the relationship between anti-CCP antibody and ILD in SSc. We performed a retrospective analysis at a tertiary medical center between 2005 and 2019. Patients with SSc, systemic lupus erythematosus, and polymyositis/dermatomyositis (PM/DM) were evaluated for anti-CCP antibody and ILD. Additionally, medical records of SSc patients with ILD were reviewed. SSc patients had the highest anti-CCP antibody positivity rate compared to those with SLE and PM/DM. The incidence of ILD was higher in SSc patients with anti-CCP antibody than in those without. The usual interstitial pneumonia (UIP) incidence was higher in the anti-CCP antibody-positive group than in the anti-CCP antibody-negative group. The DLCO was lower in the anti-CCP antibody-positive group than in the anti-CCP antibody-negative group. On multivariable analysis, factors associated with SSc-ILD were anti-CCP antibody or rheumatoid factor (β coefficient, 2.652 [95% CI 1.472 to 4.776]) and anti-Scl70 antibody (β coefficient, 4.011 [95% CI 2.142 to 7.508]). Anti-CCP antibody may be associated with a higher incidence of ILD in SSc. SSc patients with anti-CCP antibody may have more UIP pattern and lower DLCO.Trial Registration Retrospectively registered.

Figure 1

Representative HRCT images of patients with SSc-ILD. Axial (A) and coronal (B) HRCT images of an anti-CCP antibody-negative patient with SSc-ILD. They show extensive ground-glass opacities and traction bronchiectasis with basal predominance. These findings are typical of a non-specific interstitial pneumonia pattern. Axial (C) and coronal (D) HRCT images of an anti-CCP antibody-positive patient with SSc-ILD. They show predominant lower lobe pulmonary fibrosis and traction bronchiectasis with exuberant honeycombing sign. These findings are consistent with the usual interstitial pneumonia pattern. HRCT: high resolution computed tomography; SSc: systemic sclerosis; ILD: interstitial lung disease.