COMPARATIVE CLINICAL, LABORATORY, AND INSTRUMENTAL EVALUATION OF INTERSTITIAL LUNG CHANGES IN RHEUMATOID ARTHRITIS

Abstract

Interstitial lung disease (ILD) is a common extra-articular manifestation of rheumatoid arthritis (RA). Objective: to study the associations of the data of high-resolution computed tomography (HRCT) and the esti- mate of diffusing lung capacity (DLC) with clinical and laboratory parameters in RA patients with and without ILD. Subjects and methods. 79 RA patients fulfilling the 1987 American College of Rheumatology criteria (61 women and 18 men) admitted to the Nasonova Research Institute of Rheumatology were included. Results. HRCT revealed signs of ILD in 58 (73%) cases. The patients with ILD were divided into three groups: 1) 18 (31%) patients with ground glass opacities; 2) 34 (58.6%) patients with fibrosis; 3) 6 (10.4%) patients with the honeycomb lung. Twenty-one (27%) patients with ILD were included in Group 4. In the ILD patients with ground glass opacities, the levels of anti-cyclic citrullinated peptide (ACCP) antibodies and rheumatoid factor (RF) were much above those in the patients without ILD (240 [166; 410.5], 480 [140; 850.5] and 73 [31; 101], 330,5 [118.5; 604.8], respectively). In the patients with ILD, the concentration of C-reactive protein (CRP) (46 [35; 91]) was higher than that in those without ILD (24 [18; 31]; p < 0.05). In the ILD patients with ground glass opacities, DLC was considerably below that in those with ILD – 59.2±11.2 and 79.8±12.1% of the normal value, respectively (p < 0.001). Conclusion. The associations found between ACCP antibodies and DLC, DAS28 and DLC may suggest that ACCP antibodies are implicated in the pathogenesis of ILD and the lung is involved in the immunoinflammatory process. The high percent of smokers detected in our investigation confirms the considerable role of smoking in the pathogene- sis of RA-associated ILD. In the RA patients with ILD, ground glass opacities must be an indicator of the activity of an immunopathological process in the lung.

Keywords

• rheumatoid arthritis
• high-resolution computed tomography
• diffusing lung capacity
• anti-cyclic citrulli- nated peptide antibodies
• rheumatoid factor
• c-reactive protein
• smoking.