Tumour markers in rheumatoid arthritis-associated interstitial lung disease.

Interstitial lung disease (ILD) is the most common pulmonary extra-articular manifestations of rheumatoid arthritis (RA), but the pathogenesis of RA-ILD is unknown. The purpose of this study was to investigate the tumour markers levels in patients of rheumatoid arthritis-associated interstitial lung disease (RA-ILD) and to explore the diagnostic value of serum tumour markers for RA-ILD.Twenty-eight patients with RA-ILD and 83 patients with RA only were included. Serum levels of tumour markers carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 15-3, CA125, and CA19-9 were measured.Tumour markers CA15-3, CA125 and CA19-9 were increased in RA-ILD patients compared with RA without ILD patients. Logistic regression analysis revealed that older age (OR=1.06, 95% CI=[1.02-1.11]) and higher CA125 (OR=1.03, 95% CI=[1.01-1.05]) related to the increased risk of RA-ILD. ROC curve analysis showed the relationship between CA125 and RA-ILD was moderate (area under ROC curve (AUC)=0.78, 95% CI=[0.68-0.88]). In addition, CA125 levels above the normal reference (<35 U/ml) raised the risk of RA-ILD (OR=6.00, 95% CI=[2.37-15.16]).RA patient with older age and elevated tumour markers especially CA125 levels should be evaluated to check whether there is a potential of ILD.