Background Connective tissue diseases (CTD) are known to have variable clinical symptoms and progression at multiple organ. Above all, the lung involvement of CTD shows the worst clinical course. The causes of CTD have not been well understood, and in most cases, the diagnosis of CTD requires diverse clinical, pathological, and imaging tests. So, the role of anti-nuclear antibodies (ANAs) in the diagnosis of CTD has been more important, especially in the cases of interstitial lung diseases (ILD), the cause of which is not obvious. In a study of ILD, which was conducted in Korea, ANA was positive in 66.1% of ILD patients. These findings suggest that ANA could be related with ILD or other lung diseases.
Objectives We conducted a retrospective study, in which the object was to assess the percentage of lung disease in ANA positive patients.
Methods We retrospectively reviewed 558 patients with ANA positive from a single tertiary center in Korea between 2011 and 2013.
Results Among 588 ANA positive patients, 145 patients were associated with lung disease (24.7%). The lung disease of 35 patients were diagnosed with ILD (24.1%), 8 patients were lung cancer (5.5%), 6 patients were pneumonia (4.1%), and 5 patients were pulmonary tuberculosis (3.4%).
Conclusions In our study, a substantial proportion of patients with ANA positive were found to have variable lung diseases. ILD was most common, and was diagnosed in 24.1% of ANA positive patients, but we found that lung cancer, pneumonia, and pulmonary tuberculosis could be diagnosed in ANA positive patients. Our findings suggest that the ANA could be positive in variable lung disease, and more specific, but not yet detected antibodies might be related with lung diseases.
Disclosure of Interest None declared