Description

Rheumatoid arthritis (RA) is one of the most common connective tissue diseases (CTD). Its prevalence is increasing worldwide . It is responsible for a considerable number of hospital visits in Egyptian Hospitals . Pumlonary involvement is common in rheumatoid arthritis (RA). Interstitial lung disease associated rheumatoid arthritis (ILD-RA) is responsible for significant morbidity and mortality .

Krebs von den Lungen 6 (KL-6) is a mucin like glycoprotein that is found mainly on the surface of type II pneumocytes as well as in bronchiolar epithelial cells . It has chemotactic and anti-apoptotic action on fibroblasts , hence, it is considered as a marker of pulmonary epithelial cell injury .

Krebs von den Lungen-6 (KL6) has been found to be a valuable diagnostic tool in many interstitial lung diseases. KL6 was found to be a valuable prognostic marker, as well as a marker for disease severity in idiopathic pulmonary fibrosis (IPF) . KL6 was found useful as well in predicting in-hospital mortality in patients with Acute exacerbation of interstitial lung disease (AE-ILD) . KL-6 serum level can serve as a diagnostic marker for connective tissue disease-associated interstitial lung disease (CTD-ILD). It can be used to monitor effectiveness of medical treatment and patient response to pulse therapy . Its value in Rheumatoid Arthritis-associated Interstitial Lung Disease (RA-ILD) has not yet been adequately investigated.