Usual interstitial pneumonia (UIP) in rheumatoid arthritis. Axial computed tomography (CT) scan of the chest of a 47-year-old female patient with pulmonary fibrosis (scarring) caused by usual interstitial pneumonia, a symptom of rheumatoid arthritis. Scarring has given the lobes of the lungs (dark grey) a honeycomb appearance in places, with areas of bronchiectasis (enlargement of the airways). The heart is centre right. UIP causes scarring in the supporting framework (interstitium) of the lung, and results in progressive shortness of breath and coughing. Rheumatoid arthritis is an autoimmune disease where the immune system attacks the bodys cells, and primarily affects the joints.