CHIT1 and pulmonary fibrosis: High resolution CT evidence of lung fibrosis with reticular abnormalities and traction bronchiectasis (group 4) (n=12) was associated with significantly higher chitotriosidase activity than in patients with no evidence of lung involvement (q=4.654; p<0.001) or with only parenchymal micronodules and lymph node enlargement (q=4.286; p<0.01) or with parenchymal micro- and macro-nodules associated with consolidation (q=5.828; p<0.0001).