The purpose of this study is to: 1) to develop a method to quantify Epstein Barr Virus (EBV) load in lung tissue of humans and to determine whether EBV viral load is significantly higher in lung tissue from patients with idiopathic pulmonary fibrosis (IPF) than in control lung tissue; 2) to determine whether EBV localized to epithelial cells in IPF lungs and to relate epithelial positivity to tissue viral load; 3) to measure viral load in induced sputum from IPF subjects over time in order to determine whether periodic active herpes virus replication occurred in the respiratory tract; and 4) to compare longitudinal measures of viral load in induced sputum with simultaneously collected saliva in order to assess the clinical utility of the two approaches.