Expression of bcl-2 Protein in Bronchoalveolar Lavage Cell Populations from Patients with Idiopathic Pulmonary Fibrosis

OBJECTIVE: To investigate changes in the expression of the antiapoptotic protein bcl-2 in bronchoalveolar lavage fluid (BALF) cell populations in patients with idiopathic pulmonary fibrosis (IPF). STUDY DESIGN: Ten patients with IPF underwent fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) in the area of maximal radiographic shadowing (based on high-resolution computed tomography findings). Results were compared with those of 10 normal people in the control group. Cellular bcl-2 expression was identified using an immunoperoxidase staining method. RESULTS: A statistically significant (P <.001) increase in the expression of bcl-2 in BALF neutrophils and eosinophils was observed in patients with IPF as compared with controls. BAL macrophages exhibited only a slight (statistically insignificant) increase in bcl-2 expression in IPF patients. No bcl-2 expression was observed in BAL lymphocytes from IPF patients in contrast to the control group. CONCLUSION: The over-expression of bcl-2 on BALF neutrophils and eosinophils, cells that characterize the special cellular profile of alveolitis in IPF, could be one of the pathophysiologic mechanisms of this disease.