SESSION TITLE: Biomarkers in ILD
SESSION TYPE: Original Investigation Slide
PRESENTED ON: Tuesday, October 29, 2013 at 04:30 PM - 05:30 PM
PURPOSE: Interstitial lung diseases (ILDs) are illnesses characterized by multifocal inflammation and fibrosis in the lungs that can lead to progressive decline in lung function and death. The rate of progression of ILDs is unpredictable and the development of a biomarker that could predict disease progression would be valuable clinically. Fibrocytes are circulating bone marrow-derived cells that home to injured tissues and mediate scar formation. Fibrocytes have been implicated in lung fibrosis in animal models of ILD and are elevated in the peripheral blood in human ILD, raising the possibility that they may serve as a biomarker of disease activity. We sought to assess whether, in a population of individuals destined to develop ILD, peripheral blood fibrocyte counts correlate with lung fibrosis. Hermansky-Pudlak syndrome (HPS) is an autosomal-recessive disease that results in albinism and uniform development of progressive interstitial lung disease as middle-aged adults.
METHODS: We measured circulating fibrocyte counts by flow cytometry in a cohort of subjects with HPS and healthy control subjects, and correlated the results to evidence of ILD on PFTs and CT scans.
RESULTS: In a pilot study, we compared 5 subjects with HPS and clinically evident ILD, 3 subjects with HPS and no ILD, and 7 healthy control subjects. There was no significant difference between the HPS without pulmonary fibrosis and control groups. In contrast, the HPS group with pulmonary fibrosis group had approximately 10-fold elevation of peripheral fibrocytes compared to controls.
CONCLUSIONS: These data suggest that measurement of fibrocytes may be a suitable biomarker for disease activity in patients with ILD. We are in the process of assessing fibrocytes longitudinally in a larger cohort of HPS subjects, testing the hypothesis that the number and/or phenotype of circulating fibrocytes predicts the subsequent development and progression of ILD.
CLINICAL IMPLICATIONS: If circulating fibrocyte counts are found to predict subsequent development of ILD in subjects with Hermansky-Pudlak syndrome, they may be useful as a biomarker of lung disease in these individuals. More broadly, such a finding would provide evidence of a biomarker of disease activity that is predictive of future deterioration in patients with interstitial lung diseases.
DISCLOSURE: The following authors have nothing to disclose: Aaron Trimble, Marie Burdick, Roxanne Fischer, William Gahl, Bernadette Gochuico, Borna Mehrad
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