P239 Diagnostic Potential of MMP-1 and SP-A As Biomarkers to Distinguish Chronic Hypersensitivity Pneumonitis from Idiopathic Pulmonary Fibrosis

Introduction: Hypersensitivity pneumonitis (HP) is an inflammatory interstitial lung disease caused by a wide variety of organic particles. In general, the diagnosis of chronic HP represents a challenge for clinicians that need to use a constellation of clinical, laboratory, radiographic and pathological data to assess a confident diagnosis. Importantly, the clinical features cHP can be indistinguishable from those observed in idiopathic pulmonary fibrosis (IPF). Objective: To determine whether serum levels of surfactant protein A (SP-A) and matrix metalloprotease-1 (MMP-1) may help to differentiate cHP from IPF. Methods: This was a cross-sectional study including patients with IPF (n = 31), cHP (n = 31) and 17 healthy subjects. SP-A and MMP-1 serum levels were determined by ELISA and were evaluated for the differential diagnosis between HP and IPF, and also correlated with values of pulmonary function tests at diagnosis. Results: MMP-1 and SP-A were significantly elevated in cHP compared with the other two groups. MMP-1 (HP= 11.7 ± 14 ng/ml versus FPI= 16 ± 20.7 ng/ml, p< 0.001) and versus Controls= (0.4 ± 0.3 ng/ml, p < 0.0001), ANOVA between groups < 0.0001. SP-A (HP= 74 ± 30 pg/ml versus FPI= 54 ± 20 pg/ml, p< 0.02) and versus Controls= (35 ± 6 pg/ml, p < 0.0001), ANOVA between groups < 0.0001. There was no correlation between MMP-1 or SP-A levels with the abnormalities in pulmonary function tests. Conclusions: Our findings indicate that patients with cHP display the highest concentration of MMP-1 and SP-A which may be useful biomarkers to distinguish it from IPF.