Serum metalloproteinases 1 and 7 in the diagnosis of idiopathic pulmonary fibrosis and other interstitial pneumonias.

INTRODUCTION: Accurate diagnosis of idiopathic pulmonary fibrosis (IPF) has important therapeutic and prognostic implications and would be greatly aided by reliable diagnostic biomarkers as IPF has sometimes overlapping features with other interstitial lung diseases (ILD). OBJECTIVES: To explore the value of serum metalloproteinases (MMP) 1 and 7 levels in the differential diagnosis of IPF with other ILD. METHODS: MMP-1/7 serum levels were measured using Luminex xMAP technology in 139 patients- 47 IPF, 36 non-IPF Usual Interstitial Pneumonia (UIP), 14 idiopathic Nonspecific Interstitial Pneumonia (iNSIP), 29 secondary NSIP (secNSIP), 13 stage IV sarcoidosis- and 20 healthy controls, and compared using the Mann-Whitney U test. RESULTS: MMP-1 was significantly higher in IPF than non-IPF UIP (P = .042) and sarcoidosis (P = .027). MMP-7 was significantly higher in IPF than controls (P < .001), non-IPF UIP (P = .003), secNSIP (P < .001), and sarcoidosis (P < .001). The Area Under the Curve for IPF versus other ILD was 0.63 (95%CI, 0.53-0.73) for MMP-1, 0.73 (95%CI, 0.65-0.81) for MMP-7, and 0.74 (95%CI, 0.66-0.82) for MMP-1/MMP-7 combined. Sensitivity and specificity for MMP-7 cutoff = 3.91 ng/mL was 72.3% and 66.3%, respectively, Positive Predictive Values = 52.3% and Negative Predictive Values = 82.4%. CONCLUSIONS: MMP-1 and particularly MMP-7 serum levels were significantly higher in IPF than in non-IPF UIP, the main entity in differential diagnosis. The value of these biomarkers as additional tools in a multidisciplinary approach to IPF diagnosis needs to be considered and further explored.

Nonspecific interstitial pneumonia (NSIP) associated with anti-KS antibody: differentiation from idiopathic NSIP.

We report two cases of biopsy-proven nonspecific interstitial pneumonia (NSIP) with anti-KS (asparaginyl-tRNA) antibody. Anti-KS antibody is the sixth anti-aminoacyl-tRNA synthetase (ARS) antibody. They showed interstitial pneumonia without clinical symptoms, and high resolution computed tomography (HRCT) of the chest demonstrated consolidation along bronchovascular bundles and volume loss in the bilateral lower lobes, which were suggestive of connective tissue diseases (CTD). One case of cellular NSIP responded to corticosteroid, but the other case of fibrotic NSIP required corticosteroid and cyclosporin. In patients with these HRCT findings, the measurement of anti-ARS antibodies could be helpful even in the absence of clinical symptoms suggestive of CTD.