Serum analysis of coagulation factors in IPF and NSIP.

Recent literature and our previous proteomic findings prompted us to study the coagulation system in idiopathic pulmonary fibrosis (IPF), the pathogenesis of which remains unclear. The aim of this study was to compare coagulation factors in idiopathic pulmonary fibrosis and idiopathic nonspecific interstitial pneumonia (NSIP) patients and healthy controls. Thirty-three IPF patients (23 acute exacerbation and 10 stable IPF patients), 7 NSIP patients, and 44 controls were enrolled. Concentrations of D-dimer, homocysteine, functional protein C, protein C antigen, free and total protein S antigen and activity, fibrinogen and factor VIIIc were analyzed in serum of patients and controls. The lupus anticoagulant (LAC) test was also performed. Factor VIIIc levels were significantly higher in acute exacerbation IPF patients than controls (p = 0.0001) and in stable IPF patients than controls (p = 0.002). Factor VIIIc levels were higher and PT levels were lower in acute exacerbation IPF patients who died after exacerbation than in patients who survived (p = 0.04 and p = 0.003, respectively). D-dimer, fibrinogen, and homocysteine levels were also significantly higher in IPF patients than controls (p < 0.01). Protein C activity was increased in acute exacerbation IPF patients than controls (p = 0.005). The LAC test was positive in seven IPF patients and negative in controls. Procoagulant status was demonstrated in IPF patients (mainly in acute exacerbation/IPF) than controls and NSIP patients, probably due to endothelial activation and microvascular injury. These preliminary results are of interest because of their potential implications in the pathogenesis and treatment of this disease.