Soluble intercellular adhesion molecule-1 for stable and acute phases of idiopathic pulmonary fibrosis

The levels of soluble intercellular adhesion molecule-1 (sICAM-1) have been reported to increase in patients with idiopathic pulmonary fibrosis. However, the utility of sICAM-1 has not been reported in detail. The aim of this study was to investigate whether sICAM-1 was a useful biomarker for stable idiopathic pulmonary fibrosis (IPF) and early phase of acute exacerbation of IPF. The patients who were diagnosed with IPF between 2013 and 2015 were enrolled. The levels of sICAM-1 and other interstitial pneumonia markers were measured. In this study, 30 patients with stable IPF and 11 patients with acute exacerbation of IPF were collected. Mean sICAM-1 levels were 434 ± 139 ng/mL for the stable phase of IPF, 645 ± 247 ng/mL for early phase of acute exacerbation of IPF, 534 ± 223 ng/mL for connective tissue disease-associated interstitial pneumonia, 221 ± 42 for chronic obstructive pulmonary disease, and 150 ± 32 ng/mL in healthy volunteers. For the stable phase of IPF, sICAM-1 levels correlated with Krebs von den Lungen-6 (KL-6) (r value: 0.41; p value: 0.036). Mean sICAM-1 levels were significantly higher in patients with early phase of acute exacerbation of IPF than with stable phase of IPF (p = 0.0199). Multiple logistic analyses indicated that the predictors for early phase of acute exacerbation of IPF were only sICAM-1 and C-reactive protein (odds ratio: 1.0093; 1.6069). In patients with stable IPF, sICAM-1 levels correlated with KL-6; sICAM-1 might be a predictive indicator for prognosis. In the early phase of acute exacerbation of IPF, sICAM-1 might be more useful for diagnosis than other interstitial pneumonia markers.