Serum stratifin as a diagnostic and prognostic biomarker of acute exacerbation of interstitial lung disease

Abstract

Abstract Background Levels of stratifin (SFN), a member of the 14-3-3 protein family, increase in patients with drug-induced lung injury associated with diffuse alveolar damage (DAD). Therefore, we investigated its suitability as a biomarker of acute exacerbation (AE) of interstitial lung disease (ILD). Methods Thirty-two patients with clinically stable ILD (CS-ILD) and 22 with AE-ILD were examined to assess whether their serum SFN level was an effective biomarker of AE-ILD and whether its levels could predict prognosis in AE-ILD by analysing the survival rates at 90 days and 1 year after AE-ILD. Results Serum SFN levels were higher in the AE-ILD group than in the CS-ILD group (8.4 ± 7.6 vs. 1.3 ± 1.2 ng/mL, p < 0.001). SFN levels increased in patients who died within 90 days and 1 year compared with in patients who survived beyond these time points (13.5 ± 8.7 vs. 5.6 ± 5.3 ng/mL, p = 0.011 and 13.1 ± 7.5 vs. 3.1 ± 1.9 ng/mL, respectively; p < 0.001) in the AE-ILD group. The cut-off value for predicting the 90-day and 1-year survival was 6.6 ng/mL. The 90-day and 1-year survival rates were significantly better in the population below the cut-off value than in those above the cut-off value (p = 0.0017 vs. p < 0.0001). Conclusions Serum SFN level was higher in patients with AE-ILD than in those with CS-ILD and could serve as a biomarker for predicting the 90-day and 1-year survival rates in patients with AE-ILD.