Abstract
Objective. Interstitial lung disease (ILD) is involved in polymyositis/dermatomyositis (PM/DM), a disease associated with poor prognoses. Chitinase-3-like-1 protein (YKL-40) has pleiotropic biological activities involved in inflammation, cell proliferation, and tissue remodeling; however, the clinical application of YKL-40 remains limited. We investigated the clinical significance of YKL-40 in PM/DM–ILD.
Methods. Sixty-nine consecutive patients with PM/DM–ILD and 34 healthy controls were analyzed. We measured baseline and followup serum YKL-40 using an ELISA, evaluated the association of YKL-40 with clinical variables and survival, and examined YKL-40 expression in lung specimens from patients with PM/DM–ILD using immunohistochemistry.
Results. Serum YKL-40 levels were significantly greater in patients with PM/DM–ILD compared with healthy controls (p < 0.0001). Serum YKL-40 was correlated with arterial oxygen pressure (r = –0.40, p < 0.001) and percent-predicted DLCO (r = –0.41, p = 0.01) in patients with PM/DM–ILD. Multivariate Cox hazard analysis demonstrated that higher serum YKL-40 and lower percent-predicted forced vital capacity were independently associated with a poor prognosis. Immunohistochemistry analysis demonstrated that YKL-40 expression was enhanced in aggregated intraalveolar macrophages and hyperproliferative alveolar epithelial cells in patients with PM/DM–ILD.
Conclusion. YKL-40 is a promising biomarker for evaluating PM/DM–ILD activity/severity and predicting disease prognosis. Insights into YKL-40 might help elucidate the pathogenesis of PM/DM–ILD.
- CHITINASE-3-LIKE-1 PROTEIN
- POLYMYOSITIS
- DERMATOMYOSITIS
- INTERSTITIAL PNEUMONIA
- INTERSTITIAL LUNG DISEASE
- Accepted for publication May 13, 2017.