Human epididymis secretory protein 4 in idiopathic inflammatory myopathy-associated interstitial lung disease

Objective The current study assessed the level of serum HE4 in patients with IIM to evaluate its feasibility in diagnosing IIM-ILD, as well as determined the association between HE4 and demographic, clinical, and laboratory characteristics of IIM patients. Methods Sera and clinical data were collected from 139 patients with IIMs and 135 healthy controls. We compared the clinical parameters between the high and low HE4 groups, and the relationship between HE4 levels and clinical parameters was determined. Moreover, the expression of HE4 in the lung tissue was accessed. Results HE4 level was significantly higher in the serum of IIM patients than in the controls (median 69.3 versus 33.5 mu g/L, P < 0.001). Patients in the high HE4 group had higher ferritin (median 559 versus 83.7 mu g/L, P = 0.006), frequencies of ILD(94.4% versus 56.1%, P < 0.001) and anti-Jo-1 autoantibodies (25.5% versus 5.7%, P = 0.018) compared with the low HE4 group. The immunohistochemical staining of HE4 in lung tissues was positive in IIM-ILD and negative in controls. Conclusion Our findings suggested that serum HE4 might be a clinically useful biomarker for IIM-ILD.