MDK and pulmonary fibrosis: 1997; Maruyama et al. 2004; Krzystek‐Korpacka et al. 2010, 2011). Our present study results, generated in IPF patients, similarly suggest the importance of midkine in pulmonary inflammation. There is a considerable debate regarding the role of inflammation in lung fibrosis, especially in IPF (Gross and Hunninghake 2001; Fujimoto et al. 2015). However, an increase in inflammatory cells such as neutrophils in the BAL fluid was reported to be a predictive factor for a poor prognosis for IPF (Rudd et al. 1981; Xaubet et al. 1998) and scleroderma lung disease (Behr et al. 1996).