Serum levels of AREG and HB-EGF, and correlation with CK and KL-6 serum levels in patients with IIM. (A) Serum AREG (left) and HB-EGF (right) levels in HC and IIM patients with and without ILD. (B) Serum AREG (left) and HB-EGF (right) levels in HC, IIM patients with normal CK levels, and IIM patients with elevated CK levels. Elevated CK levels were defined as those exceeding the upper limits of the normal range of CK values (248 U/L and 153 U/L for males and females, respectively). (C) Correlation between CK levels and serum AREG in patients with IIM (left), correlation between KL-6/%VC levels and serum AREG in IIM patients with ILD (middle and right). (D) Correlation between CK levels and serum HB-EGF in patients with IIM (left), correlation between KL-6/%VC levels and serum HB-EGF in IIM patients with ILD (middle and right). * p <0.05, *** p <0.001.