Early detection of interstitial pneumonia by monitoring KL‐6 in a chronic hepatitis C patient undergoing pegylated interferon and ribavirin therapy

A 58‐year‐old woman with chronic hepatitis C developed interstitial pneumonia (IP) while undergoing pegylated interferon (PEG IFN)‐α‐2a and ribavirin (RBV) therapy. Serum levels of sialylated carbohydrate antigen KL‐6 (KL‐6), a known marker of disease activity in fibrosing lung disorders, had been regularly measured once a month for early detection of IP, and had begun rising noticeably from 12 weeks to 540 U/mL at 33 weeks of treatment. On examination, remarkable fine crackles were detected by dorsal auscultation and bilateral ground‐glass opacities and reticular shadows were depicted by computed tomography. The patient successfully recovered from her early‐stage pneumonia by immediate discontinuation of therapy, which indicates that regular monitoring of serum KL‐6 may be effective for avoidance of IP progression induced by PEG IFN and RBV therapy.