Propionibacterium acnes-associated Sarcoidosis Possibly Initially Triggered by Interferon-alpha Therapy.

A 46-year-old woman with uveitis was referred to our respiratory diseases department in July 2018. Her medical history included transient bilateral hilar mediastinal lymphadenopathy (BHL) and multiple pulmonary nodules in May 2013 during pegylated interferon-alpha and ribavirin treatment for chronic hepatitis C infection. Five years post-treatment, chest X-ray revealed BHL and nodular recurrence. A biopsy of the subcutaneous buttock nodules revealed scattered non-caseating epithelioid granulomas with positive PAB immunohistochemical staining. This seem to be the first report of Propionibacterium acnes-associated sarcoidosis possibly initially triggered by interferon-alpha therapy. Understanding the mechanisms underlying interferon-triggered P. acnes-associated sarcoidosis may clarify the sarcoidosis immunopathogenesis.