Neuromyelitis optica spectrum disorder occurred after interferon alpha therapy in malignant melanoma

Background: Several cases of neuromyelitis optica spectrum disorder (NMOSD) caused by interferon alpha (IFN-alpha) treatment in hepatitis C were reported in past literatures, but NMOSD resulted from IFN-alpha treatment in tumor has not yet been reported previously. Methods: A unique case of NMOSD caused by IFN-alpha therapy in malignant melanoma is presented. Related cases about NMOSD caused by IFN-alpha therapy on Pubmed were reviewed further. Results: A 40-year-old Chinese woman was diagnosed as right breast skin malignant melanoma and received melanoma resection in April 2012, then underwent IFN-alpha-2b therapy (5 million IU every time, 3 times/week) from May 2012 to Sep 2016. In December 2016, the patient developed bilateral optic neuritis, with no light perception at her worst. After a month-long glucocorticoid treatment, she could see finger movement from 40 cm. Serum positive anti-AQP-4 antibody was found by enzyme-linked immunosorbent assay (ELISA, 75.9 u/ml) in Feb 2017 and indirect immunofluorescence testing (IIFT, 1:320) in Sep 2017. Methylprednisolone (8 mg/day) and rituximab (0.1 g/every 6 months) were used for prevention. On the follow up visit in Jan 2019, she could see finger movement from 1 m, and no melanoma and NMOSD relapse were complained. Literature review only found 3 cases of NMOSD caused by IFN-alpha treatment in hepatitis. Conclusions: A unique case of NMOSD with positive anti-AQP-4 antibody after IFN-alpha treatment in malignant melanoma was reported. Type I IFNs may be pro-inflammatory in NMOSD and this possible consequence of IFNs use should be cautioned in future practice.