Multiple sclerosis (MS) is an unpredictable, immune-mediated process in which an abnormal response of the body’s immune system is directed against the central nervous system (CNS), which is made up of the brain, spinal cord and optic nerves. The findings in this study suggest that anti-IL6 therapy might have future prospects for the treatment Neuromyelitis Optica Spectrum Disorder (NMOSD).

Interleukin-6 (IL6) blockage is a treatment strategy used in many inflammatory conditions. Trials in Neuromyelitis Optica Spectrum Disorder (NMOSD) are ongoing. Secondary auto-immunity affecting the central nervous system (CNS) is well described with some biologic agents, mainly tumor necrosis factor (TNF)-alpha inhibitors. These treatments can also aggravate patients with known multiple sclerosis (MS). To describe a case of a patient who developed MS using another biologic, IL6 receptor antibody Tocilizumab.

A 48-year-old woman developed MS while on treatment with Tocilizumab for Rheumatoid Arthritis (RA). This is the first published report of this association. It has obvious implications for NMOSD patients receiving anti-IL6 therapy.

Development of new white matter lesions suggestive of MS in a patient treated with anti-IL6 therapy might represent an important complication of therapy.

This case illustrates that tocilizumab might cause secondary auto-immunity in CNS. It is important to be aware of this potential complication as anti-IL6 therapy might become an option for the treatment NMOSD.