[A case of neuromyelitis optica spectrum disorders associated with primary biliary cholangitis: a twelve year follow-up study].

We report the case of a 51-year-old woman who developed neuromyelitis optica spectrum disorders (NMOSD) associated with primary biliary cholangitis (PBC). When she was 38 years old, she subacutely developed headache and urinary retention. A diffusion weighted image (DWI) on brain MRI showed high signal intensity in the left temporal white matter, and T weighted image (TWI) on spine MRI showed high signal intensities in the spinal cord. After the initial event, follow-ups at 2, 6 and 9 months revealed that she developed neurological symptoms, and TWI on spine MRI showed high signal intensities in the cervical and thoracic regions of the spinal cord. On each episode, she was treated a course of intravenous methylprednisolone which resulted in improvement of her symptoms. At the age of 39 years, the serum levels of biliary enzymes began to elevate, and the serum levels were markedly elevated after the age of 40 years. When she was 40 years old, she developed optic neuritis of the right eye. At the age of 41 years, spine MRI again showed the cervical and thoracic spinal cord lesions. At the age of 51 years, she subacutely developed dizziness and urinary retention. DWI on brain MRI showed high signal intensities in the pons and medulla oblongata, and TWI on spine MRI showed longitudinally extensive high signal intensities in the spinal cord, specifically between the C3 and C5 vertebral levels. The serological tests for autoantibodies revealed positive anti-aquaporine 4 antibody (AQP4-Ab), positive anti-mitochondrial antibody subtype M2 (AM2-Ab) and positive anti-nuclear antibody, and the interleukin-6 (IL-6) level was elevated in the cerebrospinal fluid. Simultaneous occurrence of AQP4-Ab-positive NMOSD and AM2-Ab-positive PBC is extremely rare, and has never been reported in Japan. The present case is the first case with simultaneous occurrence of AQP4-Ab-positive NMOSD and AM2-Ab-positive PBC in Japan. We suspect that IL-6, plasmablast and cytotoxic T lymphocyte were involved with the occurrence of NMOSD with PBC in the present case.