Immunoadsorption plasmapheresis treatment for the recurrent exacerbation of neuromyelitis optica spectrum disorder with a fluctuating anti-aquaporin-4 antibody level.

The pathogenesis in the exacerbation of neuromyelitis optica spectrum disorder (NMOSD) involves mainly the serum anti-aquaporin-4 (AQP4) immunoglobulin G antibody (anti-AQP4 antibody). If high-dose corticosteroid treatment is not achieved during remission, rescue plasmapheresis is recommended. However, there are few reports on the therapeutic efficacy of repetitive immunoadsorption plasmapheresis (IAPP) for the recurrent exacerbation of NMOSD with a fluctuating anti-AQP4 antibody level. A 36-year-old man presented with a reduction of visual acuity (VA) on the right eye (OD) to 20/250. At this reduction of VA OD, magnetic resonance imaging (MRI) showed right optic nerve swelling without cerebral, brainstem, or spinal cord lesions. The anti-AQP4 antibody was detected in the serum. We diagnosed the patient with NMOSD and treated him with high-dose corticosteroid therapy. To prevent exacerbation with this treatment, the sixth session of the first IAPP course was adopted and VA OD improved to 20/100. Seven months later, VA OD deteriorated to 20/125 and ocular pain occurred. At that time, the anti-AQP4 antibody was not detected, although MRI revealed the recurrence of right optic neuritis. A second IAPP course with seven sessions was conducted with a concomitant administration of 1000 mg methylprednisolone every 10 days for 30 days. Ocular pain improved, although VA OD had continued to decline during these treatments and was eventually preserved at 20/400. In conclusion, IAPP is effective for the treatment of exacerbated NMOSD with a seropositive anti-AQP4 antibody. However, further study is necessary to develop treatments for relapsing NMOSD with a seronegative anti-AQP4 antibody.