Chronic graft-versus-host disease myelitis successfully treated with rituximab.

Chronic graft-versus-host disease (cGVHD) is a major serious complication after allogeneic stem-cell transplantation (allo-HSCT), and often mimics autoimmune diseases. Central nervous system (CNS) symptoms are rare manifestations of cGVHD, and are difficult to diagnose. CNS manifestations of cGVHD were discussed in the 2020 National Institutes of Health cGVHD Consensus Project as one of the "atypical cGVHD manifestations" with involvement of various organ systems other than classical cGVHD organs. We experienced a case of myelitis after allo-HSCT diagnosed as cGVHD of the CNS. The neurological symptoms progressed after corticosteroid pulse therapy, resulting in severe paralysis and paresthesia of the lower extremities. The clinical course and magnetic resonance imaging findings showed some similarities with multiple sclerosis. We decided to use rituximab after the patient became refractory to corticosteroids because rituximab has been reported to be effective in multiple sclerosis by suppressing B cells on both sides of the blood-brain barrier. Rituximab was effective for the neurologic symptoms in our case. In atypical cGVHD, treatments used in corresponding autoimmune diseases may be reasonable and effective.