# Neurological graft-versus-host disease with MOG antibody positivity after allogeneic stem cell transplantation: a case report

## TL;DR

A patient with neurological complications after a stem cell transplant showed low-titer MOG antibodies, suggesting a possible link between MOG antibody positivity and CNS-GVHD.

## Contribution

This case report highlights the potential role of live-cell-based MOG antibody testing in diagnosing atypical neuroinflammatory syndromes after HSCT.

## Key findings

- Low-titer MOG antibody positivity was detected only by live-cell immunofluorescence in a patient with CNS-GVHD.
- Neurological symptoms improved with IVIG and methylprednisolone treatment.
- Conventional MOG antibody assays were negative, emphasizing the need for alternative testing methods.

## Abstract

Central nervous system (CNS) involvement is recognized as a distinct manifestation of chronic GVHD (cGVHD). Myelin oligodendrocyte glycoprotein antibody–associated disease (MOGAD) is an autoimmune disorder targeting the CNS. Therefore, the occasional detection of MOG antibodies in patients with CNS-cGVHD may represent a manifestation within the spectrum of CNS-GVHD.

A 22-year-old female with severe aplastic anemia (AA) underwent maternal haploidentical hematopoietic stem cell transplantation (HSCT) in May 2021. During conditioning, she developed acute neurotoxicity. Subsequent complications included acute and chronic GVHD as well as posterior reversible encephalopathy syndrome (PRES). Three months after transplantation, she developed sensory deficits and ataxia, and cervical magnetic resonance imaging revealed inflammatory lesions consistent with cervical myelitis. Comprehensive neuroimmunological evaluation excluded alternative infectious, metabolic, or neoplastic etiologies. Anti–myelin oligodendrocyte glycoprotein (MOG) antibodies were negative by cell-based assay (CBA) and tissue-based assay (TBA), but demonstrated weak, low-titer positivity on live-cell immunofluorescence. Neurological function recovered following treatment with intravenous immunoglobulin (IVIG) and methylprednisolone.

This case illustrates low-titer post-HSCT MOG seropositivity detected only by a live cell–based assay in a patient who fulfilled diagnostic criteria for CNS-GVHD. Live cell–based MOG testing may be considered in selected HSCT recipients with unexplained or atypical neuroinflammatory syndromes despite negative conventional assays, with results interpreted cautiously as hypothesis-generating for individualized immunosuppressive management.