Background

NMOSD is an autoimmune condition commonly involving the optic nerve and spinal cord. Pediatric onset NMOSD is rare, representing 3% of cases, with a mean age of onset of 10 years. Presenting features in these patients include optic neuritis, myelitis, brainstem, diencephalic, and cerebral syndromes. Acute treatments include plasma exchange (PLEX) and steroids. Early initiation of immunosuppression is critical to prevent relapses and disability. In adults with refractory NMOSD, autologous hematopoietic stem cell transplant (AHSCT) has been utilized as a salvage therapy. We report the first case to our knowledge of a child with AQP4 NMOSD receiving AHSCT.

Objectives

We report a child with an early and severe manifestation of an AQP-4 positive NMOSD who had a refractory course despite aggressive immunotherapy and underwent AHSCT.

Methods

Case report featuring clinical presentation, laboratory, neuroimaging, discussion of medical decision-making and specific treatment protocol used for AHSCT.

Results

A 2 year old girl presented with left hand weakness and abnormal gait and was found to have abnormalities in the dorsal medulla and longitudinally extensive myelitis. She was diagnosed with NMOSD based on positive CSF and serum AQP-4 antibody.

She has had highly active disease with 7 hospitalizations (5 of which she received PLEX) for exacerbations involving holocord edema, bilateral optic neuritis, parenchymal brain lesions, area postrema syndrome, and hypothalamus.

She was initially placed on rituximab but had rapid B cell repopulation. She was transitioned to mycophenolate mofetil (MMF), titrated up to 85 mg/kg/day, but still relapsed, even when Tocilizumab 8 mg/kg monthly was added on to MMF. While her attacks continued to be partially responsive to acute therapies, serial imaging revealed increasing myelomalacia and optic nerve atrophy.

She later underwent a myeloablative AHSCT with conditioning using rituximab, cyclophosphamide, and rabbit thymoglobulin without significant complication. Her home MMF, prednisone, and Tocilizumab were discontinued prior to transplant. A week after full engraftment of stem cell transplant, she started to have worsening visual symptoms and was found to have enhancing lesion of the optic chiasm with elevated anti-AQP4 titers at > 1:100,000. She then received PLEX and IV steroids with significant clinical improvement. She has since had no further NMOSD exacerbations and had a recent admission for febrile neutropenia.

Conclusions

AHSCT has been increasingly utilized in refractory cases of adult NMOSD, showing good efficacy, tolerability, and potential for enduring disease remission. We present this case to highlight its first use to our knowledge in pediatric NMOSD, unfortunately complicated by a relapse shortly after engraftment and subsequent hospitalization for febrile neutropenia. The long-term efficacy and safety of this treatment in children requires further investigation.

Background

NMOSD is an autoimmune condition commonly involving the optic nerve and spinal cord. Pediatric onset NMOSD is rare, representing 3% of cases, with a mean age of onset of 10 years. Presenting features in these patients include optic neuritis, myelitis, brainstem, diencephalic, and cerebral syndromes. Acute treatments include plasma exchange (PLEX) and steroids. Early initiation of immunosuppression is critical to prevent relapses and disability. In adults with refractory NMOSD, autologous hematopoietic stem cell transplant (AHSCT) has been utilized as a salvage therapy. We report the first case to our knowledge of a child with AQP4 NMOSD receiving AHSCT.

Objectives

We report a child with an early and severe manifestation of an AQP-4 positive NMOSD who had a refractory course despite aggressive immunotherapy and underwent AHSCT.

Methods

Case report featuring clinical presentation, laboratory, neuroimaging, discussion of medical decision-making and specific treatment protocol used for AHSCT.

Results

A 2 year old girl presented with left hand weakness and abnormal gait and was found to have abnormalities in the dorsal medulla and longitudinally extensive myelitis. She was diagnosed with NMOSD based on positive CSF and serum AQP-4 antibody.

She has had highly active disease with 7 hospitalizations (5 of which she received PLEX) for exacerbations involving holocord edema, bilateral optic neuritis, parenchymal brain lesions, area postrema syndrome, and hypothalamus.

She was initially placed on rituximab but had rapid B cell repopulation. She was transitioned to mycophenolate mofetil (MMF), titrated up to 85 mg/kg/day, but still relapsed, even when Tocilizumab 8 mg/kg monthly was added on to MMF. While her attacks continued to be partially responsive to acute therapies, serial imaging revealed increasing myelomalacia and optic nerve atrophy.

She later underwent a myeloablative AHSCT with conditioning using rituximab, cyclophosphamide, and rabbit thymoglobulin without significant complication. Her home MMF, prednisone, and Tocilizumab were discontinued prior to transplant. A week after full engraftment of stem cell transplant, she started to have worsening visual symptoms and was found to have enhancing lesion of the optic chiasm with elevated anti-AQP4 titers at > 1:100,000. She then received PLEX and IV steroids with significant clinical improvement. She has since had no further NMOSD exacerbations and had a recent admission for febrile neutropenia.

Conclusions

AHSCT has been increasingly utilized in refractory cases of adult NMOSD, showing good efficacy, tolerability, and potential for enduring disease remission. We present this case to highlight its first use to our knowledge in pediatric NMOSD, unfortunately complicated by a relapse shortly after engraftment and subsequent hospitalization for febrile neutropenia. The long-term efficacy and safety of this treatment in children requires further investigation.