Introduction: Rituximab causes B cell depletion and is increasingly used off-label to treat autoimmune and inflammatory disorders of the CNS in children, adolescents and adults.

Methods: Multicentre retrospective review of the utility and safety of Rituximab treatment in children and adolescents with autoimmune and inflammatory CNS disorders.

Results: 144 children and adolescents (103 females, mean age 7.8 yrs, median 8, range 0.7-17) with NMDAR encephalitis (n=39), opsoclonus myoclonus ataxia syndrome (n=32), neuromyelitis optica (n=20), neuropsychiatric lupus (n=18), and other neuro-inflammatory disorders (n=35); were studied with a mean follow-up of 2.16 years. Infusion adverse events were recorded in 18/144 (12.5%) including Grade 4 (anaphylaxis) in three, and all were transient and uncomplicated. 11 patients (7.6%) had an adverse infectious events. A definite, probable or possible benefit was reported in 125 of 144 (87%) patients. 17.4% of patients had a modified Rankin scale (mRS) of 0-2 at Rituximab initiation, compared to 73.9% at outcome. For the four main indications, the change in mRS 0-2 was larger in patients given early Rituximab compared to those treated later.

Conclusion: Rituximab is being used as a second line agent in children with severe autoimmune and inflammatory CNS disease. While limited by the retrospective nature of this analysis, our data suggest a role for the off-label use of Rituximab in severe autoimmune CNS disease. This safety data will help inform risk versus benefit discussions with families.