Characterization of children with early onset pediatric multiple sclerosis

Background: Early onset pediatric multiple sclerosis (EOPMS) provides an early window of opportunity to understand the mechanisms leading to MS. Objective: To investigate clinical, laboratory and imaging differences between children with early onset pediatric MS (<11 years, EOPMS) and late onset pediatric MS (≥11 years, LOPMS). Methods: Mostly prospectively collected data of children with MS including clinical presentation, MRI at onset, time to second relapse, relapse rate, treatment history, and CSF markers were eligible. Results: In total 274 children were included, n = 53 children with EOPMS and n = 221 children with LOPMS. In children with EOPMS both sexes were equally affected, while in LOPMS the female sex was more prevalent (p < 0.001). Presence of additional oligoclonal bands (OCBs) in the cerebrospinal fluid (CSF) was comparable in both age groups (92.3 % vs 89.5 %). Children with EOPMS had more relapses in the first 2 years (p = 0.004). Children with LOPMS had significantly more spinal lesions (p = 0.001). Presence of a prior EBV infection tested in a subset of children with EOPMS (n = 34) was only detected in 27/34 (79 %). Conclusion: Our findings suggest that both groups share important similarities but also important differences such as an increased relapse rate and a higher amount of infratentorial lesions in EOPMS. Furthermore, our results allude to a prior EBV-infection possibly not being an indispensable requirement for the development of MS in children with EOPMS.