CSF cellular and immunoglobulin G (IgG) profiles in 40 earlier-onset (<11 years) and 67 later-onset (>11 and <18 years) pediatric MS patients were compared in a multicenter US study. Earlier-onset patients had a mean age of 7.2 +/- 2.7 years (60% female), and later-age patients 15.1 +/- 1.7 years (63% female). CSF white blood cell counts were higher in earlier-onset patients (median^ 9 mm3 vs 6mm3 (p=0.15) but had a lower proportion of lymphocytes (70% vs 93%, p=0.0085) and a higher proportion of neutrophils (p=0.033). An elevated IgG index occurred in fewer earlier-onset disease patients than in the later-onset group (35% vs 68%, p=0.031). An activation of the innate rather than the adaptive immune system in the earlier stages of MS is suggested or an immature immune response. 
COMMENT. The CSF profile in pediatric MS is dependent on age of onset, and the age-related variations are important in diagnosis. Pohl D et al  reported the CSF characteristics of 136 childhood-onset (<16 years) cases of MS. CSF pleocytosis occurred in 66%, and oligoclonal IgG in 92%.