CSF oligoclonal bands and normal appearing white matter periventricular damage in patients with clinically isolated syndrome suggestive of MS

Background: A periventricular gradient of normal appearing white matter (NAWM) damage has been described in multiple sclerosis (MS), including subjects with clinically isolated syndrome (CIS). The pathological mechanisms underlying this gradient is not currently understood. Methods: 34 CIS subjects were enrolled and underwent cerebrospinal fluid oligo-clonal bands (CSF-OCB) evaluation. Moreover, all CIS subjects and 24 healthy controls underwent a brain MRI scan. Diffusion weighted imaging was used to compute mean diffusivity (MD) values in periventricular and deep NAWM for all groups. Results: CSF-OCB were present in 24 CIS subjects (CSF-OCB+) out of 34 tested. Periventricular NAWM MD values were significantly higher in CIS subjects with than in those without CSF-OCB (0.78 ± 0.06 mm 3 /10 −3 vs. 0.72 ± 0.06 mm 3 /10 −3 ; p = 0.01), while there was no difference between groups in deep NAWM MD values. The periventricular gradient of damage, expressed in z score based on healthy controls data, was more marked in CSF-OCB+ than in CSF-OCB− (0.65 ± 0.05 vs. 0.17 ± 0.04 p < 0.001). There was no difference in periventricular lesion load between the two groups. Conclusions: In CIS, the presence of CSF-OCB is associated with the severity of periventricular NAWM damage gradient. Intrathecal inflammation could play a role in NAWM damage distribution.