B-cell subsets up-regulate α4 integrin and accumulate in the cerebrospinal fluid in clinically isolated syndrome suggestive of multiple sclerosis onset

▶ Circulating B-cell subsets of patients with CIS up-regulated the α4 integrin. ▶ The α4 expression correlated with the disease activity, measured by brain MRI. ▶ CSF analysis reflected that all B-cell subsets cross the BBB after the CIS. ▶ CSF of CIS patients were enriched with switched and unswitched CD27+ memory B-cells.