Cerebrospinal fluid is abnormal in 85-90% of patients with multiple sclerosis (MS). The abnormalities include an elevated total IgG, an elevated IgG ratio, and an increased IgG synthesis rate. The soluble clonal immunoglobulin G, also referred to as oligoclonal bands in the CSF is an immunodiagnostic feature. These are not present in simultaneously drawn serum samples.
Discovery of oligoclonal bands have been associated with a more rapid conversion from clinically isolated syndrome to clinically definite MS.
Natalizumab, a peripherally acting very late antigen (VLA)-4 monoclonal antibody, blocks immune cell migration into the CNS and effectively reduces MS disease activity. Under its effect, the CSF IgG levels can decrease and oligoclonal bands can disappear.