Cerebrospinal fluid oligoclonal IgM bands predict early conversion to clinically definite multiple sclerosis in patients with clinically isolated syndrome.

We reviewed the records of 391 patients who had presented with a Clinically Isolated Syndrome and selected 205 who had performed a baseline spinal tap and MRI scan. We studied cerebrospinal fluid (CSF) and serum IgM oligoclonal bands (IgMOB) using agarose gel isoelectric focusing and analyzed the impact of baseline clinical, MRI and CSF variables on the risk of conversion to clinically definite multiple sclerosis, i.e. on the risk of a clinical relapse. At survival analysis, a lower age at onset, an onset with optic neuritis and the presence of CSF-restricted IgMOB increased the risk of a relapse. Only the presence of CSF-restricted IgMOB predicted a relapse within one year.