Clinical usefulness of prognostic biomarkers in optic neuritis

Different biological and radiological biomarkers predict clinical conversion to multiple sclerosis (MS) after a clinically isolated syndrome (CIS). The aim was to explore their role in predicting the outcome of patients with optic neuritis (ON), a CIS considered to have a benign prognosis.

Sixty-eight consecutive ON patients were followed prospectively. Magnetic resonance imaging (MRI) and cerebrospinal fluid studies including oligoclonal immunoglobulin G (IgG) bands (OCGBs), lipid-specific oligoclonal IgM bands (LS-OCMBs) and neurofilament light chain quantification were performed at disease onset. Conversion to clinically definite MS (CDMS) was monitored.

The mean time of follow-up of our series was 46.4 months. Twenty-five patients (36.7%) developed CDMS during follow-up. Neurofilament light chain levels did not predict clinical conversion. By contrast, an abnormal MRI increased the risk of CDMS [hazard ratio (HR) 12.5, P = 0.013]. The clearest association was found in patients with more than three T2 lesions. OCGBs also predicted the onset of CDMS (HR 21.3, P = 0.003) and LS-OCMBs were associated with a shorter time to CDMS (HR = 116.6, P < 0.001).

Magnetic resonance imaging and OCGBs predicted conversion to CDMS after an ON episode. In addition, LS-OCMBs identified the ON patients more likely to develop MS early. These results, applicable to the everyday clinical setting, may be of interest for therapeutic decisions.