Rathbone E, et al. - Study authors assessed if the ratio of cerebrospinal fluid (CSF) immunoglobulin kappa to lambda light chains at the time of multiple sclerosis (MS) diagnosis predicts disease progression, and if this was inherent to CSF plasmablasts. They reported that CSF immunoglobulin κ:λ ratios, established at the time of diagnostic lumbar puncture, forecast MS disease progression and may, therefore, be helpful predictive markers for early therapeutic stratification.