CD40LG and multiple sclerosis: <h4>Objectives</h4>We aimed to develop a simple, cost-effective algorithm to predict the presence of oligoclonal IgM bands (OCMB) in patients with multiple sclerosis (MS), using surrogate markers such as the IgM Index (IgMi) and the Free Kappa Light Chains Index (FKLCi), with the aim of reducing the need for OCMB testing while maintaining high diagnostic accuracy.<h4>Methods</h4>A retrospective study was conducted using paired serum and cerebrospinal fluid samples from patients diagnosed with MS at disease onset at Hospital Universitari i Politècnic La Fe.