CD40LG and multiple sclerosis: CSF OCB and both Ig indices were associated with conversion to multiple sclerosis at 5 years in univariate analysis (OCB: HR 4.0 [CI: 1.19–13.06], P < 0.05; IgG index: HR 3.5 [CI: 1.38–9.00], P < 0.01; IgM index: HR 2.8 [CI: 1.11–7.19], P < 0.05) (Fig. 2A).