The most frequent pathological CSF finding was positive OCB (see above) followed by quantitative intrathecal IgG synthesis (51.5% in PPMS patients and 50.0% in RRMS; n.s.), elevated total CSF cell count (PPMS: 22.3%, RRMS: 43.0%; p < 0.01), quantitative intrathecal IgM synthesis (PPMS: 8.7%, RRMS: 14.8%; n.s.)and quantitative intrathecal IgA synthesis (PPMS: 7.8%, RRMS: 8.0%; n.s.). Here, CD40LG is linked to primary progressive multiple sclerosis.