Intrathecal IgG synthesis in relapsing-remitting multiple sclerosis (MS) is decreased by natural human alpha interferon

Intrathecal IgG synthesis (IT IgG Syn) is an established biomarker used for the diagnosis of multiple sclerosis (MS). Earlier studies used this biomarker to assess the impact of 2 different synthetic forms of interferon alpha (IFN-α) in chronic progressive MS. Unexpectedly, IT IgG synthesis was increased by this treatment. For the first time, we have assessed this parameter in relapsing-remitting patients to measure the impact of natural IFN-α treatment in a doseranging study in six dosage groups (5, 10, 15, 20, 25, & 30 MIU). We have found that IFN-α normalized IT IgG Synthesis at 12 weeks treatment for all dosage groups. Two weeks after stopping IFN-α results rose slightly. At 52 weeks, 28 weeks after stopping IFN-a results revealed cessation of IT IgG Synthesis in half of the patients (15, 20, 25 MIU weekly). These results reflect different outcomes for relapsing-remitting patients vs. chronic progressive patients. They may, however, reflect differences in the biological properties of the interferon products used. An optimal range of dosage with natural human IFN-α dosage for MS is suggested by the results.