Serum IgM to Lipids Predicts the Response to Tysabri® and IFN-β in MS

Background: IgM has been associated with oligodendrocyte and axonal damage indicating a main role in MS pathophysiology. Serum IgM reactive with PC (IgM-PC) is detected in multiple sclerosis (MS) patients. We aimed to analyze the role of serum IgM-PC as biomarkers of response to treatment.Materials: Paired serum samples from 95 MS patients were obtained before and after treatment with disease modifying therapies. Patients were classified as non-responders or responders to treatment, according to the number of relapses or the progression of the disease. Serum IgM-PC concentration was analyzed using an ELISA assay developed in our lab.Results: The 73.3% of patients with high basal IgM-PC levels responded to Tysabry® treatment. We detected a reduction of serum IgM-PC levels in the 90.90% of patients treated with Tysabri®, regardless of whether the treatment was effective. We did not detect significant differences in the levels of serum IgM-PC after the treatment with Avonex® or Copaxone®. The 63.6% of patients with high basal IgM-PC level responded to Rebif® or Betaferon®. Patients who did not respond to Rebif® or Betaferon® showed similar levels of serum IgM-PC before and after the treatment. On the contrary, we detected decreased IgM-PC serum levels in responders to this disease modifying therapies.Conclusions. Serum IgM-PC could be a biomarker of response to Tysabri® or IFN-β treatment. However, further studies in larger cohorts would be necessary to confirm these results.Funding Information: This work was supported by grants: MCP20V10; MCP19V09; BSCON068 from Banco Santander-Universidad San Pablo; MEMERG-1 from IMMA, Universidad San Pablo CEU; PI16/01259, PI15/00821 and PI18/00204 from Instituto de Salud Carlos III; and “Fundación LAIR”. M.C.S. was supported by a fellowship form the CEU-Banco Santander (XII Convocatoria de ayudas a la movilidad investigadora CEU-BANCO SANTANDER) Santander. C.S. was supported by a fellowship from Fundación Universitaria San Pablo-CEU–Instituto de Medicina Molecular Aplicada.Declaration of Interests: Authors have nothing to disclose.Ethics Approval Statement: Approved by the Bioethics Committe of Hospital Clínico San Carlos (Madrid Spain). All the patients gave verbal and written informed consent for sample collection.