Abstract
Treatment options for progressive MS (PMS) are limited in numbers and efficacy, which is most pronounced in patients with inflammatory disease activity. Immunoglobulin M (IgM) oligoclonal bands (OCBs) may identify a subset of PMS with more active inflammatory disease. The effects of natalizumab and methylprednisolone on intrathecal inflammation and the association of IgM OCBs with other biomarkers in PMS is uncertain. In the current study, we investigated the cerebrospinal fluid (CSF) proteome of untreated patients with PMS, effects of natalizumab and methylprednisolone, and associations of IgM OCBs with disease activity and CSF biomarkers. We found a reduction of BCMA, SLAMF7, granzyme A, IgG, and desmoglein-2 with both therapies, as well as natalizumab-specific reductions of VCAM-1, CD48, MDC, MMP-9, sE-selectin, and CHIT1, and methylprednisolone-specific reductions of DR3, IgD, RTN4, and increases of sCD206, LYVE1, sCD163 and MMP-3. IgM OCBs were associated with reduced levels of PIGR, higher levels of NFL and VEGF, and more contrast-enhancing lesions. The study suggests T and B cell activity biomarkers as treatment-responsive CSF biomarkers in PMS. Additionally, we found natalizumab to reduce adhesion molecules and methylprednisolone to increase myeloid biomarkers. Lastly, we confirm that IgM OCBs are associated with a more inflammatory MRI and CSF profile.