Defining active progressive multiple sclerosis.

BACKGROUND

It is unknown whether disease activity according to consensus criteria (magnetic resonance imaging activity or clinical relapses) associate with cerebrospinal fluid (CSF) changes in progressive multiple sclerosis (MS).

OBJECTIVE

To compare CSF biomarkers in active and inactive progressive MS according to consensus criteria.

METHODS

Neurofilament light chain (NFL), myelin basic protein (MBP), IgG-index, chitinase-3-like-1 (CHI3L1), matrix metalloproteinase-9 (MMP-9), chemokine CXCL13, terminal complement complex, leukocyte counts and nitric oxide metabolites were measured in primary ( n = 26) and secondary progressive MS ( n = 26) and healthy controls ( n = 24).

RESULTS

Progressive MS patients had higher CSF cell counts, IgG-index, CHI3L1, MMP-9, CXCL13, NFL and MBP concentrations. Active patients were younger and had higher NFL, CXCL13 and MMP-9 concentrations than inactive patients. Patients with active disease according to consensus criteria or detectable CXCL13 or MMP-9 in CSF were defined as having combined active progressive MS. These patients had increased CSF cell counts, IgG-index and MBP, NFL and CHI3L1 concentrations. Combined inactive patients only had increased IgG-index and MBP concentrations.

CONCLUSION

Patients with combined active progressive MS show evidence of inflammation, demyelination and neuronal/axonal damage, whereas the remaining patients mainly show evidence of active demyelination. This challenges the idea that neurodegeneration independent of inflammation is crucial in disease progression.