What are the characteristic cerebrospinal fluid (CSF) findings in multiple sclerosis (MS)?

From the Guidelines

The characteristic cerebrospinal fluid (CSF) findings in multiple sclerosis (MS) include the presence of oligoclonal IgG bands and/or an elevated IgG index, with lymphocytic pleocytosis typically less than 50/mm3, as defined by the international panel on the diagnosis of multiple sclerosis 1. The presence of oligoclonal bands in the CSF is a key finding, indicating intrathecal antibody production, and is detected through CSF electrophoresis.

• The oligoclonal bands are considered positive when present in the CSF but absent in the serum.
• An elevated IgG index or IgG synthesis rate also reflects increased immunoglobulin production within the CNS. Some key points to consider when interpreting CSF findings in MS include:
• The quality of CSF analysis can vary among laboratories, and it is essential to ensure that the analysis is done using state-of-the-art technology to obtain reliable results 1.
• The McDonald criteria, which include clinical presentation, MRI findings, and CSF analysis, are used to diagnose MS, with CSF findings providing supportive evidence of the immune and inflammatory nature of the disease 1.
• While CSF analysis cannot provide information about dissemination of lesions or events in time or space, it can help support the diagnosis of MS when imaging criteria are unclear or when the clinical presentation is atypical 1.

From the Research

Characteristic CSF Findings in Multiple Sclerosis

The characteristic cerebrospinal fluid (CSF) findings in multiple sclerosis (MS) include:

• Oligoclonal IgG bands (OCBs) in the CSF, which are detected in approximately 95% of MS patients 2
• Elevated IgG index, which is found in about 70% of MS patients 2
• Presence of oligoclonal IgM bands (IgMOB) in some MS patients, which may be associated with a more severe disease course 3
• Increased CSF cell count, total protein, and IgG levels in some MS patients 3

CSF Findings and Disease Course

The presence of OCBs and elevated CSF parameters may be associated with certain disease courses, such as:

• Relapsing-onset MS (ROMS) versus primary-progressive MS (PPMS) 4
• Benign disease course, as indicated by negative OCB results 5
• Disease progression, which may be independent of OCB status 4

Diagnostic Utility of CSF Findings

The CSF findings, particularly OCBs, have a high sensitivity and specificity for MS diagnosis:

• Sensitivity of 82.6% and specificity of 79.9% for positive IgG-OCB patterns 5
• Good positive predictive value and specificity for MS diagnosis and clinical relapse within one year from onset, using CSF CXCL13 levels ≥15.4 pg/ml 3