Age has high influence on clinical course of chronic inflammatory diseases such as multiple sclerosis (MS). Lipid-specific oligoclonal IgM bands (LS-OCBM) in cerebrospinal fluid (CSF) of MS patients are biomarkers of high inflammatory disease. However, the relationship between both variables has not been fully studied.
To explore age-related changes in CSF of MS patients leading to senescence and to study the role of LS-OCBM in this process.
A prospective cross-sectional study of 263 MS patients followed at Ramon y Cajal University Hospital, Madrid. Seventy-two showed (M+) and 191 (M-) lacked CSF LS-OCBM. We explored CSF immune cells, soluble mediators, microRNAs and clinical data.
MS patients older than 45 years (O45) showed significant rises in CSF Programmed death ligand 1 (PD-L1; p=0.001) and T-cell immunoglobulin mucin-3 (TIM-3; p<0.0001), which induce lymphocyte tolerance, and in Chitinase 3-like-1 (p<0.0001) and Activin-A (p<0.0001), which lead to innate cell activation. This associated with low values of pro-inflammatory B cells and of Th17 lymphocytes. In addition, M- O45 patients experienced significant increases in miR-125b-5p (p=0.01) and miR-145-5p (p=0.02), two miRNA associated with immune senescence, an increase of let-7b-5p (p=0.01) that counteract innate-cell activation, a dramatic decrease of CSF lymphocytes (p<0.0001) and of NK cells (p=0.002) and increased serum anti-cytomegalovirus antibodies (p=0.009). However, M+ O45 patients exhibited a reduction of miR-204-5p (p=0.01), that induce innate-cell activation and increased CSF levels of superoxide dismutase (p=0.04) and isoprostane (p=0.03), markers of oxidative stress. These changes resulted in increased Multiple Sclerosis Severity Score (MSSS) on M+ O45 patients.
M- O45 MS patients showed inhibition of the intrathecal adaptive immune response and early immunosenescence. Conversely, M+ O45 MS patients displayed intrathecal innate cell activation and accelerated disability worsening. These data could be relevant for treating aged MS patients.