Search

Background: B lymphocytes are thought to play a relevant role in multiple sclerosis (MS) pathology. The in vivo analysis of intrathecally produced B cell-related cytokines may help to clarify the mechanisms of B cell recruitment and immunoglobulin production within the central nervous system (CNS) in MS.Methods: Paired cerebrospinal fluid (CSF) and serum specimens from 40 clinically isolated syndrome suggestive of MS or early-onset relapsing-remitting MS patients (CIS/eRRMS) and 17 healthy controls (HC) were analyzed for the intrathecal synthesis of IgG (quantitative formulae and IgG oligoclonal bands, IgGOB), CXCL13, BAFF, and IL-21. 3D-FLAIR, 3D-DIR, and 3D-T1 MRI sequences were applied to evaluate white matter (WM) and gray matter (GM) lesions and global cortical thickness (gCTh).Results: Compared to HC, CIS/eRRMS having IgGOB (IgGOB+, 26 patients) had higher intrathecal IgG indexes (p < 0.01), lower values of BAFF Index (11.9 ± 6.1 vs 17.5 ± 5.2, p < 0.01), and higher CSF CXCL13 levels (27.7 ± 33.5 vs 0.9 ± 1.5, p < 0.005). In these patients, BAFF Index but not CSF CXCL13 levels inversely correlated with the intrathecal IgG synthesis (r > 0.5 and p < 0.05 for all correlations). CSF leukocyte counts were significantly higher in IgGOB+ compared to IgGOB- (p < 0.05) and HC (p < 0.01), and correlated to CSF CXCL13 concentrations (r 0.77, p < 0.001). The gCTh was significantly lower in patients with higher CSF CXCL13 levels (2.41 ± 0.1 vs 2.49 ± 0.1 mm, p < 0.05), while no difference in MRI parameters of WM and GM pathology was observed between IgGOB+ and IgGOB-.Conclusions: The intrathecal IgG synthesis inversely correlated with BAFF Index and showed no correlation with CSF CXCL13. These findings seem to indicate that intrathecally synthesized IgG are produced by long-term PCs that have entered the CNS from the peripheral blood, rather than produced by PCs developed in the meningeal follicle-like structures (FLS). In this study, CXCL13 identifies a subgroup of MS patients characterized by higher leukocyte counts in the CSF and early evidence of cortical thinning, further suggesting a role for this chemokine as a possible marker of disease severity. [ABSTRACT FROM AUTHOR]

B-cells are thought to play a relevant role in multiple sclerosis (MS) pathology. BAFF (B cell activating factor of the TNF family) is a B-cell survival factor constitutively produced inside the CNS by astrocytes. We studied the intrathecal synthesis of BAFF in MS at clinical onset. Paired serum and cerebrospinal fluid (CSF) specimens from 40 clinically isolated syndromes (CIS) suggestive of MS or early relapse-onset MS (eRRMS) and from 18 healthy controls (HC) were analysed. Patients were classified based on the detection of oligoclonal IgG bands in the CSF (IgGOB + and IgGOB −). BAFF was detected by highly sensitive ELISA and its ratio (CSF-BAFF/serum-BAFF, Q BAFF ) and Index (Q BAFF /Q Alb , BAFF-Index) were calculated. IgGOB + presented lower CSF concentrations of BAFF compared to both HC and IgGOB − (p < 0.05). BAFF Index was significantly lower in IgGOB + compared to both HC and IgGOB − (p < 0.01). A significant inverse correlation between Q IgG and Q BAFF (r: − 0.4, p < 0.05) and between BAFF index and IgGIF (r: − 0.4, p < 0.05) or IgG Index (r: − 0.4, p = 0.05) was found in IgGOB +. The decreased CSF levels of BAFF in IgGOB + at clinical onset suggest the absorption of this factor by intrathecally recruited B cells since the early disease phases. [ABSTRACT FROM AUTHOR]