Multiple sclerosis : BAFF and CXCL13 in cerebrospinal fluid

Background: There is increasing evidence of B-cell involvement in the pathogenesis of multiple sclerosis (MS). B-cell activating factor (BAFF) has an essential role in B-cell homeostasis. The chemokine CXCL13 has an important role in the formation and maintenance of B-cell follicles. Objective: To measure BAFF and CXCL13 levels in the cerebrospinal fluid (CSF) of patients with MS compared to patients with other neurological diseases. Methods: Cytokine/chemokine levels were measured by an enzyme-linked immunosorbent assay (ELISA). Results: In MS patients, BAFF levels were highest in patients with secondary progressive disease, and were higher during relapse in patients with relapsing-remitting and secondary progressive disease. CXCL13 levels were also higher during relapse. There was a positive correlation between CXCL13 and the IgG index, and an inverse correlation between BAFF and the IgG index. The implications of this finding are discussed. Conclusion: During relapse, we found various positive correlations between BAFF, CXCL13 and the cytokines IL-6 and IL-10. These findings show that molecules that are essential for B-cell recruitment, survival, maturation and function may be working in concert to affect B-cell homeostasis in MS and contribute to the pathophysiology of the disease.