B cell-related immunophenotyping and protein profile of cerebrospinal fluid in multiple sclerosis patients at diagnosis.

Introduction: Chronic inflammation, compartmentalized within intracerebral sites, as meninges, perivascular cuffs and cerebrospinal fluid (CSF), represents one of the main pathological features of Multiple Sclerosis (MS), highly contributing to the progression of the disease. Aim of the Study: To evaluate early cell and molecular pattern of CSF inflammation in early MS patients and to cross-correlate the inflammatory signatures of CSF cells and protein biomarkers with clinical-radiological parameters at time of diagnosis. Methods: Comprehensive immunophenotyping (BeckmanCoulter-Navios -Cytometer) of CSF leukocytes was combined with analysis of the presence and levels of79 inflammatory proteins (Bio-Plex Immunoassay System)in CSF collected at time of diagnosis from 22 naïve MS patients. Each patient was subjected to a detailed clinical and radiological assessment (3 Tesla Magnetic Resonance Imaging). Results: By examining the correlations between clinical and MRI imaging parameter of MS patients with proportion and type of CSF immune cells, significant (p<0.01) positive correlation (R=0.58) was found between number of Gad-enhancing lesions and percentage of CD3+CD4+ helper T cells. On the contrary, spinal cord and cortical lesion load was found significantly associated with percentage of CD19+ B cells (R=0.79 and R=0.67 respectively) and of classic monocytes (CD16- CD14+) (R=0.87 and R=0.63 respectively). Finally, global cortical thickness was found associated with percentage of intermediate monocytes (CD16+ CD14+) (R=0.63). The majority of CSF B cells at diagnosis were identified as IgG+CD27- switched B cells (63%), correlating with high protein levels of CXCL13, CXCL12, sTNFR1, APRIL, IL-6, IL-8, IL-10, IL-16, as well as exhausted CD21lowCD38lowB cells (31%), correlating with high protein levels of TNF, IL8, IL10, IL16, IL35, GM-CSF, Osteocalcin, sCD163, IgM, CX3CL1, CXCL1 and CCL25. Conclusion: A detailed cell and molecular profiling of CSF from MS patients at time of diagnosis may discriminate a subgroup of patients with increased B cell contribution at early disease stages and with particular involvement of spinal cord and/or grey matter demyelination.