Multiple sclerosis (MS) is an autoimmune neurodegenerative disease characterized by demyelination and neurodegeneration of the central nervous system (CNS) . Current diagnostic criteria and management depend on MRI, clinical status, and oligoclonal immunoglobulin g bands . These markers often fail to predict relapse, progression and therapy response .There is an increased need to identify biomarkers for clinical endpoints .

One of the hallmark features of MS is axonal damage which associated with brain and cervical atrophy.Nf levels indicate the extent of axonal damage. Neurofilaments are composed of four subunits: neurofilament light polypeptides (NfL) is the most abundant and soluble and it is highly sensitive to neurodegenerative processes .

Chitinase 3-like 1 (CHI3L1) is expressed in astrocytes in the brain tissue of MS patients . CHI3L1 plays a role as prognostic biomarker in patients with MS. CHI3L1 cerebrospinal fluid levels were associated correlated with disease activity and neurological disability.

Dendritic cells (DCs) are highly specialized antigen-presenting cells with a key role in activating and preventing CNS immune-mediated damage in MS . Dendritic cells express Human Leukocyte Antigen-antigen D Related (HLA-DR) . Plasmacytoid dendritic cells characterized by the expression of blood dendritic cells antigen-2 (BDCA-2) .Plasmacytoid dendritic cells are present in the cerebrospinal fluid (CSF), leptomeninges and demyelinating lesions of patients with MS . Plasmacytoid dendritic cells also exhibit up-regulation of chemokine (CCR7C) expression. It was demonstrated increased amounts of chemokine CCR7 in the CSF from MS patients during relapses .CCR7 controls migration and functional activity of regulatory T cells and plays an important role in the establishment of tolerance .

Tolerogenic DCs (TolDCs) present an intermediate phenotype between immature dendritic cells (iDCs) and mature dendritic cells (mDCs) regarding costimulatory molecules, a pronounced shift toward anti-inflammatory . TolDCs exhibit tolerogenic molecules such as HLA-G and CD274 [programmed death-ligand 1 (PD-L1)] either in peripheral blood or in CSF. These characteristics lead to T cell clonal anergy and T cell unresponsiveness due to Ag presentation in the presence of low co-stimulation .We aim to investigate the role of NfL,(CHI3L1) and markers of plasmacytoid dendritic cells in MS.

Inclusion Criteria: 1-MS patients diagnosis 2017 McDonald criteria. 2-Patients age 20-60 years 3-All males and female patients. 3-Willingness and ability to comply with the protocol. 4-Written informed consent given by the patient before the beginning of any study-related procedure, 5-Non-MS control matched age and sex persons

Exclusion Criteria:1-patients with Intracranial space-occupying lesion. 2-Abnormal intracranial pressure due to increased CSF pressure or Arnold-Chiari malformation.

3-Anticoagulant medication, coagulopathies and uncorrected bleeding diathesis. 4-Congenital spine abnormalities. 5-Local skin infection at the puncture site. 6-Not fulfill Macdonald criteria.

21 MS patients and 21 non-MS control perons.