Fibrinogen is not elevated in the cerebrospinal fluid of patients with multiple sclerosis

We analyzed CSF and plasma fibrinogen levels together with routine parameters in patients with multiple sclerosis (MS), acute inflammatory diseases of the CNS (bacterial and viral meningoencephalitis, BM and VM) and PNS (Guillain-Barré syndrome; GBS), as well as in non-inflammatory neurological controls (OND) in a total of 103 patients. Additionally, MS patients underwent cerebral MRI scans at time of lumbar puncture.CSF and plasma fibrinogen levels were significantly lower in patients with MS and OND patients as compared to patients with BM, VM and GBS. There was a close correlation between fibrinogen levels and albumin quotient (rho = 0.769, p < 0.001) which strongly suggests passive transfer of fibrinogen through the blood-CSF-barrier during acute inflammation. Hence, in MS, the prototype of chronic neuroinflammation, CSF fibrinogen levels were not elevated and could not be correlated to clinical and neuroradiological outcome parameters.Although previous work has shown clear evidence of the involvement of fibrinogen in MS pathogenesis, this is not accompanied by increased fibrinogen in the CSF compartment.Fibrinogen is a soluble 340 kDa dimeric glycoprotein that is synthesized in the liver, secreted into the plasma and able to signal via a number of receptors expressed on cells of the hematopoietic, immune and nervous systems [1,2]. Apart from its pivotal role in thrombogenesis, inflammation, immune responses and atherogenesis, it is also a prominent acute-phase reactant. Transiently elevated plasma fibrinogen levels have been described in acute infectious diseases, in acute stroke and myocardial infarction; chronically raised plasma fibrinogen levels have been associated with an increased risk for cardiovascular diseases [3]. Whilst the significance of plasma fibrinogen is well established, the determination of fibrinogen in cerebrospinal fluid (CSF) has so far been restricted to descriptions of elevated fibrinogen degradation products in the CSF of patients wit