Laboratory Lead: to be appointed
Clinical Lead: Dr Michael Lunn
The Unit continues to focus on body fluid biomarkers of key pathological processes that are believed to be important neurological diseases of the central and peripheral nervous system.
CSF neurofilament phosphoisoforms, a measure of axonal damage and/or loss, correlate and predict the development of disability in patients with established MS. Studies on novel markers of neuronal and axonal regeneration, such as soluble Nogo receptors, are ongoing. Neurofilament proteins may also have a prognostic role in Guillain-Barré syndrome; this has important practical implications in terms of allocation of resources, which could be required in the more severe cases of this syndrome, as well as directing more carefully the expensive drugs used in the treatment of this condition (i.e. plasmapheresis and/or intravenous immunoglobulin). In conjunction with the Department of Neurodegenerative Disease and also the Sobell Department of Motor Neuroscience and Movement Disorders we are exploring alterations in CSF biomarkers in a number of dementia and movement disorder syndromes.
We have recently developed a novel assay to detect neutralising anti-interferon beta antibodies that develop in a significant proportion of subjects with MS who are treated with interferon beta. This assay uses a stably transfected cell line with the firefly luciferase gene under the control of an interferon response element as a rapid readout of interferon beta activity. The assay does not require a final protein or mRNA quantification step. We are now using this assay in clinical practice and in research studies to evaluate the effect of neutralising antibodies on interferon beta therapy and to probe the effects of interferon on the reactivation of latent herpes viruses.
Dr Michael Lunn is exploring the neuroprotective effect of sodium channel blockade in experimental allergic neuritis. If the agent is shown to be safe and effective in this model system then we will commence human trials to explore the neuroprotective effect in the peripheral neuroinflammatory condition, Guillain-Barré syndrome. With Dr Elspeth Hutton and Professor Martin Koltzenburg we are examining changes in histopathological and neuroimmune skin biomarkers to correlate changes with the occurrence of pain in inflammatory and non-inflammatory small fibre neuropathy syndromes.
Dr Geoff Keir has recently shown that a higher level of local sensitivity as well as increased dynamic range is available for the detection of brain-specific proteins, using the novel approach of enhanced release of light under a strong electric field. This also has the more important practical advantage of enabling the performance of an immunoassay in about 15 minutes, a possible practical bedside use for this technology in the surgical intensive care unit and/or theatre, to monitor the course of surgery. In collaboration with Mr Stuart McCombie (Department of Neuroimmunology, NHNN), we have shown that the a digital camera with low light sensitivity can be used instead of the more cumbersome dark-room technique of laying X-ray films on top of proteins separated by Western blotting. This technique should allow more quantitative methods of analysis to be applied, not least for the kinetics of the chemiluminescent reactions, which can thereby also be optimised in due course. The work of Mr Miles Chapman (Department of Neuroimmunology, NHNN), has allowed quantitative estimation of the amounts of high-affinity antibody in CSF from patients with brain infection, as opposed to the low-affinity non-specific immune responses seen in multiple sclerosis. He has used a model system based on readily available commercial reagents (i.e. human serum albumin and its antiserum).
Autoimmune dysfunction of the basal ganglia has been implicated in Sydenham’s chorea, paediatric autoimmune neuropsychiatric disorders associated with streptococcal infection (PANDAS), Tourette’s syndrome and in a wide spectrum of patients with complex movement disorders. These patients have circulating anti-basal ganglia antibodies (ABGAs). It has been proposed that these antibodies are induced in response to streptococcal infection and cross-react with antigenic determinants in the basal ganglia by the process of molecular mimicry. We have shown that the ABGAs from these patients recognise antigens of molecular weights 40, 45, 60 and 98kDa. These antigens have been purified (ammonium sulphate purification, 2-dimensional electrophoresis, ion exchange chromatography and hydrophobic interaction chromatography) and identified as aldolase C, non-neuronal and neuronal specific enolase, and pyruvate kinase M1, respectively. All of these proteins are the neuronal isoforms of glycolytic enzymes and are found in both neuronal cytoplasm and membrane, and some (enolase) are also expressed on the surface of streptococci. Interestingly, paediatric subjects with ABGA appear to have persistent nasopharyngeal colonisation with streptococci. We are currently investigating whether ABGA-associated strains of streptococci from these patients differ from other “wild-type” strains.