NEWER TESTS IN NEUROLOGY DR RAJESH V BENDRE HOD, IMMUNOCHEMISTRY METROPOLIS, MUMBAI

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1 NEWER TESTS IN NEUROLOGY DR RAJESH V BENDRE HOD, IMMUNOCHEMISTRY METROPOLIS, MUMBAI

2 The Central Nervous System was considered an Immunological Privileged Site Blood brain barrier (BBB) Proapoptotic molecules at BBB No MHC molecules on nerve cells No classical dendritic cells in the CNS However, Existence of lymph drainage in the CNS Passage of T and B cells through BBB (hypothalamus) Microglia can process and present antigens

3 Recent Advances in Neuroimmunology Interactions between the immune and the nervous system - Neural influences on the immune system Neurotransmitters: acetylcholine, norepinephrine, serotonin, etc. Neuropeptides: Substance P, endorphin Neurotrophic growth factors: Nerve growth factor, etc -Hormonal influences on the immune system - Epinephrine, glucocorticoids -Modulation of nerve cell function by immune and inflammatory mediators Cytokines Reactive oxygen and nitrogen species Similarities between nerve cells and immune cells Synapses K+ channels in immune cells (electroimmunology)

4 Classical Fields of Neuroimmunology Research Immune response to diseases of the nervous system Demyelinting/Autoimmune MS, NMO Degenerative- related to GAD & NMDA receptors Neoplastic- antineuronal antibodies Infections- CSF pathogen specific IgG antibodies

5 Multiple Sclerosis An Immunogenetic Disease Genetic Predisposition Twins studies HLA-DR2 (DRß1*1501) (antigen presentation) Environmental Factors Demographics/Epidemics Microbial Agents EBV Vitamin D IL-2Ra (regulatory T-cells) IL-7Ra (memory T-cells) Immune Dysregulation MS

6 MS CSF OCB Pattern Bands Observed Associated Diseases 1 Polyclonal pattern (no discrete bands) in both serum & CSF Rare Multiple sclerosis Myelitis CNS vasculitis Paraneoplastic syndromes Systemic lupus erythematosis 2 Same number of OCB in serum & CSF Myelitis CNS vasculitits Paraneoplastic syndromes Lupus CNS infections Neoplastic meningitis Behcet Disease Rasmussen Disease Hashimoto encephalitis Lymphoproliferative disorders Hepatitis C OCB in both serum & CSF CSF has at least 2 more bands than serum More than 2 OCB in CSF & polyclonal pattern in serum Monoclonal band in both serum & CSF Multiple sclerosis Most CNS infections Most Multiple sclerosis Normal individuals Multiple sclerosis CNS lymphoma CNS inflammatory disorders Isoelectric focusing of CSF. Case patient samples are in lanes 4 (CSF) and 4 (serum). The CSF sample is highly positive for oligoclonal bands (arrows). The IgG index was 0.7 (reference interval ) and did not suggest increased intrathecal synthesis. The serum/csf albumin ratio was <9 indicating normal permeability of the blood brain barrier. Controls are indicated on the gel. For comparison, other patients that are negative for oligoclonal banding are shown in lanes 2, 3, and 5.

7 Neuromyelitis Optica (NMO) Aquaporin 4 antibodies by Indirect Immunofluorescence a-binding of serum AQP4-Ab to adult mouse cerebellum as demonstrated by immunohistochemistry. Magnified images show staining of b- the microvasculature, c - the Virchow Robin spaces and d - the pia mater. e g Binding of serum AQP4- Ab to the surface of cultured human embryonic kidney (HEK293) cells transfected with human full length AQP4 (panel e; see panel f for higher magnification) or nontransfected control cells (panel g) Aquaporin 4 IIF - Mosaic with rat cerebrum, cerebellum, transfected HEK cells with aquaporin 4 & non-transfected HEK cells ELISA for IgG aquaporin 4 is also available IgG NMO Rarely seen in SLE, Sjogren syndrome

8 NMDA receptors GAD receptors Autoantibody IIF or blot assay Disease association GAD Cerebellar neuronal cytoplasm, granular positivity Stiff syndrome NMDA (NR1) (NR2 & 3) Mosaic with rat hippocampus & cerebellum, transfected HEK cells with NMDA-NR1 & nontransfected HEK cells Limbic encephalitis Psychiatric lupus VGKC (caspr2,ligi1) Mosaic similar to NMDA in process - under validation Limbic encephaltis

9 Autoantibodies & Nervous system disorders- Autoantibody IIF or blot assay Disease association Myelin Myelin associated glycoprotein (MAG) White matter granular positivity in cerebellum, nerves with diffuse cylinders White matter granular positivity in cerebellum, nerves with central clearing & peripheral granularity unclear IgM gammopathy associated, Guillian Barre Syndrome Line Blot Assay : -For antibodies against Gangliosides Ganglioside GM1 Euroline blot assay Guillian barre syndrome, multifocal motor neuropathy, chronic inflammatory demyelinating polyneuropathy Ganglioside GQ1b Euroline blot assay Miller Fisher syndrome Neurofilament Neuroendothelium Non-medullated nerves Few isolated thin fibrils in white matter in cerebellum Seen inside the blood vessels, can cause interpretative problems in NMO Positivity in only intestinal meyenteric plexus Dysglobulinaemia with polyneuropathy Unclear Chronic inflammatory bowel diseases

10 Anti- neuronal antibodies Paraneoplastic syndromes These antibodies can occur upto 5 years before the appearance of detectable tumour Associated ANA can interfere in interpretation & Blot assay recommended in such cases to confirm antineuronal antibodies Anti neuronal antibody IIF Disease association ANNA-1 (anti-hu) Cerebral & cerebellar neuronal nuclei, intestinal meyenteric plexus Subacute sensory neuronopathy SCLC, neuroblastoma ANNA-2(Anti- ri) Cerebral & cerebellar neuronal nuclei, Absent intestinal meyenteric plexus Opsoclonus-myoclonus syndrome- Breast CA, SCLC Anti- yo (anti-purkinje cell) Cerebellar Purkinje cells cytoplasm Diploplia,dysarthria,tremors- ovary, breast,uterus CA Anti- tr(anti-purkinje cell) Anti - amphyphysin Anti CV2 Cerebellar Purkinje cells cytoplasm & dendritic processes Cerebellar neuronal cytoplasm- granular positivity Cerebellar neuronal cytoplasm- weak diffuse positivity Exact association unclear Stiff person syndrome -SCLC, breast CA SCLC, thymoma Anti - Ma Cerebellar neuronal nucleoli positive Brain stem encephalitis Anti Ma1- breast CA Anti Ma2/Ta- testis tumours

11 Anti- neuronal antibodies Indirect Immunofluorescence: Primate Cerebellum: Antibodies against GAD Yo (top), Line Blot Assay : - For antibodies seen in Paraneoplastic syndromes Against Hu and Ri (middle). Peripheral nerves: Antibodies against myelin and MAG (bottom).

12 CNS Infections CSF Pathogen Specific IgG

13 Neuromuscular disorders Neuromuscular junction disease is a condition where the normal conduction through the neuromuscular junction fails to function correctly. Post synaptic - In myasthenia gravis, the End Plate Potential (EPP) fails to effectively activate the muscle fiber due to an autoimmune reaction against acetylcholine receptors, resulting in muscle weakness and fatigue. Most commonly by auto-antibodies against the acetylcholine receptor. It has recently been realized that a second category of gravis is due to auto-antibodies against MuSK. Pre synaptic In Lambert-Eaton myasthenic syndrome, is usually associated with presynaptic antibodies to the voltage-dependent calcium channel. These autoantibodies namely ACRAB, MUSK & VGCC can be tested in serum by immunoprecipitation reaction using Radioimmunoassay (RIA) technique

14 Myositis serum markers

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