NEWER TESTS IN

NEUROLOGY

DR RAJESH V BENDRE

HOD, IMMUNOCHEMISTRY

METROPOLIS, MUMBAI

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

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)

Recent Advances in

Neuroimmunology

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

Multiple Sclerosis An Immunogenetic Disease

MS

Immune Dysregulation

Genetic Predisposition • Twins studies

• HLA-DR2 (DRß1*1501)

(antigen presentation)

• IL-2Ra

• (regulatory T-cells)

• IL-7Ra

(memory T-cells)

Environmental Factors

Demographics/Epidemics

Microbial Agents

EBV

Vitamin D

MS – CSF OCB

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 0.3–0.8) 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.

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

3 OCB in both serum & CSF CSF has at least 2 more bands than serum

Multiple sclerosis Most CNS infections

4 More than 2 OCB in CSF & polyclonal pattern in

serum Most Multiple sclerosis

5 Monoclonal band in both

serum & CSF

Normal individuals Multiple sclerosis CNS lymphoma

CNS inflammatory disorders

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

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 & non-

transfected HEK cells

Limbic

encephalitis

Psychiatric

lupus

VGKC

(caspr2,Ligi1)

Mosaic similar to NMDA in

process - under validation

Limbic

encephaltis

Autoantibodies &

Nervous system disorders-

Autoantibody IIF or blot assay Disease association

Myelin White matter granular positivity in

cerebellum, nerves with diffuse cylinders

unclear

Myelin associated

glycoprotein (MAG)

White matter granular positivity in

cerebellum, nerves with central clearing &

peripheral granularity

IgM gammopathy

associated, Guillian

Barre Syndrome

Ganglioside GM1 Euroline blot assay Guillian barre

syndrome, multifocal

motor neuropathy,

chronic

inflammatory

demyelinating

polyneuropathy

Ganglioside GQ1b Euroline blot assay Miller Fisher

syndrome

Neurofilament Few isolated thin fibrils in white matter in

cerebellum

Dysglobulinaemia

with polyneuropathy

Neuroendothelium Seen inside the blood vessels, can cause

interpretative problems in NMO

Unclear

Non-medullated

nerves

Positivity in only intestinal meyenteric

plexus

Chronic

inflammatory bowel

diseases

Line Blot Assay :

-For antibodies

against

Gangliosides

Anti- neuronal antibodies –

Paraneoplastic syndromes

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) Cerebellar Purkinje cells cytoplasm & dendritic

processes

Exact association unclear

Anti - amphyphysin Cerebellar neuronal cytoplasm- granular

positivity

Stiff person syndrome

-SCLC, breast CA

Anti – CV2 Cerebellar neuronal cytoplasm- weak diffuse

positivity

SCLC, thymoma

Anti - Ma Cerebellar neuronal nucleoli positive Brain stem encephalitis

Anti Ma1- breast CA

Anti Ma2/Ta- testis tumours

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 antibodies –

Indirect

Immunofluorescence:

Primate Cerebellum:

Antibodies against GAD

Yo (top),

Against Hu and Ri

(middle).

Peripheral nerves:

Antibodies against

myelin and MAG

(bottom).

Line Blot Assay :

- For antibodies seen in

Paraneoplastic syndromes

CNS Infections –

CSF Pathogen Specific IgG

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

Myositis – serum markers