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Neuropathy with IgM anti-MAG antibodies

Histochemistry Toluidine blue Ultrastructure   Wide spacing

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stain

Anti-MAG antibodies: Nerve Histology
  Myelinated Axons: Reduced numbers
  No inflammation
  Subperineurial edema: Mild

VvG stain

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H&E stain

Anti-MAG antibodies: Nerve Histology
  Myelinated Axons: Reduced numbers

VvG stain

Gomori trichrome stain

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Neurofilament stain

Anti-MAG antibodies: Nerve Patholology
  Larger Axons (Above): Severely reduced #s
  Small axons (Above): Reduced #s, but Relatively preserved
  Non-myelinating Schwann cells (Below): Diffusely distributed in endoneurium

NCAM stain

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NCAM (Green) + P0 (Red) stain

Non-Myelinating Schwann (Remak) Cells: Abnormal
  Most Schwann cells have a denervated phenotype: Express both NCAM & P0
Abnormal Myelin
  Myelin sheaths contain NCAM as well as P0

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Büngner band cells
  Peripheral nerve Schwann cells with no asociated axon

Ultrastructure

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NCAM (Green) + MBP (Red) stain stain

Abnormal Myelin
  Myelin sheaths contain NCAM as well as MBP

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VvG stain

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No endoneurial C_5b-9 staining

C5b-9 stain

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Scattered endoneurial histiocytes

Acid phosphatase stain

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No Demyelination
  All larger axons have surrounding P0 stained myelin

Neurofilament (Green) + P0 (Red) stain

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Toluidine blue stain

Myelin sheaths around remaining larger axons: Often have irregular shapes

Toluidine blue stain

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Toluidine blue stain

Myelin sheaths around remaining larger axons: Often have irregular shapes & staining

Toluidine blue stain

Toluidine blue stain

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MAG Neuropathy: Nerve & Myelin Ultrastructure

From: R Schmidt

Myelin sheaths may have abnormal folded shapes

From: R Schmidt

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MAG neuropathy: Thin myelin sheath surrounded by Schwann cell processes

From: R Schmidt

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From: R Schmidt

MAG neuropathy: Myelin wide spacing & Irregular shaped layers

From: R Schmidt

From: R Schmidt

Myelin Wide Spacing

From: R Schmidt

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From: R Schmidt

MAG neuropathy: Myelin Wide Spacing with separation of layers of compact myelin

From: R Schmidt

From: R Schmidt

MAG neuropathy: Myelin Wide Spacing with separation of layers of compact myelin

From: R Schmidt

From: R Schmidt

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MAG neuropathy: Other Pathology

From: R Schmidt

Axon Atrophy with Relatively thick myelin sheath

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From: R Schmidt

Schmidt-Lanterman clefts
  Irregular structure

From: R Schmidt

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From: R Schmidt

Myelin Layers
  Incompletely compacted

From: R Schmidt

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3/3/2024