Neuromuscular

Home, Search, Index, Links, Pathology, Molecules, Syndromes,
Muscle, NMJ, Nerve, Spinal, Ataxia, Antibody & Biopsy, Patient Info


AUTOANTIBODIES IN CHRONIC MOTOR SYNDROMES

Indications: Measurement of anti-GM1 antibodies
Interpretations: Positive results
Laboratory standards
Antibody patterns: Specificity for motor neuropathies
Prevalence of anti-GM1 antibodies in MMN
  detected in different laboratories
Anti-GM1 antibodies in therapy: Guidelines
Anti-GM1 ganglioside antibodies: Summary of indications
Indications
Lower motor neuron syndromes
Motor neuropathy: Chronic; Acute
Clinical features
  Predominantly motor
  Distal; Asymmetric
Likelihood of positive test:
  Onset
    Chronic: Slow progression
    Acute: Diarrhea prodrome
    Upper extremity: Often
  No upper motor neuron signs
  No prominent sensory changes
  Motor conduction block
Treatment follow-up
  Document sufficient cytoxan
    Best prognosis: Anti-GM1
      titers by > 70%

Lab standards: IgM vs Co-GM1
Sensitivity for MMN: 45%
Specificity in clinical use: > 98%

Lab standards: IgG vs GM1
Clinical specificity
  > 90%: Acute motor neuropathy
+ Results
Specific ELISA binding
  IgM vs Co-GM1 or NP-9 > 2,000
  IgG vs GM1 > 2,000

Clinical correlations
  IgM vs Co-GM1+
    Motor neuropathy: Chronic
      45% Sensitivity
      99% Specificity vs ALS
  IgG vs GM1 +
    Motor neuropathy: Acute
      50% sensitivity
      90% specificity

Interpretation
Diagnosis
  Dx of immune neuropathy
    Distinguish MMN vs CIDP & ALS
Prognosis: Not ALS;
  Slow progression
Treatment
  Cytoxan or HIG often useful
  Prednisone not useful
Follow-up: Cytoxan Rx
  anti-GM1 titer ? relapse



Prevalence of IgM antibodies to GM1 ganglioside in MMN detected by different laboratories1

Laboratory IgM vs GM1 in MMN:
Prevalence
Sadiq 1990 (Columbia)1 33%
Adams 1991 (Switzerland)2 30%
Specialty Lab (1996)3 20% or less
Mayo Clinic (Taylor 1996)4 50%
Washington University 5, 6, 7, 9 45%



I. Clinical Indications for Measurement of Serum anti-GM1 7, NP-9 8 & NS6S 9 Antibodies

II. Patterns of Antibody Binding with Specificity for Motor Neuropathies

III. Testing Laboratory Standards


IV. Interpretations of Positive Results

V. Guidelines During Cyclophosphamide Therapy


Go to Motor Syndromes: Differential Diagnosis
Go to Demyelinating Neuropathies
Go to Motor Syndromes: Treatment
Go to Diagnosis and treatment of motor neuropathies
Go to Anti-MAG Antibodies
Return to Neuromuscular Home Page



REFERENCES
1. Neurology 1990;40:1067-1072
2. J. Neuroimmunol 1991;32:223-230
3. Unpublished "in house" data. Phone Communication 1996
4. Neurology 1996;47:951-955
5. Ann Neurol 1990;27:316-326
6. Muscle & Nerve 1994;17:100-104
7. Neurology 1997;49:1289-1292; Neurology 2000;54: 2353-2354
8. Neurology 1997;48:1104-1106
9. J Neurol Neurosurg Psychiatry 2010;81:726-730

4/15/2013