A 30-year-old woman presents with ascending flaccid paralysis 10 days after a gastroenteritis. CSF shows albumin-cytological dissociation (protein 2.4 g/L, cells 2/mm³). NCS shows absent F-waves and prolonged distal motor latency. Which serological finding is most commonly associated with axonal GBS (AMAN subtype)?
- A Anti-GQ1b IgG antibodies
- B Anti-GM1 or anti-GD1a IgG antibodies ✓
- C Anti-sulfatide antibodies
- D Anti-HMGCR antibodies
Correct answer: B. Anti-GM1 or anti-GD1a IgG antibodies
Explanation
Acute motor axonal neuropathy (AMAN), a pure motor axonal variant of GBS, is strongly associated with anti-GM1 and anti-GD1a IgG antibodies, particularly following Campylobacter jejuni infection. Molecular mimicry between lipooligosaccharides of C. jejuni and gangliosides on axonal membranes is the proposed mechanism. Anti-GQ1b IgG is associated with Miller Fisher syndrome (ophthalmoplegia, ataxia, areflexia). Anti-HMGCR antibodies are seen in immune-mediated necrotizing myopathy.
Reference: Harrison's Principles of Internal Medicine, 21st ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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