Background: Guillain-Barre syndrome (GBS) is considered as an acute, immune-mediated polyradiculoneuropathy with different clinical phenotypes arising after viral or bacterial infections, vaccination or surgery. However, in 40% of GBS patients the aetiology remains unknown. In this manuscript, we report the occurrence of GBS in a patient bitten by a snake (Vipera aspis) for which a cross-reaction was shown between GM2 ganglioside and glycosidic epitopes of venom proteins.
Methods: The venom of the snake implied in the patient's envenomation was collected. Its composition was characterised by ELISA and SELDI-TOF MS. Cross-reactivities between venom proteins and GM2 gangliosides were identified by Western blot after immunoabsorption of patient's serum with increasing amounts of purified GM2. Enzymatic deglycosylation of the venom was performed to determine the specificity of the patient's serum cross-reaction.
Findings: We proved the absence of neurotoxicity of the viper venom. The patient's serum presented specific cross-reactions with several glycosylated venom proteins. After deglycolysation of these proteins, the patient's serum cross-reactivity was abolished. Furthermore, we compared the immune response to venom proteins of sera from two groups of patients. The first group showed IgM reactivity against GM2 ganglioside associated with GBS, and cross-reacted with venom proteins. The second group presented an IgM reactivity against CMV, without neurological disorders, and reacted with neither venom proteins nor gangliosides.
Interpretation: Our study proved the auto-immunological aetiology of GBS in our patient based on molecular mimicry mechanisms between venom proteins and GM2 ganglioside.
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