<prompt> Anti GDlaAIDPASMANAMANFisher syndrome  <response>: Immunopathological studies suggest that the target of immune attack is different in the subtypes of Guillain-Barre syndrome GBS. In acute motor axonal neuropathy AMAN, the attack appears directed against the axolemma and nodes of Ranvier. In acute inflammatory demyelinating polyneuropathy AIDP, the attack appears directed against a component of the Schwann cell. However, the nature of the antigenic targets is still not clear. We prospectively studied 138 Chinese GBS patients and found that IgG anti-GD1a antibodies were closely associated with AMAN but not AIDP. With a cutoff titer of greater than 1:100, 60 of AMAN versus 4 of AIDP patients had IgG anti-GD1a antibodies; with a cutoff titer of greater than 1:1,000, 24 of AMAN patients and none of the AIDP patients had IgG anti-GD1a antibodies. In contrast, low levels of IgG anti-GM1 antibodies 1:100 were detected in both the AMAN and the AIDP forms 57 vs 35, NS. High titers of IgG anti-GM1 1:1,000 were more common in the AMAN form 24 vs 8, NS. Serological evidence of recent Campylobacter infection was detected in 81 of AMAN and 50 of AIDP patients, and anti-ganglioside antibodies were common in both Campylobacter-infected and noninfected patients. Our results suggest that IgG anti-GD1a antibodies may be involved in the pathogenesis of AMAN. 