Anti-sulfatide IgG in Miller Fisher syndrome: Report of two cases

Abstract

Anti-GQ1b IgG is the hallmark biomarker of Miller Fisher syndrome (MFS), an acute neuropathy characterized by ophthalmoplegia, ataxia and areflexia. In contrast, anti-sulfatide IgG is typically associated with chronic neuropathies, and its presence in acute presentations is uncommon. We report two female patients who presented with acute-onset giddiness, imbalance and diplopia. Initial examination showed gait ataxia, reduced reflexes and mild extraocular movement restriction, which progressed over the next few days to near complete ophthalmoplegia, consistent with classic MFS. Both patients had albuminocytologic dissociation on cerebrospinal fluid analysis. Serology showed isolated sulfatide-IgG positivity in the first case, and dual sulfatide-IgG and anti-GQ1b IgG positivity in the second. Both patients received intravenous immunoglobulin (IVIG) and showed marked clinical improvement. These cases suggest that anti-sulfatide IgG, although classically linked to chronic neuropathies, may also be detected in MFS, either alone or in combination with anti-GQ1b. Recognition of nonclassical antibodies may assist in identifying atypical or GQ1b-negative MFS- spectrum presentations and broaden the understanding of its immunological profile.