What is the Impact of the Antibody Response to Glycan Alpha-Gal in Guillain-Barré Syndrome Associated with SARS-CoV-2 Infection?

There are several reports of the onset of Guillain-Barré syndrome (GBS) symptoms in COVID-19 patients. Previously, we reported that reduction in anti-α-Gal IgE, IgM and IgG antibody titers and alteration of anti-α-Gal antibody isotype composition correlated with COVID-19 severity. In this case study, we aimed to compare the anti-α-Gal antibody response in COVID-19 and GBS patients. The levels of anti-α-Gal IgE, IgM, IgG and IgA were measured by ELISA in the sera of GBS and COVID-19 patients. Patients diagnosed with GBS showed an increase in anti-α-Gal IgM when compared to healthy individuals and COVID-19 patients. The levels of anti-α-Gal IgA were significantly higher in COVID-19 patients. No significant differences were observed in the levels of IgE and IgG between GBS and COVID-19 patients. Profile of anti-α-Gal antibody isotypes revealed a higher representation of anti-α-Gal IgM and IgG among GBS and COVID-19 patients, respectively. Remarkably, anti-α-Gal IgM was also highly represented in SARS-CoV-2 positive patients suffering GBS. Despite the limited number of cases included in the study, we suggest that anti-α-Gal IgM and IgA responses are differentially regulated in GBS and COVID-19 patients, which could reflect the disparate etiologies of these diseases. A possible association between high anti-α-Gal IgA in GBS and COVID-19 severity is proposed.