Profiling Antibody Reactivity to Gut Microbes in ME/CFS Patients.

The gut microbiome plays a vital role in physiological functions including metabolism, immune regulation, and gut-brain communication. Alterations in gut microbe makeup and function, termed microbial dysbiosis, are associated with various metabolic, inflammatory, and neurological disorders. Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) patients often display gut microbial dysbiosis and increased intestinal barrier permeability ("leaky gut"). This "leaky gut" allows for microbial products and toxins, such as lipopolysaccharides (LPS), to enter the bloodstream, triggering systemic inflammation and immune dysregulation. ME/CFS patients exhibit altered immune responses, including production of antibodies reactive with gut microbial antigens, although the significance of these antibodies in promoting pathogenic or protective immune responses remains unclear. This chapter outlines methodologies for quantifying antibody reactivity to intestinal microbes and identifying stool-bound IgG in ME/CFS patients and healthy same household controls, to further investigate the role of anti-microbial IgG in ME/CFS pathogenesis.