Secretory IgA

Randomized controlled trials are cited as showing probiotics increase SIgA. Secretory IgA is the predominant mucosal immunoglobulin in the gut. Secretory IgA is described as a first-line defense across mucosal surfaces. Secretory IgA can bind invading microorganisms and antigenic proteins such as gliadin in the intestinal lumen. Gut SIgA status is presented as a signal that can correspond to systemic immune state. Food antigen tolerance depends partly on epithelial and immune cell maturation that is largely determined by commensal microbiota. Elevated secretory IgA can be caused by acute infections, acute stress, food sensitivities, environmental insults, celiac disease, or colon cancer. Common causes of low secretory IgA include decreased commensal bacteria, chronic infections, chronic stress, and chronically decreased gut barrier function. Depleted SIgA can impair mucosal discrimination between commensal bacteria and pathogens. The recommended clinical approach for elevated SIgA is to identify and address the root cause trigger.