sIgA is more than just a first line of defense, it is the beginning of priming of the rest of the entire systemic immune system.
Originally it was thought that sIgA was merely a barrier. An important barrier, one that comprises 80-90% of our overall immune function. sIgA lines any area of the body that interfaces with outside world. It does not merely function as a barrier, but also as the first touchpoint for ongoing immune conversations, not just locally but systemically as well.
sIgA circulates into immune cells that line the gut, or GALT. Peyer’s patches, part of this network, receive queues from the relative amount of sIgA that is present. When sIgA goes down, this changes how the systemic immune system responds. For example, lower levels of sIgA will cause more immune confusion, resulting in higher IgG titers to foods. Even when the food is removed, if the bodies’ first-line defense is down (sIgA), titers will remain higher for a longer period of time as the body works to compensate for its normal, first-line immune support, being compromised.
Also, when sIgA is low, the body begins to treat commensal organisms as pathogens. The body realizes that immune support is down, and becomes more reactive, assuming that maybe even a commensal organism is now the reason for decreased level of sIgA. Remaining immune cells will create more oxidative stress in response to commensal pathogens and the body can get worse from the immune system being overly activated to commensal organisms and through immune confusion to foods or other environmental allergens.
sIgA also works to trap pathogens, and flush them downstream, and out of the body. Without sIgA, not only is a pathogen less likely to be trapped, but also less likely to be moved out of the body.
sIgA also communicates with dendric cells helping them to be primed and commit to an identity. Exhaustion of sIgA will cause dendritic cells to move in a more inflammatory direction, further skewing immune response.
sIgA helps the rest of the immune system know what it is up against, and how aggressive it needs to be. Low levels of sIgA shift systemic immune response to become more inflammatory. sIgA is not merely 80% of our immune system, but the first signal that lets the rest of the immune system know how to behave. Understanding levels of sIgA can help us decrease reactions to environmental and food allergies and sensitivities, help protect us from infection, and prevent autoimmunity.
– Dr. Cheryl Burdette, ND.