Measure First-Line Immune Defense
The importance of measuring Secretory IgA (SIgA) levels cannot be understated.
SIgA results not only reveal a patient’s ability to defend against infections, allergies, and food reactions – they also provide clues into where to go next in the investigation and treatment of health complaints.
This test is available as a standalone test and also available combined with HPA Stress Profiles.
SIgA the Protector
The most recognized function of sIgA includes its role in “immune exclusion” in which it prevents viruses, bacteria, and other antigens from adhering to and penetrating epithelial mucosa. SIgA may also inhibit inflammatory processes that damage the mucosa, and preliminary evidence suggests that it may play a role in inducing an antigen specific immune response by a non-inflammatory mechanism.
In addition, SIgA functions in mucosal immunity and intestinal homeostasis through mechanisms that have only recently been revealed. In just the past several years, sIgA has been identified as having the capacity to directly quench bacterial virulence factors, influence composition of the intestinal microbiota, promote retro-transport of antigens across the intestinal epithelium to dendritic cell subsets in gut-associated lymphoid tissue, and, finally, to downregulate pro-inflammatory responses normally associated with the uptake of highly pathogenic bacteria and potentially allergenic antigens.
HPA Axis and SIgA
Chronic stress causes the HPA axis to go out of balance and it adversely affects the mucosal immune system by way of negative influences on hormone levels, inflammatory controls, and antibody production. Under chronic stress, sIgA production can be suppressed by even temporary elevations of cortisol. Cortisol and DHEA (steroidal hormone, immune modulators) systemically modulate the production of the immunocytes that produce sIgA.
When cortisol and DHEA values are out of balance, immunocyte production can be suppressed resulting in lowered first-line immunity. Sympathetic flow governs the ability of the immunocytes to release sIgA. Therefore, sympathetic overload (prolonged fight/flight) can result in lowered sIgA production and further compromise immune defense.
The SIgA Lab Test
Using the ELISA testing method, the lab analyzes saliva collected over the course of a single day.
The current established reference ranges for sIgA:
Low: <75.0 μg/ml
Equivocal: 75.0-145.0 μg/ml
High: 145.0-330.0 μg/ml
High levels of sIgA may be an indication of acute stress, intestinal barrier dysfunction, acute oral infection, acute GI infection, heavy smoking, alcoholism, periodontitis, dental plaque accumulation, and/or intestinal barrier dysfunction. In general, high sIgA results point toward the need to rule out active infections which are being fought by the heightened alertness of the immune system.
Low levels of sIgA may be an indication of autonomic nervous system imbalance, chronic stress, damage to the intestinal barrier, chronic GI infections, food intolerance, gliadin intolerance, inflammatory bowel disease, and/or use of anti-inflammatory drugs.
Equivocal levels of sIgA need to be considered in the context of the patient’s overall presentation and available diagnostic data.
SIgA and Therapy
In the case of high sIgA levels, additional testing, as well as lifestyle investigation, need to be considered. Changes to lifestyle, along with addressing the underlying causes of elevated immune response, helps to normalize sIgA levels in many patients. More difficult cases may require additional investigation into hormone, immune, and gastrointestinal function. The therapeutic approach to high sIgA levels generally requires an understanding of why the levels are high to begin with, as confirmed with patient interaction and functional lab testing.
Patients with low sIgA levels will benefit from the recommendations for high sIgA, but are also candidates for dietary supplementation. Common, well-researched substances used to rebuild the mucosal barrier and restore balance to the internal environment include: probiotics, colostrum, l-glutamine, deglycyrrhized licorice root, slippery elm, turmeric, quercetin, biotin, and MSM. Contact BioHealth for product recommendations.