IgA Antibody Assessment Panels

The Advantage of IgA Testing:

US BioTek’s in-house studies show that 90-95% of blood samples negative for specific-IgE, 70-85% of these test positive for specific-IgG. Blood samples negative for both specific-IgE and IgG, 30-40% test positive for specific-IgA.

IgA antibody testing provides additional information to identify possible suspect food or inhalant triggers.

What We Know:

• Impairment of humoral and mucosal immune responses, or oral tolerance, plays a contributing role to the pathogenesis of disease. The breakdown of this tolerance may result in abnormal processing of food proteins in the gut resulting in pro-inflammatory food antigen handling.

• Research studies suggest elevated serum antibodies, IgE, IgG or IgA to food proteins are markers of this immune intolerance. For example, elevated IgA antigliadin is a proven useful marker of the immune reaction in the small intestine triggered by gluten, in celiac disease.

The immunological trigger effects of specific-IgA antibodies merit close consideration for the screening and management of chronic inflammatory disease conditions where there is a suspected loss of oral tolerance.

IgA represents a primary immune reaction. The half-life is about 5-6 days, compared to IgG which is about 20-24 days, and indicative of an ongoing immune reaction.  The assessment of the both antibodies offers a comprehensive picture.

IgA antibodies provide early defense against many antigens. IgA in the form of secretory IgA, sIgA, is produced from initial exposure to antigen. It represents local or mucosal immunity. sIgA binds and excludes antigen present in the intestinal tract, preventing excessive systemic absorption, for example, food peptides, bacteria, viruses, protozoa and fungi; proteins that are normally restricted to the intestinal tract.

IgA antibody is found in many mucous secretions other than that of the gut for the same purpose of immune exclusion including saliva, tears, respiratory and genitourinary tracts.

It is generally thought that serum of IgA- deficient individuals  may contain increased amounts of IgG subclass antibodies in the form of immune complexes to a wide variety of food antigens (casein, bovine immunoglobulin, bovine albumin, a-lactalbumin, chicken ovalbumin, gliadin) simply because of the potential compromised first line of defense that secretory IgA offers.

On the other side of the coin, serum of IgA excess subjects (e.g.: IgA-mediated autoimmune Henoch-Schonlein Purpura) may contain increased amount of IgA subclass antibodies in the form of immune complexes to a wide variety of food antigens, also suggesting globally increased antigen absorption from compromised mucosal integrity. Pro-inflammatory antigen handling arises due to a breach in homeostatic mechanisms/break of oral tolerance to food with immunological hyperactivation.

Generally, human sera contains relatively low levels of IgA compared to IgG because more than half of the IgA produced does not enter circulation but is directly and selectively transported to external secretions –  secretory IgA (IgA dominant in external secretions; IgG dominant in plasma).

IgA does not bind C1q or activate the classical complement pathway as does IgG. The concept that IgA activates the alternate complement pathway is met with conflicting results - but may under pathological circumstances due to aberrant synthesis, for example, disrupting conformational integrity and contributing to inflammatory conditions.

Unfortunately there is no hard and fast rule on when to order IgG vs. IgA or both. Both IgA and IgG may be present in a variety of chronic inflammatory disorders.

Many of the references on food-specific IgA testing are in regards to Celiac/Gluten sensitivity, as this is one of the more popularly studied conditions.

A preferential increase in serum antigliadin IgA has been demonstrated in gut diseases like Celiac, Crohn’s, Ulcerative Colitis in addition to Rheumatoid Arthritis, Bergers’ disease and Henoch-Schonlein Purpura (HSP). Antigliadin IgA is considered a marker of mucosal damage in childhood celiac disease. The presence of IgA-gliadin immune complexes in serum of children with HSP suggests gut mucosal alterations with an increase in intestinal permeability. Food specific IgA has been demonstrated in IgA nephropathy for reasons yet unclear (e.g.: possible IgA immune regulatory abnormality, hepatic clearance defect).

IgA - Available for Serum or Whole Blood from Finger Stick

96 Asian Food

96 General Food

96 Vegetarian Food

16 Vegetarian Item add-on

24 Herb + 24 Spice

16 Inhalant

Other Panels

IgE Antibody Assessment

IgG Antibody Assessment

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