- Sample required: 1 tube with 4 ml of saliva, 1 spun SST tube with serum decanted
- Lab reporting time: 4 - 6
- business days
Overview
This screen uses serum to assess total IgA; IgA and IgG to gliadin, a peptide found in gluten; and anti-transglutaminase IgA, a marker for celiac disease within the humoral immune compartment. It also uses a salivary sample to assess the level of secretory immunoglobulin A (sIgA) and the level of salivary IgA to gliadin within the mucosal immune compartment. This test is designed to assess whether an individual is celiac (overt symptoms) or has sub-clinical gluten intolerance (non-symptomatic, that is without obvious GI symptoms).
Physiology
Gliadin is found in wheat, barley, couscous, semolina, triticale, rye, oats (unless specified), kamut, orzo, and spelt. One can have a genetic predisposition to immunologic sensitivity to gliadin. This sensitivity can be manifested as mucosal inflammation of the gastrointestinal tract. Such inflammation can remain subclinical, and persist for decades. Gradually the inflammation leads to abnormal mucosal physiology, and eventually the involved tissue compensates morphologically and becomes disorganized. Intestinal villi shorten; microvilli disappear; and crypt hyperplasia occurs. The disappearance of microvilli signals the inability to transport to, and absorb from, the lumen. The crypts may degenerate into closed pockets deep within the mucosa, trapping luminal contents within those pockets.
The immediate consequences include the malabsorption of all foodstuffs and to a lesser extent fluids. Eventually, intestinal pH becomes abnormal and its characteristic range of fluctuation decreases. Maldigestion follows, and pathogens (bacteria, parasites, yeasts, fungus, etc.) can invade the lumen with relative impunity, become established, and proliferate. The continuing cycle is that of an increasing cascade of intestinal compensations and dysfunction, leading to chronic degenerative disease.
Clinical Aspects
TOTAL SERUM IgA : Total serum IgA is used to qualify the IgA levels for anti-gliadin and anti-transglutaminase and to rule out compromised systemic immunity. Individuals with Selective IgA deficiency may have a clinical or sub-clinical gluten sensitive enteropathy (GSE) with anti-gliadin IgA and anti-transglutaminase IgA reported within normal ranges.
ANTI - GLIADIN ANTIBODY, IgA : Gliadin IgA is an enzyme-linked immunosorbent assay (ELISA) for the detection of Gliadin IgA antibodies in human serum. Detection of these antibodies is an aid in the diagnosis of certain gluten sensitive enteropathies such as celiac disease and herpetiformis. Celiac disease or gluten sensitivity enteropathy is a chronic condition whose main features include inflammation and characteristic histological “flattening” of intestinal mucosa resulting in a malabsorption syndrome.
ANTI-GLIADIN ANTIBODY, IgG : Gliadin IgG is an enzyme-linked immunosorbent assay (ELISA) for the detection of Gliadin IgG antibodies in human serum. Detection of these antibodies is an aid in the diagnosis of certain gluten sensitive enteropathies such as celiac disease and herpetiformis. Celiac disease or gluten sensitivity enteropathy is a chronic condition whose main features include inflammation and characteristic histological “flattening” of intestinal mucosa resulting in a malabsorption syndrome.
Measuring both IgA & IgG provides a higher degree of detection.
ANTI-TRANSGLUTAMINASE ANTIBODY, IgA : Human tissue transglutaminase is an enzyme-linked immunosorbent assay (ELISA) for the detection of IgA antibodies to tissue transglutaminase (endomysium) in human serum. Detection of these antibodies is an aid in diagnosis of certain gluten sensitive enteropathies such as celiac disease and dermatitis herpetiformis. Celiac disease and dermatitis herpetiformis, two recognized forms of gluten sensitive enteropathy (GSE) are characterized by chronic inflammation of the intestinal mucosa and flattening of the epithelium or positive “villous atrophy”. Intolerance to gluten (gliadin), the protein found primarily in grains such as wheat, rye and barley causes GSE. Patients with celiac disease may suffer from diarrhea, gastrointestinal problems, anemia, fatigue, psychiatric problems and other diverse side effects or they may be asymptomatic. Dermatitis herpetiformis is a skin disease associated with GSE. All GSE patients have an increased risk of lymphoma. A gluten-free diet controls GSE and associated risks.
SALIVARY ANTI-GLIADIN ANTIBODY, IgA : An elevation in this antibody is evidence of mucotoxic reaction to the gliadin polypeptide within the digestive tract. Depending on the overall health of the mucosal barrier and whether or not the gut is “leaky”, gluten sensitive enteropathies can show up either in the mucosal compartment or the general circulation or both. It is vital to check salivary (mucosal) IgA to gliadin to definitively rule in or rule out gluten sensitive enteropathy, clinical or sub-clinical. The salivary anti-gliadin antibody helps to detect earlier stages (sub-clinical) cases of gluten intolerance, while positive humoral antibodies indicate a more advanced and severe gliadin intolerance.
TOTAL SECRETORY IgA (sIgA) : In order to evaluate how well the mucosal barrier first line immune defense is working, it is necessary to look at total secretory IgA. This measurement is used to validate the relevance of the salivary anti-gliadin, IgA result. Suppressed levels of total sIgA may relate to a suppressed IgA anti-gliadin response, even though gluten sensitive enteropathy is present.
Humoral and mucosal immunology (serum and salivary antibodies) yields the highest diagnostic accuracy.
Conditions Assessed
Conditions that may be assessed include celiac disease, sub-clinical gluten intolerance and overall immune system viability. Sequelae include maldigestion and malabsorption of proteins, carbohydrates, and fats, which in turn can lead to a variety of chronic degenerative disorders, including autoimmune, cardio vascular disease and cancer.
Logical Sequence of Testing
The logical sequence of using this test as an initial or a follow-up test is determined by a variety of individual considerations, including the patient's chief complaint, the array of signs and symptoms, the chronicity of the condition, the tests previously taken, and the judgment of the practitioner. Technical assistance is available from BioHealth Diagnostics' support staff.
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