2421. Package # 364 (Coeliacs disease)

Celiac disease is an autoimmune disorder associated with intolerance to gluten – a protein found in wheat, rye, barley, and oats. It is a common condition that develops in genetically predisposed individuals and most often manifests as gluten-sensitive enteropathy.

Based on clinical features, the main forms of celiac disease are distinguished as follows:

• typical disease – gastrointestinal symptoms predominate;
• atypical (extraintestinal) disease – accompanied by other systemic disorders but with minimal gastrointestinal manifestations;
• asymptomatic disease – there are no clinical manifestations, but damage to the small intestinal mucosa and positive serological markers are detected;
• latent disease – patients have a genetic predisposition and positive autoimmune markers, but the structure of the mucosa remains unchanged, and symptoms may be absent.

Up to 3% of patients with celiac disease have isolated immunoglobulin IgA deficiency. To prevent errors during the laboratory diagnosis of celiac disease, IgG and IgA antibodies to tissue transglutaminase are tested together with measurement of the serum concentration of immunoglobulin class A.

Celiac disease primarily affects people of European descent and develops in 10–20% of first-degree relatives. This condition may be congenital or develop against a background of autoimmune inflammation. The underlying mechanism of celiac disease involves increased sensitivity of intestinal cells to gliadin (a component of gluten), as well as a deficiency of enzymes responsible for its breakdown. As a result, gliadin accumulates in the intestinal lumen. This causes villous atrophy and impaired absorption.

IgA and IgG antibodies to tissue transglutaminase are directed against the enzyme transglutaminase, which is involved in the biochemical conversion of gliadin. Under the influence of tissue transglutaminase, gliadin is converted into a more immunogenic peptide, which triggers and sustains an inflammatory process in the intestinal mucosa that eventually leads to its atrophy.

Total IgA antibodies are an important factor in the local defense of mucous membranes. They bind to microorganisms and prevent their penetration from external surfaces into deeper tissues, and enhance phagocytosis of antigens by activating the alternative complement pathway. IgA deficiency is often associated with autoimmune pathologies – enteropathies accompanied by protein loss. In celiac disease, immunoglobulin A (IgA) deficiency occurs 10–15 times more frequently than in healthy individuals. Therefore, patients with IgA deficiency and celiac disease may have false-negative serological results for IgA antibodies to tTG.

The use of a comprehensive test – Panel No. 364 “Celiac Disease” – will increase the reliability of serological methods for detecting symptomatic and asymptomatic forms of the disease, regardless of whether IgA levels are normal or deficient.

The panel is recommended for individuals with symptoms of celiac disease (recurrent vomiting, diarrhea, growth retardation in children; abdominal pain, anemia, epilepsy, atopic dermatitis, angular cheilitis, aphthae, Duhring–Brocq dermatitis herpetiformis, signs of vitamin deficiency – visual impairment, neuropathy, osteopenia, tetany, increased bleeding tendency, amenorrhea, infertility, and impotence in adults).

It is used as an initial screening test for individuals with suspected celiac disease (positive family history); in groups at increased risk of developing celiac disease (type 1 diabetes mellitus, Hashimoto’s autoimmune thyroiditis, systemic connective tissue diseases, and Down, Turner, and Williams syndromes); during preparation for endoscopic examination; and for monitoring the effectiveness of a gluten-free diet.

• Venous blood

In order to exclude factors that may affect the test results, we recommend to follow the preparation rules: