ANALYSIS OF THE FREQUENCY AND FEATURES OF THE CLINICAL COURSE OF AUTOIMMUNE THYROIDITIS IN COMBINATION WITH CELIAC DISEASE

Abstract

The aim of the study was to determine the frequency and features of the clinical course of autoimmune thyroiditis (AIT) in combination with autoimmune pathology of the small intestine (coeliac disease, gluten intolerance without celiac disease).

Materials and methods. 173 patients (three age groups: I – 5-20, II – 21-45, III – 46-60 years) with an antithyroid peroxidase (anti-TPO) antibody level in the blood over 600 μIU/mL were examined: n=35 men/138 women. Thyroid status was assessed by the levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3). Ultrasound diagnostics was also used to visualize the thyroid gland (TH). To verify celiac disease, anti-tissue transglutaminase IgA antibody (anti-tTG IgA) (U/mL), anti-tissue transglutaminase IgG antibody (anti-tTG IgG) (U/mL), anti-gliadin (deaminated peptides) IgA antibody (anti-G IgA) (U/mL), anti-gliadin IgG antibody (anti-G IgG) (U/mL) and serum immunoglobulin A (IgA) levels (g/L) were determined using the immunoturbidimetric method on the “ELIA Phadia” analyzer. Statistical processing of the results was performed using the Package for Social Sciences v.19.0 (SPSS Inc., Chicago, Il, USA).

Results and conclusions. It was found that 32.4% of patients with AIT of all age groups have a high titer of anti-tTG and/or anti-G. During screening examination in the group of patients with AIT under 20 years of age, a positive titer of anti-tTG IgG was detected in 14.3%, anti-G IgG in 17.9%, in the group of patients aged 21-45 years - in 10.5 and 27.6%, respectively; in the group of patients aged 46-60 years - in 5.8 and 23.2%, respectively. Simultaneously positive titer of IgG and IgA anti-tTG and anti-G is observed in 2.3% of patients, which, in the presence of pronounced activity of antithyroid immunity, moderate hypothyroidism, erased gastrointestinal symptoms and other nonspecific extraintestinal clinical signs, allows establishing the diagnosis of "Celiac disease" with a high degree of probability. In other cases, if only an elevated titer of anti-G IgG is present, “Gluten intolerance without celiac disease” is diagnosed. Given the low frequency (2.89%) of high titers of anti-tTG and anti-G IgA, their use as diagnostic criteria in screening patients with AIT is not advisable. In the presence of combined polyglandular autoimmune endocrine pathology in combination with other autoimmune non-endocrine diseases, it is necessary to diagnose celiac disease using anti-tTG and anti-G of both IgA and IgG classes. The established linear positive strong correlation (r= 0.83, p=0.01) between the levels of anti-G IgG and anti-TPO proves that with high titers of anti-TPO in patients with AIT, the severity of the immune response to the pathological effect of gluten increases.