PHYSIOLOGICAL RESEARCH ISSN 0862-8408  2003 Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic Fax +420 241 062 164 E-mail: physres@biomed.cas.cz http://www.biomed.cas.cz/physiolres Physiol. Res. 52: 79-88, 2003 IgA and IgG Antigliadin, IgA Anti-tissue Transglutaminase and Antiendomysial Antibodies in Patients with Autoimmune Thyroid Diseases and Their Relationship to Thyroidal Replacement Therapy J. JISKRA, Z. L˝MANOV`, Z. VAN˝ČKOV` 1 , P. KOCNA 1 Third Medical Department and 1 Department of Clinical Biochemistry, First Medical Faculty, Charles University, Prague, Czech Republic Received June 5, 2002 Accepted June 23, 2002 Summary Celiac disease is a chronic illness of the small bowel caused by gliadin intolerance in genetically predisposed subjects. The aim of this study was to investigate serum levels of IgA and IgG antigliadin antibodies, IgA antiendomysial antibodies, and IgA anti-tissue transglutaminase antibodies in 169 patients with autoimmune thyroid diseases, i.e. chronic thyroiditis and Graves· disease. Antiendomysial antibodies were positive in 2 out of 169 persons (1.18 %), IgA antigliadin antibodies in 15.98 %, IgG antigliadin antibodies in 51.48 %, and IgA anti-tissue transglutaminase in 14.79 %. The prevalence of positivity was higher compared to the 1312 control blood donors described in our previous study (VančkovÆ et al. 2002) (p<0.05). Patients with chronic thyroiditis treated with a high replacement dosage of levothyroxin (125-200 g daily) had higher serum levels of IgA antigliadin antibodies in comparison with patients treated with a lower dosage (50-100 g daily) (medians: 13.00 vs. 19.69, p=0.033). We found a negative correlation of IgA anti-tissue transglutaminase antibodies and total calcium serum levels (r = 0.480, p=0.0236, n=22). We can conclude that in persons with autoimmune thyropathy there is a high prevalence of positive antigliadin, anti-tissue transglutaminase and antiendomysial antibodies. Latent celiac disease may lead to impaired resorption of therapeutically administered levothyroxine, calcium, or other substances. Key words Celiac disease • Antigliadin antibodies • Thyroid autoimmunity Introduction Celiac disease is a chronic disease of the small bowel caused by gluten intolerance in genetically predisposed people with several features of autoimmunity (TlaskalovÆ et al. 2000): 1) HLA linkage (HLA-DQA1 0501, HLA-DQB1 0201), 2) associated autoimmune diseases as type 1 diabetes mellitus (De Block et al. 2001, Jaeger et al. 2001, Volta et al. 1997), autoimmune thyroid disease (Collin et al. 1994, Counsell et al. 1994, Sategna-Guidetti et al. 1998, Velluzzi et al. 1998, Cuoco et al. 1999, Valentino et al. 1999, Kowalska et al. 2000, Sategna-Guidetti et al. 2001, Volta et al. 2001), polyglandular autoimmune syndrome (Kaukinen et al.