title: CTLA-4 gene polymorphisms and their influence on predisposition to autoimmune thyroid diseases (Graves' disease and Hashimoto's thyroiditis).
abstract: BACKGROUND
  Autoimmune thyroid disease (AITD) is associated with both genetic and environmental factors which lead to the overactivity of immune system. Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) gene polymorphisms belong to the main genetic factors determining the susceptibility to AITD (Hashimoto's thyroiditis, HT and Graves' disease, GD) development. The aim of the study was to evaluate the relationship between CTLA-4 polymorphisms (A49G, 1822 C/T and CT60 A/G) and HT and/or GD in Polish patients.
  
  
  METHODS
  Molecular analysis involved AITD group, consisting of HT (n=28) and GD (n=14) patients, and a control group of healthy persons (n=20). Genomic DNA was isolated from peripheral blood and CTLA-4 polymorphisms were assessed by polymerase chain reaction-restriction fragment length polymorphism method, using three restriction enzymes: Fnu4HI (A49G), BsmAI (1822 C/T) and BsaAI (CT60 A/G).
  
  
  RESULTS
  Statistical analysis (χ(2) test) confirmed significant differences between the studied groups concerning CTLA-4 A49G genotypes. CTLA-4 A/G genotype was significantly more frequent in AITD group and OR analysis suggested that it might increase the susceptibility to HT. In GD patients, OR analysis revealed statistically significant relationship with the presence of G allele. In controls, CTLA-4 A/A genotype frequency was significantly increased suggesting a protective effect. There were no statistically significant differences regarding frequencies of other genotypes and polymorphic alleles of the CTLA-4 gene (1822 C/T and CT60 A/G) between the studied groups.
  
  
  CONCLUSIONS
  CTLA-4 A49G polymorphism seems to be an important genetic determinant of the risk of HT and GD in Polish patients.
authors.affiliation: Department of Molecular Bases of Medicine, 1  Chair of Internal Diseases, Medical University of Lodz, Poland.
authors.forename: Dorota
authors.initials: D
authors.lastname: Pastuszak-Lewandoska
authors.forename: Ewa
authors.initials: E
authors.lastname: Sewerynek
authors.forename: Daria
authors.initials: D
authors.lastname: Domańska
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Gładyś
authors.forename: Renata
authors.initials: R
authors.lastname: Skrzypczak
authors.forename: Ewa
authors.initials: E
authors.lastname: Brzeziańska