title: Thyroglobulin autoantibodies of patients with subacute thyroiditis are restricted to a major B cell epitope.
abstract: BACKGROUND
  Thyroglobulin autoantibodies (TgAb) can develop in patients with subacute thyroiditis (SAT).
  
  
  OBJECTIVE
  Comparison of the epitope pattern of TgAb of patients with SAT, Hashimoto's thyroiditis (HT) [autoimmune thyroid disease (AITD)] and non-toxic multinodular goiter (NTMG) (non-AITD).
  
  
  METHODS
  Serum TgAb from 10 patients with SAT, 45 with HT, and 19 with NTMG were evaluated. Serum TgAb binding to Tg was inhibited by 4 recombinant human TgAb-Fab, recognizing Tg epitope regions A, B, C, and D. The ability of single TgAb-Fab to inhibit the binding of serum TgAb to Tg was evaluated in enzymelinked immunosorbent assay.
  
  
  RESULTS
  Levels of inhibition were different for all TgAb-Fab in the 3 groups of patients. Inhibition by region A TgAb-Fab in SAT [50.5 (30.3-62.5)%] (median and 25th to 75th percentiles) was similar to HT [49.0 (38.0-69.5)%] and significantly higher than in NTMG [25.0 (14.0-37.0)%]; by region B TgAb-Fab in SAT [0.0 (0.0-12.5)%] was significantly lower than in HT [28.0 (9.5-48.0)%] and similar to NTMG [9.0 (4.8-20.5)%]; by region C TgAb-Fab in SAT [9.5 (0.0-25.8)%] were similar to HT [23.0 (9.5-41)%] and NTMG [6.5 (1.7-21.5)%]; and by region D TgAb-Fab in SAT [0.0 (0.0-8.0)%] were lower than in HT [12.0 (1.0-28.5)%] and similar to NTMG [1.0 (0.0-5.0)%].
  
  
  CONCLUSIONS
  The epitope pattern of TgAb of SAT is restricted to the A region that is immunodominant in AITD and non-AITD. In the majority of patients with SAT, the autoimmune phenomena represent a non-specific and transient response to the release of thyroid antigens, rather than the expression of thyroid autoimmunity.
authors.affiliation: Department of Endocrinology, WHO Collaborating Center for the Diagnosis and Treatment of Thyroid Cancer and Other Thyroid Diseases, University of Pisa, Pisa, Italy. latrofaf@libero.it
authors.forename: F
authors.initials: F
authors.lastname: Latrofa
authors.forename: D
authors.initials: D
authors.lastname: Ricci
authors.forename: L
authors.initials: L
authors.lastname: Montanelli
authors.forename: M A
authors.initials: MA
authors.lastname: Altea
authors.forename: A
authors.initials: A
authors.lastname: Pucci
authors.forename: A
authors.initials: A
authors.lastname: Pinchera
authors.forename: P
authors.initials: P
authors.lastname: Vitti
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D018985:Epitopes, B-Lymphocyte / Q000276:immunology*; D005260:Female; D050031:Hashimoto Disease / Q000097:blood / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013954:Thyroglobulin; D013967:Thyroiditis, Autoimmune / Q000097:blood / Q000276:immunology*; D013968:Thyroiditis, Subacute / Q000097:blood / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D018985:Epitopes, B-Lymphocyte; D013954:Thyroglobulin