title: Dynamic changes of IgG subtypes of thyroid peroxidase antibody in patients with postpartum thyroiditis.
abstract: OBJECTIVE
  To clarify dynamic changes of IgG subtypes of thyroid peroxidase antibody (TPOAb) during the first postpartum year in Chinese patients diagnosed with postpartum thyroiditis (PPT).
  
  
  METHODS
  We retrospectively collected serum samples before and 3, 6, 9 and 12 months postpartum from 58 PPT patients. Levels of TPOAb and its IgG subtypes were examined by ELISA.
  
  
  RESULTS
  Titers of total TPOAb and its IgG subtypes were lowest before delivery in PPT patients. Following delivery, titers of total TPOAb increased. Concentrations of IgG1 and IgG4 subtypes increased for 3 months postpartum, then became stable. Concentrations of the IgG2 subtype increased gradually until 9 months postpartum. Concentrations of the IgG3 subtype reached a peak at 6 months postpartum and remained at a high level thereafter. In PPT patients with an episode of hypothyroidism, levels of total TPOAb and of the IgG subtypes as well as the IgG1/IgG4 ratios were significantly higher than those in patients with an episode of hyperthyroidism and normal controls. Correlations between titers of TPOAb and thyroid-stimulating hormone levels (positive) and free T(4) levels (negative) were seen 6 months postpartum.
  
  
  CONCLUSIONS
  TPOAb is related to thyroid injury and the IgG1 subtype of TPOAb may play a major role in the damage of the thyroid in PPT.
authors.affiliation: Department of Endocrinology and Metabolism and Institute of Endocrinology, First Affiliated Hospital of China Medical University, Shenyang, Liaoning, 110001 PR China.
authors.forename: Di
authors.initials: D
authors.lastname: Teng
authors.forename: Chenyang
authors.initials: C
authors.lastname: Li
authors.forename: Ying
authors.initials: Y
authors.lastname: Teng
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Ouyang
authors.forename: Yushu
authors.initials: Y
authors.lastname: Li
authors.forename: Weiping
authors.initials: W
authors.lastname: Teng
mesh_terms: D002681:China; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000097:blood / Q000276:immunology*; D007453:Iodide Peroxidase / Q000097:blood / Q000276:immunology*; D049590:Postpartum Period; D050032:Postpartum Thyroiditis / Q000201:enzymology / Q000276:immunology*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric
chemical_list: D007132:Immunoglobulin Isotypes; D007453:Iodide Peroxidase