Analysis of mononuclear cell subsets infiltrated and DR-positive epithelial cells in autoimmune thyroid diseases

Specimens of thyroid tissue from 37 cases of autoimmune thyroiditis (AT), 13 cases of thyrotoxicosis accompanied with thyroiditis (TTOT), and 23 cases of Graves' disease (GD) were analyzed by immunohistochemistry with monoclonal antibodies. The majority of infiltrating mononuclear cells were learnt to be T cells. T+4 cells were abundant in lymphoid follicles and many T+8 cells were noticed in those areas with advanced destruction. B lymphocytes were predominantly located at the germinal centers. Most importantly, DR-positive thyroid epithelial cells were significantly increased with intense lymphocytes infiltration and severe destruction of the thyroid architecture. The percentage of T cell subpopulations, B cells, macrophages were somewhat similar. Anyhow, the increase of total number of infiltrating cells and the extent of inflammatory injury were remarkable in GD, TTOT and AT. The results support the idea that some GD cases may further develop in to autoimmune thyroiditis later.