Spatial correlation between thyroid epithelial cells expressing class II MHC molecules and interferon‐gamma‐containing lymphocytes in human thyroid autoimmune disease

Abstract

In this immunohistochemical study we addressed the question whether aberrant class II MHC expression by thyroid epithelial cells (thyrocytes) in established thyroid autoimmune disease is the result of release of interferon‐gamma(IFN‐γ) by adjacent lymphocytes. Thyroids from eight cases of Hashimoto's thyroiditis, 13 cases of Graves' disease and 10 cases of focal thyroiditis were studied. Both thyrocytes expressing class II MHC and lymphocytes containing immunoreactivc IFN‐γ were found in all 31 autoimmune thyroids. In a serial section study of these thyroids. IFN‐γ‐exprcssing lymphocytes were found within 50 μ of class II MHC‐positive thyrocytes in 89% of 282 randomly selected fields. Conversely, class II MHC‐positive thyrocyles were found wilhin 50 μ of aggregates of IFN‐γ‐positive lymphocytes in 82% of 272 randomly selected fields. These findings support the view that in established thyroid autoimmune disease expression of class II MHC by thyrocytcs is the result of local release of IFN‐γ. Copyright © 1991, Wiley Blackwell. All rights reserved