Autoimmune and non-autoimmune thyroid diseases have different patterns of cellular HLA class II expression

• Autor(a) principal: Zantut-Wittmann,Denise Engelbrecht
• Data de Publicação: 1999
• Outros Autores: Boechat,Luís Henrique Barbosa, Pinto,Glauce Aparecida, Trevisan,Miriam Aparecida da Silva, Vassallo,José
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: São Paulo medical journal (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1516-31801999000400004
• topic: Graves’ disease; Autoimmune thyroiditis; HLA-DR antigens; Immunohistochemistry

CONTEXT: Surface HLA-DR antigen is usually only expressed by antigen-presenting cells (APC). In autoimmune thyroid disease, follicle cells function as APC, thus expressing HLA-DR. However, non-autoimmune thyroid diseases may also express surface class II antigens. OBJECTIVE: To evaluate the presence and pattern of HLA class II expression in autoimmune and non-autoimmune thyroid disorders. DESIGN: Retrospective: histopathological and immunohistochemical analysis. LOCATION: Referral center, university hospital. SAMPLE: Ten histologically normal thyroids, 11 Graves’ disease, 7 Hashimoto’s thyroiditis, 10 atoxic multinodular goiter and 3 toxic adenomas were analyzed by immunohistochemistry, using a monoclonal antibody anti-HLA-DR. MAIN MEASUREMENTS: The presence of these antigens in thyroid follicular cells and their relation to inflammatory infiltrate was evaluated. The pattern of HLA-DR expression in thyroid follicular cells was analyzed: membrane, cytoplasmic or both. RESULTS: Although HLA-DR antigens were sparsely present in one of the 8 normal thyroids, in 6 of the 9 atoxic multinodular goiter and in 2 of the 3 toxic adenomas a net positivity could be seen in large areas. In all 5 Hashimoto’s thyroiditis and in 7 of the 10 Graves’ disease cases. This expression occurred in follicle cells either in contact with inflammatory cells or not. In non-autoimmune thyroid disease, HLA-DR positivity was essentially cytoplasmic, whereas in Graves’ disease and Hashimoto thyroiditis it was mainly in cell membranes. CONCLUSIONS: It is suggested that the HLA class II expression on the surface of follicle cells could be related to auto-antigen presentation to the immune system by these cells, leading to inflammation.