The Expression Of IgG4in Thyroid Tissues Of Hashimoto’s Thyroiditis And Analysis Of Their Clinical And Histopathological Characters

Objective To investigate the clinical and histological features of IgG4HT by using theimmunohistochemical staining of IgG4for HT and some other thyroid diseases, so that toprovide a basis for diagnosis, differential diagnosis and treatment.Methods Immunohistochemistry was carried out for assessment of the expression ofIgG4and IgG in29HT patients. Based on the criteria of IgG4-RD, these patients weredivided into IgG4group and non-IgG4group. Statistical analyses of clinical andhistopathological characters were also conducted in both groups. In addition,6patientswith subacute thyroiditis,10with thyroid carcinoma and10with thyroid adenoma werealso examined.Results In all29HT cases,10of them (34.48%) were diagnosed as IgG4HT, while2subacute thyroiditis cases were IgG4positive in26control cases (7.69%), so the HTgroup has a higher positive rate of IgG4staining(P<0.05). The IgG4positive plasma cells,IgG positive plasma cells and ratio of IgG4+/IgG+plasma cells in IgG4HT cases weresignificantly higher than non-IgG4HT ones(P<0.05). IgG4HT was more associated withunilateral thyroid lesion and solitary nodule in the thyroid (P<0.05). The serum FT4inIgG4HT cases were lower than non-IgG4HT ones (P<0.05). After operation, IgG4HThad a greater proportion for accepting thyroxine treatment (P<0.05). The two groupsshowed no significant difference in the degree of stromal fibrosis, lymphoid follicleformation and FT3, TSH, TgAb, TPOAb other clinical features. But the group of IgG4HT seems to have a tendency of hypothyroidism and high content of thyroid antibodies.Comparing with subacute thyroiditis group, the HT group had a lower degree of fibrosis(P<0.05), other pathological features showed no significant difference. The IgG4stainingwas negative in carcinoma and adenoma cases.Conclusion IgG4HT is not uncommon in HT cases. This type of HT has particularhistopathological features and may have some clinical characters, especially the goodresponse for cortical hormone therapy. Serum and tissue examines of IgG4may beconductive to the diagnosis of IgG4HT. Meanwhile, part of subacute thyroiditis maybelong to IgG4related thyroid diseases, more attention should be paid to identification.