The Characteristic Of Lymphocyte Subset Distribution In Thyroid Tissue From Patients With Hashimoto’s Thyroiditis And Graves’ Disease

BackgroundHashimoto’s thyroiditis (HT) and Graves’ disease (GD) are the two most important clinical presentations of Autoimmune thyroid diseases (AITD). AITD is characterized by lymphocytic infiltration of the thyroid parenchyma, with an immune attack on the thyroid gland and the production of thyroid autoantibodies. In Hashimoto’s thyroiditis, the production of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) can be found. In Graves’disease, the infiltration is mild and induces the production of TSH receptor antibody (TRAb). There are many studies on the distribution of peripheral lymphocyte subsets in HT and GD, but study on the distribution of lymphocyte subsets in thyroid tissue is rare. Our study discuss the difference of the distribution of lymphocyte subsets in thyroid tissue between HT and GD, and the relationship between the distribution and the level of TPOAb, TgAb, and TRAb. It may help to reveal the pathogenesis of AITD.ObjectiveTo observe the distribution and characteristic of lymphocyte subsets in thyroid tissue from patients with HT or GD, and the relationship between thyroid autoantibodies levels and extent of thyroid lymphocyte infiltration.Subjects and Methods1SubjectsThe total of98patients with HT, GD and with non-functioning thyroid nodules.2Diagnostic criteriaThe diagnosis of HT is according to the diagnostic criteria, which is made by China thyroid disease treatment guidelines in2008. The diagnosis of GD is according to the diagnostic criteria, which is made by China thyroid disease treatment guidelines in2007. The diagnosis of non-functioning thyroid nodules:diagnosed by ultrasound, and with nomal euthyroid, TPOAb, TgAb and TRAb. 3GroupingPatients were divided into3groups. There were46patients in HT group (male:7, female:39), the the average age was35.1±14.5years old. There were27patients in GD group (male:6, females:21), the the average age was36.8±12.3years old. Take patients with non-functioning thyroid nodules as control group, the total was25(male:6, female:19), the average age was38.7±13.5years old.4Methods4.1Specimen collectionThyroid tissue was obtained through ultrasound-guided fine needle aspiration.4.2Cytological examinationPart of the obtained tissue was made into smear for cytologic examination.4.3Determine the ratio of lymphocyte subsetsThe rest part of the thyroid tissue was experimented by technique of flow cytometry to measure the ratio of CD3+T lymphocytes, subpopulations of CD3+CD4+and CD3+CD8+T cells, CD4+CD25+CD127-Treg, CD3-CD19+B cells, CD3(CD16+/CD56+)NK cells and CD4+/CD8+in thyroid tissue.4.4Measured thyroid antibodies:Measured TPOAb, TgAb, TRAb by radioimmunoassay and chemiluminescence respectively.Results1. HT group:Compared with control group, the percentage of CD3+T lymphocytes in patients with HT was increased; The percentage of CD4+CD25+127" Treg in patients with HT was decreased(P<0.05); Compared with GD group, the percentage of CD3+T lymphocytes with HT was enhancedtP<.0.05).2. GD group:Compared with control group, the percentage of CD3"(CD16+/CD56+)NK cells and CD4+CD25+127" Treg in patients with GD was decreased; The percentage of CD3+CD4+T cells and CD4+/CD8+in patients with GD was increased (P< 0.05); Campared with HT group, the percentage of CD3+CD4+T cells and CD4+/CD8+in patients with GD was increased; The percentage of CD3-(D16+/CD56+) cells in patients with GD was decreased (P<0.05).3. The percentage of CD3+CD8+T cells and CD3"CD19+B cells did not change dramaticly in HT group and GD group(P>0.05). The percentage of CD4+CD25+127"Treg had no significant difference between the two groups(P>0.05).4. The level of TPOAb and TgAb had positive relevance with the extent of thyroid lymphocyte infiltration in HT group, there was no correlation between TRAb level and the degree of thyroid lymphocyte infiltration.Conclusion1. The percentage of CD3+T lymphocytes was increased, the percentage of CD4+CD25+127-Treg was decreased in thyroid tissue from patients with HT. It is suggested that the disorder of T lymphatic cell proportion and the decrease of negative regulate T lymphocytes lead to the auto-reactive T cell activation.2. The percentage of CD3(CD16+/CD56+) NK cells and CD4+CD25+127" Treg was decreased, the percentage of CD3+CD4+T cells and CD4+/CD8+was increased in thyroid tissue from patients with GD. It is suggested that the proportional imbalance of CD4+/CD8+and the decrease of CD3(CD16+/CD56+) NK inhibited the antibody production, which destroyed the immune stability in vivo, and led to immune regulation disorder.3. Thyroid antibodies level had positive relevance with thyroid lymphocyte extent of infiltration in patients with HT. It is suggested that there is an inherent connection between the two types of immune dysfunction.