Identification of novel HLA-A0201-restricted T-cell epitopes against thyroid antigens in autoimmune thyroid diseases

Expression of integrin α4β1 and α4β7 on B cells correlates with autoimmune responses in Graves' disease

BACKGROUND

Integrins are upregulated on endothelial cells and T-lymphocytes in autoimmune thyroid disease (AITD), potentially contributing to immune response localization. The role of integrins on B-cells in AITD remains unclear.

METHODS

Peripheral blood samples were collected from healthy controls (n = 56), patients with Graves' disease (GD) (n = 37) and Hashimoto's thyroiditis (HT) (n = 52). Ultrasound-guided fine-needle aspiration (FNA) of the thyroid was performed in patients with non-autoimmune thyroid disease (nAITD) (n = 19), GD (n = 11), and HT (n = 40). Integrins α4β7, α4β1, and αEβ7 in B cells were measured by flow cytometry. Serum zonulin levels were quantified via ELISA. Associations of integrins on B cells with thyroid hormones, thyroid autoantibodies, AITD duration, and zonulin were analyzed.

RESULTS

HT patients exhibited lower α4β7 and higher α4β1 expression on B cells compared to healthy controls and GD patients. While α4β7 was predominant on circulating B cells, the dominant integrin expressed on intrathyroidal B cells varied with specific thyroid diseases. In GD patients, α4β7 and α4β1 expression on circulating B cells correlated positively and negatively with thyroid function and thyroid stimulating immunoglobulins (TSI) levels, respectively. Intrathyroidal α4β1+ B cells positively correlated with TSH levels in HT patients. Additionally, serum zonulin was elevated in HT patients, and intrathyroidal α4β7+ B cells and α4β1+ B cells correlated negatively and positively with zonulin levels, respectively. Integrin αEβ7 on B cells showed no significant association with AITD.

CONCLUSION

Integrins expressed on B cells potentially play a role in the pathogenesis of AITD and might serve as immune biomarkers for the disease.

The Frequency of Intrathyroidal Follicular Helper T Cells Varies with the Progression of Graves’ Disease and Hashimoto’s Thyroiditis

Objective

Autoimmune thyroid diseases (AITD), mainly Graves' disease (GD) and Hashimoto's thyroiditis (HT), are common organ-specific autoimmune diseases characterized by circulating antibodies and lymphocyte infiltration. Follicular helper T (Tfh) cell dysregulation is involved in the development of autoimmune pathologies. We aimed to explore the role of intrathyroidal and circulating Tfh cells in patients with GD and HT.

Methods

Ultrasound-guided thyroid fine-needle aspiration (FNA) was conducted in 35 patients with GD, 40 patients with HT, and 22 patients with nonautoimmune thyroid disease (nAITD). Peripheral blood samples were also obtained from 40 patients with GD, 40 patients with HT, and 40 healthy controls. The frequencies of intrathyroidal and circulating Tfh cells from FNA and peripheral blood samples were assessed by flow cytometry. Additionally, the correlations between the frequencies of the Tfh cells and the levels of autoantibodies and hormones or disease duration were analyzed.

Results

The frequency of intrathyroidal CD4⁺CXCR5⁺ICOS^high Tfh cells was higher in HT patients than in GD patients. Significant correlations were identified between the percentages of circulating and intrathyroidal Tfh cells and the serum concentrations of thyroid autoantibodies, especially thyroglobulin antibodies (TgAb), in AITD. Intrathyroidal CD4⁺CXCR5⁺ICOS^high Tfh cells were positively correlated with free triiodothyronine (FT3) in HT patients but negatively correlated with FT3 in GD patients. In addition, HT patients with a longer disease duration had an increased frequency of intrathyroidal CD4⁺CXCR5⁺ICOS^high and CD4⁺CXCR5⁺PD-1⁺ Tfh cells. In contrast, in the GD patients, a longer disease duration did not affect the frequency of intrathyroidal CD4⁺CXCR5⁺ICOS^high but was associated with a lower frequency of CD4⁺CXCR5⁺PD-1⁺ Tfh cells.

Conclusions

Our data suggest that intrathyroidal Tfh cells might play a role in the pathogenesis of AITD and they are potential immunobiomarkers for AITD.