Increased circulating follicular regulatory T cells in Hashimoto’s thyroiditis

Abstract

Objective: Follicular T helper (Tfh) cells are involved in the pathogenesis of Hashimoto's thyroiditis (HT), while follicular T regulatory (Tfr) cells inhibit Tfh cells, which mediate B cell responses. However, the role of Tfr cells in HT remains unclear.

Methods: Forty-six healthy controls (HCs) and 84 HT patients were enrolled in the study. The percentage of Treg cells, CXCR5⁻ Treg cells, and Tfr cells; the Tfr/Tfh ratio; and the percentage of ICOS, PD-1, CTLA-4, CXCR3 and CCR6 in Tfr cells were investigated; furthermore, the associations between the percentage of Tfr cells or the Tfr/Tfh ratio and the autoantibody indices were investigated.

Results: Compared with that in the HCs, the percentage of Treg cells in the HT patients was not significantly changed, but the percentage of CXCR5⁻ Tfr cells was decreased. In contrast, both the percentage of Tfr cells and the Tfr/Tfh ratio were significantly increased in the HT patients. Among the Tfr cells, the percentage of Th2-like Tfr cells was increased in the HT patients, while the percentage of Th17-like Tfr cells was decreased. Moreover, the percentages of ICOS and PD-1 on Tfr cells were significantly increased in the HT patients, while the percentage of CTLA-4 on Tfr cells was significantly decreased. However, the percentage of ICOS, PD-1 and CTLA-4 on Treg or CXCR5⁻ Treg cells was not significantly changed. Last, no association was found between either the percentage of Tfr cells or the Tfr/Tfh ratio and the antithyroglobulin and antithyroid peroxidase antibody levels in the HT patients.

Conclusions: In the HT patients, the circulating Tfr cell percentage and Tfr/Tfh ratio were significantly increased, but the humoral immune function of Tfr cells might be impaired.

Keywords:

• Tfr cells
• Tfh cells
• CTLA-4
• Hashimoto's thyroiditis
• autoimmunity

Acknowledgements

The authors would like to thank the encouragement and support of all the members in the Department of Clinical Laboratory, Zhejiang Provincial People's Hospital.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Jinlin Liu was supported by National Natural Science Foundation of China [No: 81871707], Zhejiang Provincial Natural Science Fund [No:LY18H200002]. Yanxia Chen was supported by Zhejiang Provincial Health Bureau [No: 2018KY218]. Zhenyao Xu was supported by National Natural Science Foundation of China [No: 81703118].