Increased circulating Tfh17 and PD-1⁺Tfh cells are associated with autoantibodies in Hashimoto’s thyroiditis

Abstract

Objective: Hashimoto’s thyroiditis (HT) is characterized by autoantibodies targeting the thyroid. Abnormal CD4⁺CXCR5⁺T cell levels were previously shown to be associated with HT. However, Tfh cells consist of heterogeneous subpopulations, and which T follicular helper (Tfh) cell subpopulation participates in the pathogenesis of HT remains poorly understood.

Methods: Thirty healthy controls (HCs) and 52 HT patients were enrolled in the study. The percentages of Tfh, ICOS⁺Tfh, PD1⁺Tfh, Tfh1, Tfh2, Tfh17, effector Tfh, resting Tfh, effector memory Tfh, central memory Tfh, and naïve Tfh cells in the peripheral blood were all determined via flow cytometry, and the associations between the percentages of these cells and thyroid function indices were also investigated.

Results: The percentage of Tfh cells was significantly higher in HT patients than in HCs. Examination of the Tfh cell subsets revealed that the percentages of Tfh1, Tfh2, and resting Tfh cells were significantly decreased, while those of the ICOS⁺Tfh, PD1⁺Tfh, Tfh17, and effector Tfh cells were significantly increased in HT patients. No significant differences in effector memory, central memory or naïve Tfh cell percentages were noted between the HC and HT groups. Furthermore, the percentage of PD1⁺Tfh cells was positively correlated with anti-thyroglobulin antibody levels. Most importantly, only Tfh17 cell percentages were positively correlated with anti-thyroglobulin and anti-thyroid peroxidase antibody levels and were negatively correlated serum free T3 and free T4 levels in HT patients.

Conclusions: Increased circulating Tfh17 cell and PD1⁺Tfh percentages are associated with higher autoantibody levels in HT patients, which imply that Tfh17 or PD1⁺Tfh cells may play a pathogenic role in the development of HT.

Keywords:

• Tfh17 cells
• PD-1 + Tfh cells
• Hashimoto’s thyroiditis
• TG-Ab
• TPO-Ab

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, and the technical support from the Dr. Wanmao Ni from the Key Laboratory of Tumor Molecular Diagnosis and Individualized Medicine of Zhejiang Province.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

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