Expansion of inflammatory monocytes in periphery and infiltrated into thyroid tissue in Graves\u2019 disease

Xinxin Chen,Mengxi Zhou,Yanqiu Wang,Weiqing Wang,Shu Wang,Yicheng Qi,Fengjiao Huang,Guang Ning,Jiqi Yan,Yulin Zhou

doi:10.1038/s41598-021-92737-4

Xinxin Chen, Mengxi Zhou + Show 8 more

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https://doi.org/10.1038/s41598-021-92737-4

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Abstract

Monocytes are important mediators of immune system and are reported to be altered in autoimmune disorders. Little is known about the pathological role of monocytes in Graves’ disease (GD). Thus, we investigated monocytes in periphery and thyroid tissue in GD. Untreated GD patients were enrolled and followed up until remission. Monocytes were significantly increased and positively correlated with anti-thyrotropin receptor antibody (TRAb) in untreated GD (rcounts = 0.269, P < 0.001; rpercentage = 0.338, P < 0.001). Flow cytometry showed CD14++ CD16+ monocytes were increased and CD14++ CD16- monocytes were decreased in untreated GD (both P < 0.001). Skewed monocyte subsets were recovered in GD with remission. Serum B cell-activating factor (BAFF) was positively correlated with TRAb (r = 0.384 and P = 0.001). CD14++ CD16+ monocytes expressed higher level of BAFF in untreated GD (P < 0.05). The frequency of CD14+ monocytes and CD14+ CD16+ monocytes were significantly higher in GD thyroid tissue than in normal thyroid tissue (both P < 0.001). Our study suggested CD14++ CD16+ monocytes were significantly expanded and involved in the production of TRAb via secreting a higher level of BAFF in periphery. Besides, monocytes infiltrated into thyroid tissue and thus could serve as an important participant in GD pathogenesis.

Highlights

Monocytes are important mediators of immune system and are reported to be altered in autoimmune disorders
A total of 72.3% uGD patients were females (n = 60), and 27.7% of the uGD patients were males (n = 23). uGD patients had increased FT3 and FT4 levels and a decreased thyroidstimulating hormone (TSH) level in the serum, whereas thyroid function returned to normal in eGD patients and normal thyroid function and TRAbnegative GD (nGD) patients were negative for thyrotropin receptor antibody (TRAb) after antithyroid drug treatment (Table 1)
The percentages and absolute counts of monocytes gradually decreased in patients with eGD or nGD and were not significantly different from those in healthy controls (HCs)

Summary

Introduction

Monocytes are important mediators of immune system and are reported to be altered in autoimmune disorders. Monocytes were significantly increased and positively correlated with anti-thyrotropin receptor antibody (TRAb) in untreated GD (rcounts = 0.269, P < 0.001; rpercentage = 0.338, P < 0.001). Our study suggested CD14++ CD16+ monocytes were significantly expanded and involved in the production of TRAb via secreting a higher level of BAFF in periphery. Monocytes circulate in the blood and increase and infiltrate into tissue during inflammation. CD14++ CD16- monocytes account for the majority of circulating monocytes in the steady state, and they are not the predominant cytokine-producing monocytes in humans The latter two monocyte subsets (CD14++ CD16+ and CD14+ CD16 +) are known as inflammatory monocytes. The infiltration of monocytes into locally inflamed tissue may play important roles in maintaining and amplifying the immune response. Little is known about the presence of monocytes in the local thyroid tissue in GD patients

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