Predictive Effect Of IgG4 On Hashimoto’s Thyroiditis Complicated With Papillary Thyroid Carcinoma

Backgrounp : The correlation between IgG4-related diseases and tumors has been reported successively.Hashimoto’s thyroiditis(HT)can be divided into IgG4-positive HT and non-IgG4-positive HT,and is considered as a risk factor for papillary thyroid carcinoma(PCT).Therefore,there may be a potential association between IgG4-positive HT and PCT.Objective : In this study,the pathological characteristics and clinical information of IgG4-positive HT and PCT were compared to explore the relationship between them and the prognosis of PCT with IgG4-positive HT.Methods : A retrospective study was conducted.The thyroid pathological specimens of 90 patients in our hospital were divided into three groups for the study,including 60 HT patients,30 of whom were combined with PCT(HT+PCT group),30 of whom were not combined with PCT(HT alone group),and 30 of whom were not combined with PCT(PCT alone group)as the control group.Clinical parameters and pathological characteristics were compared between the groups.The three groups of samples were stained for IgG4 by immunohistochemical method,and were divided into IgG4-positive group and non-IgG4-positive group according to the diagnostic criteria of IgG4-RD.The clinical parameters and histomathological characteristics between them were compared and analyzed.Results : Ten patients in the HT+PCT group were IgG4 positive(33.3%),while only two patients in the HT alone group were IgG4 positive(6.7%).Only a small number of patients in the PCT alone had IgG4 staining and could not reach the diagnosis of IgG4 positive.There was statistical significance between IgG4-positive HT and PCT(P=0.021).The course of disease in PCT alone group was shorter than that in the other two groups(P=0.013),and the incidence of single nodules was higher(P=0.023).The maximum tumor diameter of HT+PCT group was smaller than that of the PCT group alone,and Ames staging was all low-risk cases.There were4 high-risk cases in the PCT group alone,but there was no statistically significant difference.The probability of lymph node enlargement was the least in HT alone group(P=0.009).The HT+PCT group was divided into IgG4-positive group and non-IgG4-positive group.The number of IgG4+ cells and the ratio of IgG4+ cells to Ig G+ cells in the IgG4-positive HT+PCT group(hereinafter referred to as the IgG4HT+PCT group)were significantly higher than those in the non-IgG4-positive HT+PCT group(P=0.000).The rate of extravemembrane invasion and the degree of lymphocyte infiltration of the former were significantly higher than that of the latter(P = 0.01 and 0.03,respectively).In addition,the level of TPO-Ab in the IgG4HT+PCT group was slightly lower than that in the non-IgG4 HT +PCT group,while the level of TG-Ab was slightly higher than that in the non-IgG4 HT +PCT group,without statistical significance.However,there were no significant differences in stromal fibrosis degree,Ig G+ plasma cell number,lymph node metastasis,tumor maximum diameter,tumor TNM stage,Ames stage,thyroid function,thyroid ultrasound and other clinical information between the two groups.Conclusion:(1)Autoinflammation of IgG4-positive HT may lead to an increased risk of PCT;(2)Tg Ab and its IgG4 levels may be associated with increased risk in patients with PCT;(3)The clinical prognosis of IgG4-positive HT combined with PCT may be poor.