Studies On The Relationships Between IgG4 Related Diseases And Hashimoto's Thyroiditis And Riedle Thyroiditis

BackgroundIgG4 related diseases(IgG4-RD)is a recently recognized syndrome which is also an immune-mediated disease.it can involve with multiple organs or tissues.In comparation with the orther organs,there are fewer studies about IgG4 related disease of the thyroid.On the other hand,we still don't know too much about that.The pathological histology of Hashimoto thyroiditis(HT)and Riedle thyroidities(RT)are similar to IgG4-RD.So the relationships between IgG4-RD and those two kinds of disease and whether both HT and RT belong to the category of IgG4-RD need to further clarification.This study retrospectively observed the clinical and pathological datas of HT and RT,by comparing and discussing the differences and relationships between them and IgG4-RD respectively and preliminarily.Materials and methodsThe study was divided into two parts:In the first part,five cases of Riedle thyroiditis confirmed in our hospital during April 2012 to August 2015 were collected.HE staining,CD3 8,CD 138,IgG,IgG4 immunohistochemistry staining,Masson and Elastic fiber staining were carried out on these tissue paraffin blocks.Observe the histopathological features and clinical features of these five cases according to the numbers of IgG4 positive plasma cells.In the second part,collect data of 57 cases diagnosed as Hashimoto thyroiditis in our hospital from 2014 to 2016.HE staining,CD38,CD 13 8,IgG,IgG4 immunohistochemistry staining,Masson and Elastic fiber staining were carried out on these tissue paraffin blocks.The 57 cases were divided into IgG4 subtype group and non-IgG4 subtype group.In terms of histopathological features and clinical features,to see wether the differences between these two groups were statistically significant by comparing these two groups.ResultsIn the first part:There were one male and four female patients,aged 52 to 78 years(median 59 years).5 cases were characterized by multiple nodules of thyroid,which increased year by year.All patients were found to have surrounding tissue compression symptoms and signs.2 female patients were found to have hypothyroidism.The serum concentration of IgG was elevated in 2 cases,and the serum concentration of IgG was not tested before operation in the remaining patients.By ultrasound,all presented as Low echo or medium low echo.Strong echo occasionally appeared in hypoechoic nodules.Microscopically,fibrous tissue hyperplasia were infiltrated with varying amounts of lymphocytes and plasma cells.The occlusion of phebitis were found in 4 cases and eosinophils were found in 3 cases.IgG4 counts and IgG4/IgG ratios in 5 cases respectively were:20/HPF,16%;60/HPF;82%;22/HPF,28%;400/HPF,266%;33/HPF,71%.There were 3 cases were diagnosed with IgG4-RD finally.The second part:There were 57 patients,2 males and 55 females,aged 14 to 73 years,with an average age of 43.And there were 18 IgG4 subtypes and 39 non-IgG4 subtypes.The differences of the degree of fibrosis and the formation of lymph follicles under the microscope between these two groups were statistically significant as well as the level of serum A-Tg between the two groups.There were no statistically significant differences between the two groups in the other medical indexes which included age,gender,hypothyroidism,fibrosis and so on.Conclusions(1)With the similar pathological manifestation results betwwen RT and IgG4-RD,immunohistochemical staining showed that the number of IgG4 positive plasma cells and IgG4/IgG ratio of RT were Increased in varying degrees.Some cases meet with the diagnostic criteria of IgG4-RD,and speculate that some cases of RT belong to IgG4-RD.(2)None of the 57 cases of hashimoto's thyroiditis were associated with IgG4 related disease in the other organs.(3)The IgG4 subtype of HT showed the typical features of the IgG4 related disease which mainly including:the diffuse infiltration of lymphoplasmatic cells,different types of interstitial fibrosis,and as well as a large number of IgG4 positive plasma cells infiltrated.(4)Histopathologically,IgG4 subtype of HT showed higher grade of stromal fibrosis,lymphoplasmacytic infiltration,and lymphoid follicles formation.There were statistical differences between these two groups.(5)Compared with IgG4 subtype,the non-IgG4 subtype of hashimoto's thyroiditis came up with a lower level of blood A-Tg.And there was a statistical difference between the two groups.(6)Hashimoto's thyroiditis IgG4 subtype is not completely equal to hashimoto's thyroiditis fibrosis subtypes.They were only partially overlapped.(7)There was no statistical difference between the two groups of hashimoto thyroiditis in the type of fibrosis(interlobular fibrosis and follicular fibrosis).