The Expression Of IgG Subclasses In Thyroid Tissues Of Hashimoto’s Thyroiditis And Analysis Of Their Clinical And Histopathological Characters

【Objective】 To investigate Ig G subclasses distribution of HT by using the immunohistochemical staining of Ig G subclasses for pathological tissue of HT, so that to provide a basis for diagnosis, prognosis and sequential treatment.【 Methods 】 Immunohistochemistry was carried out for assessment of the expression of Ig G subclasses in 29 HT patients. Based on the immunohistochemical results, these patients were divided into Ig G1/2/3/4 HT group and non-Ig G1/2/3/4 group,respectively. Statistical analyses of clinical and histopathological characters were conducted in these groups, and flow cytometry was used to measure total plasmablast.【Results】 In all 28 HT cases, 23 of them(82.1%) were marked as Ig G1 HT, 6 of them( 21.4%) were marked as Ig G2 HT, 7 of them(25.0%) were marked as Ig G3 HT, 11 of them were marked as Ig G4 HT. As well as Ig G2 HT group and non-Ig G2 HT group, all the parameters showed no statistical difference between Ig G3 HT group and non-Ig G3 group. The globulin level in Ig G1 HT group were significantly higher than non-Ig G1 HT group(P=0.014),but all the other parameters showed no statistical difference between the two groups(P >0.05). The levels of TSH in Ig G4 HT group were higher than those in non-Ig G4 HT, but there was no statistically difference(P=0.051), the serum FT4 and TPOAb showed statistical differences between the two groups(P=0.041 and P=0.008, respectively), and the Ig G4 HT group had a tendency of hypothyroidism with significant difference(P=0.038). After operation, Ig G4 HT group had a greater proportion for accepting thyroxine treatment(P=0.022). Furthermore,there were more trace-compression cases in Ig G4 HTgroup(P=0.020), the sonographic examinations revealed that the Ig G4 HT group was significantly correlated with low echogenicity, whereas the non-Ig G4 HT group showed an association with mixed echogenicity(P= 0.042). Flow cytometry was used to measure total plasmablast counts by gating peripheral blood of 4 volunteers, 2 of them were Ig G4 HT, whose total plasmablast counts were 8960/ml and 8029/ml, meanwhile, the other two were non-Ig G4 HT, whose counts were 4601/ml and 5353/ml.【Conclusion】 Although positive rate of Ig G1 in pathology organization of HT was the highest, it was not correlated to the clinical features and prognosis of HT, as well as the rate of Ig G2 and Ig G3, meanwhile, positive rate of Ig G4 showed a significant predictive effect for the prognosis of HT. Ig G4 HT group had a tendency of poor prognosis, such as hypothyroidism, trace-compression, and Ig G4 HT was more likely to accept thyroxine treatment after operation, but the compound type of Ig G subclasses appear to perform a more important predictive role. This study of 4 patients’ data indicated that circulating plasmablasts counts may be correlated to positive rate of Ig G4 staining.