The Significance Of Serum IgG4 And IgG4/IgG Ratio In The Differential Diagnosis Of IgG4-related Primary And Sjogren's Syndrome

Objective: The role of IgG4 and IgG4/IgG ratio in the differential diagnosis of Igg4-related disease(Igg4-rd)and primary Sjogren's syndrome(pSS);Methods: Choose between January 2012 and December 2018,rheumatology shengjing hospital affiliated hospital of China medical university make a diagnosis and give treatment for 42 cases of IgG4 correlation disease,choose the same diagnosis of primary sjogren's syndrome in patients with elevated serum IgG4 16 people as control group,two groups of patients serum IgG4,IgG inspection,quantitative data using the median(interquartile range),said the comparison between the two groups the Mann-Whitney U test.Taking primary sjogren's syndrome as the control group,receiver operating characteristic curve(ROC)was plotted with serum IgG4 and IgG4/IgG ratios,respectively,to determine the optimal threshold and AUC under the curve.Results: 1.The median of serum IgG4 and serum IgG4/IgC in 42 patients with igg4-related diseases was 8.61g/L and 0.51,both significantly higher than that in the pSS group(2.49g/L and 0.13,respectively),with statistically significant differences(Z values were-3.906 and-4.663,respectively,P<0.05),while the median serum IgG of patients in the pSS group was 21.25g/L,higher than 17.30g/L in the Igg-rd group,and the difference was statistically significant(z-value was-2.175,P=0.03).2.The ROC curve was drawn for the primary SS group with IgG4 elevation as the control group.The optimal critical value of serum IgG4 was 2.79g/L,the sensitivity was 92.9%,the specificity was 75%,and the area under the curve was 0.834p<0.05.When the IgG4/IgG threshold value was 0.2,the Youden index was the largest,the sensitivity was 90.5%,the specificity was 87.5%,and the AUC was 0.899p<0.05.The optimal critical value of serum IgG was 9.0g/L,with a sensitivity of100% and a specificity of 0.2.The optimal critical value of serum IgG was 70.6g/L,with a specificity of 100%,a sensitivity of 0,and an AUC of 0.314 P=0.03.The difference was statistically significant.3.Conclusion: This study found that serum IgG4 and IgG4/IgG ratio can be used as diagnostic indicators for Igg4-Rd,with high specificity.By drawing ROC curve,it is recommended that serum IgG4 and IgG4/IgG boundary values are 2.79g/L and 0.2,which are of great significance for the differential diagnosis of Igg4-related diseases and primary sclerosing syndromes with elevated serum IgG4.