FRI0242 SUBPOPULATION COMPOSITION OF INFLAMMATORY INFILTRATES OF THE MINOR SALIVARY GLAND AS AN ADDITIONAL DIAGNOSTIC CRITERION FOR PRIMARY SJOGREN’S SYNDROME

Abstract

Background: Primary Sjogren’s syndrome (pSS) is frequent nosological forms among the diffuse connective tissue diseases. Histological examination of the minor salivary gland (MSG) is important diagnostic method. The currently established histological criteria for pSS indicates 61.2-93.7% sensitivity and 61.2-100% specificity respectively, which makes the search for additional hallmark highly relevant. Immunohistochemical study of MSG is the most appropriate for this purpose. Objectives: To study of the qualitative and quantitative compositions of cellular subpopulations minor salivary gland mononuclear foci as additional histological criteria of pSS. Methods: The study included 56 patients with a definite diagnosis of pSS according to the criteria of ACR\EULAR 2016. The control group consisted of 19 healthy volunteers. The biopsy of the minor salivary gland was performed for all the subjects, followed by an immunohistochemical study to evaluate the expression of CD3, CD4, CD8, CD20, CD21, CD68, CD138. A statistical analysis of the data obtained during the study was carried out using the SPSS 23 statistical software for Windows (IBM, United States of America). Diagnostic threshold for each biomarker was determined by ROC analysis. Operating characteristic curve, area under the curve (AUC), specificity, sensitivity, diagnostic accuracy (DT), diagnostic thresholds (DP), positive likelihood ratio (LR+) and negative likelihood ratio (LR-) were also calculated. The construction of classification models, including several markers, was performed using linear discriminant analysis. Results: The largest AUC were observed in CD3 - 0.795 [95% confidence interval (CI) 0.697 - 0.893] and CD20 - 0.796 (95% CI 0.698 - 0.894), which at the specified DP corresponded to the sensitivity of 67.9% (95% CI 54.04 - 79.71) and 71.4% (95% CI 57.79 - 82.7), specificity of 95% (95% CI 73.97 - 99.87) and 95% (95% CI 73.97 - 99.87). The CD21 marker was detected only in the PSS group. AUC for this biomarker was 0.652 (95% CI 0.525 - 0.778), sensitivity - 30.4% (95% CI 18,78 - 44.1), specificity - 100% (95% CI 82,35 - 100). Using the method of discriminative analysis, we designed classification models that included various combinations of the markers under study. The combination of the decimal logarithms CD3 and CD68 had AUC 0.873 (95% CI 0.794 - 0.953), sensitivity - 76.8% (95% CI 63.58 - 87.02), specificity - 95% (95% CI 73.97 – 99.87). Conclusion: CD3 and CD20 can be considered as additional histological criteria for pSS. CD21 was observed only in patients with pSS. The combined quantitative assessment of CD3 and CD68 had a greater diagnostic value compared to CD3 and CD68 separately. Disclosure of Interests: None declared