OP0291 SEVERITY OF LABIAL MINOR SALIVARY GLAND FOCUS SCORE AND FUTURE LYMPHOMA DEVELOPMENT IN SJÖGREN’S SYNDROME
Authors: A. Goules, L. Chatzis, V. Pezoulas, C. Baldini, F. Skopouli, A. Venetsanopoulou, P. Voulgari, S. De Vita, M. Voulgarelis, H. M. Moutsopoulos, D. Fotiadis, A. Tzioufas
Journal: Annals of the Rheumatic Diseases (2021)

Background: The typical histologic picture of focal sialadenitis in the labial minor salivary gland (LMSG) tissues has been incorporated as a parameter in the majority of Sjögren’s syndrome (SS) classification criteria, with focus score (FS) being the most widely used (1). In previous studies, higher FS has been associated with the presence of autoantibodies and extra-glandular manifestations including lymphoma, implying that FS can predict severe disease (2,3). However, there are no studies exploring the association of FS with lymphoma development along with the time interval from SS diagnosis to lymphoma diagnosis. Objectives: To investigate an association of focus score grading with lymphoma development and time to lymphoma occurrence. Methods: From a total population 1998 consecutive patients fulfilling the 2016 ACR-EULAR criteria for SS who were followed-up in 5 Rheumatology centers from Greece and Italy (Universities of Athens, Pisa, Udine, Harokopio and Ioannina) (UPAHI group), those with positive (LMSG) (FS ≥1) were identified. (1). Patients who had not been subjected to an LMSG biopsy or had a negative biopsy (FS&lt;1) or the biopsy was evaluated using other histologic classifications were excluded from the present study. Lymphoma patients with diagnostic LMSG biopsy performed within a year from lymphoma diagnosis as well as non-lymphoma patients with less than 1 year between SS diagnosis and their last follow up, were also excluded. Cumulative clinical and histologic data attributed to SS as defined by ESSDAI and/or ESSPRI, up to lymphoma diagnosis or last follow up, were recorded. A combined data driven Fast Correlation Based Feature selection (FCBF)/Logistic Regression (LR) model was applied on the unified dataset to identify independent lymphoma associated risk factors. A correlation between FS and time interval until lymphoma diagnosis was performed using the Pearson formula. Results: A unified dataset of 618 SS patients with FS≥1 and at least one year of disease duration from SS diagnosis to lymphoma diagnosis or last follow up, with 30 clinical, laboratory and histologic features, was constructed. The median age at SS diagnosis was 53 (range: 15 – 80) years old, the female to male ratio was 20:1 and the median disease duration was 6 years (range: 1-35). Half (49%) of the study population had focus score between one and two (1≤FS&lt;2), followed by a declining proportion of patients accounted for every subsequent escalating FS group. No statistically significant difference was found regarding disease duration among the various FS escalating groups (p= 0.1603, Kruskal-Wallis test). Fifty eight patients had lymphoma with no statistically significant difference in disease duration compared to non-lymphoma controls. The data driven FCBF/LR algorithm with lymphoma on the whole dataset revealed that cryoglobulinemia (p=0.021), salivary gland enlargement (p=0.008) and FS (p=0,049) are independent lymphoma associated risk factors. A statistically significant negative correlation was found using a Pearson formula (R=-0.32 and p=0.015) regarding the focus score and the time to lymphoma diagnosis. Conclusion: This is the largest study of SS patients’ histologic analysis exploring the association of LMSG FS grading with lymphoma development and the time interval until its diagnosis. Higher FS values correlate with increased lymphoma risk and early lymphoma occurrence. Figure 1. Pearson correlation between FS and time interval until lymphoma diagnosis References: [1]Shiboski et al. Arhtritis Rheumatol. 2017 [2]Carrubi et al. Lupus 2015 [3]Risselada AP et al. Ann Rheum Dis 2014 Disclosure of Interests: None declared