POS0290 PREDICTING RISK FACTORS OF MALT LYMPHOMA IN SJÖGREN’S SYNDROME
Authors: L. Chatzis, V. Pezoulas, A. Goules, I. Stergiou, C. Mavragani, H. M. Moutsopoulos, M. Voulgarelis, D. Fotiadis, A. Tzioufas
Journal: Annals of the Rheumatic Diseases (2021)

Background: Primary Sjögren Syndrome (SS) is a slowly progressive systemic autoimmune disease complicated by lymphoma, with mucosa associated lymphoid tissue (MALT) type being the most common lymphoma form. Several predictors related to pSS associated lymphomas have been described, but there are no studies focusing on specific risk factors for the MALT histologic subtype. Objectives: To identify predictors at SS diagnosis for MALT lymphoma development in pSS patients using simple clinical features. Methods: From 815 SS patients of a single center fulfilling the 2016 ACR/EULAR criteria, those with subsequent development of MALT lymphoma according to the 2016 WHO classification were identified and matched in 1:2 ratio, with non-lymphoma SS control patients according to age, disease duration from SS diagnosis and gender. Lymphoma patients diagnosed within a year from SS diagnosis were excluded from the current study. Clinical, laboratory, histologic data as well as the ESSDAI scores at the time of SS diagnosis were recorded and compared between lymphoma and non-lymphoma patients. Independent lymphoma predictors were identified by a data driven Fast Correlation Based Feature selection (FCBF)/Logistic Regression (LR) algorithm. Results: A unified dataset of 57 MALT lymphoma patients and 114 non lymphoma controls along with 39 features/variables was generated. The median age of SS diagnosis and the disease duration from SS diagnosis to lymphoma diagnosis (lymphoma group) or last follow up (control group) was 50,5 years old (range 25-77) and 7 years (range 0- 30) for the control group and 50 years old (range 24-70) and 8 years (range 1 -30) for the lymphoma group, respectively. MALT lymphoma patients presented more frequently with palpable purpura (23,2% vs 5,3% p=0,001), cryoglobulinemia (30,2% vs 1,6% p&lt;0,0001), low C4 serum levels (62,9% vs 32,1% p=0,0003), rheumatoid factor (76,9% vs 56,1% p=0,01), anti La/SSB antibodies (33,9% vs 50,8% p=0,049) and higher median ESSDAI score (5 vs 2, p&lt;0,0001). In contrast, autoimmune thyroiditis was more prevalent in controls (48,2% vs 18,6%, p=0,004). The FCBF/LR model revealed cryoglobulinemia (p=0,03) and ESSDAI at SS Diagnosis (p&lt;0,001) as the only independent lymphoma predictors. Conclusion: MALT is the predominant pSS related lymphoproliferative histologic type, associated with systemic disease activity and vasculitic manifestations at SS diagnosis. Cryoglobulinemia and ESSDAI score were proven independent risk factors for MALT lymphoma development. Table 1. An FCBF-based multivariable logistic regression analysis results for investigating risk factors for MALT lymphoma development Prominent feature Regression coefficient Odds ratio p-value CI low CI upper Cryoglobulinemia 1.67 5.342 0.033* 1.18 24.327 Total ESSDAI at diagnosis 0.28 1.318 &lt;0.001* 1.208 1.439 Kidney involvement 0.07 1.069 0.5 0.101 0.351 •&lt; 0.05 (95% confidence interval). The rest of the features that participated in the analysis include the following: Palpable purpura, Low C4, Salivary gland enlargement, Lacrimal gland enlargement, ANA Titers, RF, Focus score at Sjögren diagnosis, PNS involvement, Anti-La, Disease duration from SS onset to SS diagnosis, Neutrophils&lt;1500, Autoimmune thyroiditis, Lung involvement – interstitial disease Type, Lymphocytes&lt;1000, Lymphadenopathy fixed, Arthralgias, Dry eyes, Raynaud, Gender, Age at Sjögren diagnosis, Dry mouth, Aca, Hb&lt;12.5 g/dL, ANA, Disease duration from SS Diagnosis to Lymphoma diagnosis or last follow up, Anti-Ro, Arthritis, WBC&lt;4000/μL, Lung involvement bronchocentric disease, Interstitial renal disease, PLTs&lt;100.000/μL, Liver involvement-PBC, Liver involvement–autoimmune hepatitis, CNS involvement. •AUC=0.78 Disclosure of Interests: None declared