OP0320 CHARACTERISTICS OF PERIPHERAL BLOOD B-CELL SUBSETS IN PATIENTS WITH SJOGREN SYNDROME
Authors: A. Torgashina, E. Sokol, J. Khvan, B. Chalcev, D. Tabakov, S. Glukhova, O. Golovina
Journal: Annals of the Rheumatic Diseases (2021)

Background: B-cells play a pivotal role in primary Sjogren’s syndrome (SS) pathogenesis. Recent studies have shown disturbances in the peripheral B cell populations in primary SS. Objectives: To examine В-cell subsets in peripheral blood of SS patients (pts) and to analyze the association between B-cell subsets and SS activity. Methods: Twenty active SS pts (19F/1M): median age 42 years (range) (32-54); disease duration 3 (2-10) years; ESSDAI score ≥5 in 6 pts, &lt;5 in 14 pts), were included. SS was diagnosed based on the ACR-EULAR 2016 criteria. Twenty healthy donors composed the control group. CD19+B cells, memory B-cells (CD19+CD27+), non-switched memory B-cells (CD19+IgD+CD27+), switched memory B-cells (CD19+IgD-CD27+), naïve (CD19+IgD+CD27-), double negative (CD19+IgD-CD27-), transitional (CD19+IgD+CD10+CD38+) B-cells, plasmablasts (CD19+СD38+++IgD-CD27+), and plasma cells (CD19+СD38+) were analyzed by multicolor flow cytometry using cytometer Navios (Beckman Coulter, USA). The nonparametric Mann-Whitney test, the unpaired Student’s t test for group comparison, and the Pearson`s x2 criterion were used for statistical analysis. Data were shown as median (Me) with an interquartile range of 25 - 75 percentile. The differences were considered statistically significant when p &lt;0.05. Statistica 10 for Windows (StatSoft Inc., USA) package was used for statistical data processing. Results: The percentages/absolute numbers of plasmablasts, plasma cells and transitional B-cells in SS were significantly higher than in healthy donors, р&lt;0.01 for all cases (Table 1). Table 1. B-cell subsets in patients with SS, SS and MALT lymphoma and healthy donors. B-cell subsets SS HD Pt 1 FN % Abs. cells/μl % Abs. cells/μl % Abs. cells/μl B lymphocyte 12,8 (7,9 – 19,7) 151 (95-112) 8,5 (7,2-11,0) 200 (100-200) 4,5 31 ** plasma cells 6,9 (4,2-10) 12 (6-22) 0,1 (0,05-0,1) 0,1 (0-0,2) 5,7 13 * plasmablasts 0,88 (0.37-1.8) 2 (1-3) 0,1 (0,1-0,2) 0,2 (0,1-0,4) 26,6 12 */** transitional B-cells 5.7 (0.9-17) 8 (4-32) 0,1 (0-0,1) 0,1 (0-0,3) 0 0 * switched cells 9.1 (5.9-20.7) 18 (11-29) 12,8 (9,3-17,0) 20 (10-40) 52 16 ** non-switched memory B-cells 4.13 (2.7-5.4) 7 (3-15) 7,4 (3,7-11,1) 10 (5-20) 16 5 ** SS Sjogren’s patients; HD healthy donors, Pt 1 patient with SS and MALT lymphoma * SS and HD groups compared, р&lt;0.01 ** Pt 1 and SS group compared One of the patients (Pt 1) was diagnosed with MALT lymphoma of the parotid salivary gland; she had a distinct B-lymphocyte subpopulations distribution, which was different from the rest of the SS group. She had the lowest percentage / absolute B lymphocyte count of all patients with SS, the highest percentage of switched cells and non-switched memory B-cells, and the highest percentages/absolute numbers of plasmablasts. For this reason, the patient was excluded from the subsequent analysis (Table 1). Patients with activity of SS by ESSDAI ≥ 5 had a significantly higher percentage of B cells (p=0.007), and significantly higher absolute B lymphocyte count of naïve cells (p=0.04) and plasmablasts (p=0.048). Conclusion: Immunophenotyping showed disturbed homeostasis of the B-cells subpopulations in our SS cohort. A significant increase in plasmablasts in SS, as well as a positive correlation of the level of plasmablasts with the SS activity and presence of lymphoma could suggest the important role of these cells in the pathogenesis of SS. Disclosure of Interests: None declared.