OP0320 CHARACTERISTICS OF PERIPHERAL BLOOD B-CELL SUBSETS IN PATIENTS WITH SJOGREN SYNDROME

Abstract

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, <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 <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<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 subsetsSSHDPt 1FN%Abs. cells/μl%Abs. cells/μl%Abs. cells/μlB lymphocyte12,8 (7,9 – 19,7)151 (95-112)8,5 (7,2-11,0)200 (100-200)4,531**plasma cells6,9 (4,2-10)12 (6-22)0,1 (0,05-0,1)0,1 (0-0,2)5,713*plasmablasts0,88 (0.37-1.8)2 (1-3)0,1 (0,1-0,2)0,2 (0,1-0,4)26,612*/**transitional B-cells5.7 (0.9-17)8 (4-32)0,1 (0-0,1)0,1 (0-0,3)00*switched cells9.1 (5.9-20.7)18 (11-29)12,8 (9,3-17,0)20 (10-40)5216**non-switched memory B-cells4.13 (2.7-5.4)7 (3-15)7,4 (3,7-11,1)10 (5-20)165**SS Sjogren’s patients; HD healthy donors, Pt 1 patient with SS and MALT lymphoma* SS and HD groups compared, р<0.01** Pt 1 and SS group comparedOne 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.