POS0790 RELATIONSHIPS BETWEEN SALIVA IMMUNOGLOBULINS FREE LIGHT CHAINS CONCENTRATION AND CLINICAL, IMMUNOLOGICAL, HISTOLOGICAL PARAMETERS IN PATIENT WITH PRIMARY SJOGREN’S SYNDROME

Abstract

Background:Patients with primary Sjogren’s syndrome (pSS) exhibit biological signs of B cell activation such as serum polyclonal hypergammaglobulinaemia, increased levels of free light chains (FLC) and positivity for autoantibodies. B-cells may comprise up to 50% cells of lymphocytic infiltrates in salivary glands of patents with the disease. For that reasons measuring saliva B-cells products might have diagnostic value in pSS.Objectives:To evaluate relationships between saliva free light chains concentration and clinical, immunological, histological parameters in patient with pSS.Methods:Saliva and blood FLC concentrations were measured in patient with pSS (n = 24) and healthy volunteers (n = 11). Patients fulfilled the ACR/EULAR 2016 criteria of pSS. Saliva collected during assessment unstimulated salivary flow was used for analysis. Quantitative assessment of CD3+, CD4+, CD8+, CD20+, CD21+, CD68+, CD138+ cells was performed in minor salivary glands of 9 patient by immunohistochemistry. Cells quantity was calculated in 4 mm2 (area of section).Results:FLC concentration in saliva of pSS patients was higher than in healthy volunteers (p<0,01). Medians of saliva κ - and λ – free light chains concentrations in patients and healthy persons were 1,08 mg/L [25-;75- percentiles 0,58;1,91], 1,038 mg/L [0,55;2,03] and 0,36 mg/L [0,32; 0,54], 0,35 mg/L [0,21; 0,52] respectively. Median of saliva κ: λ chains ratio in pSS patient was 0,94 [0,6;1,5]. The ratio didn’t differ from healthy persons (p=0,24). Saliva κ – and λ – free light chain concentrations in patient with pSS correlated with patients age (rs= 0,51, p=0,033 and rs=0,43, p= 0,011, respectively) and unstimulated salivary flow (rs= -0,48, p=0,02 and rs=-0,49, p= 0,017, respectively). Concentration of κ – free light chain correlated with number of CD138+-cells (rs= 0,733, p=0,025). Interesting that saliva λ – free light chain concentration didn’t correlate with quantity of plasmatic cells.Conclusion:Measuring saliva FLC concentration might be offered as diagnostic marker of pSS. Concentration κ – free light chain can directly mirror the glands quantity of plasmatic cells.