Profiles of peripheral B cell subsets in a cohort of primary Sjögren's syndrome patients and their potential clinical significance

Primary Sjögren's syndrome is a prototypical autoimmune disease, with B cell dysfunction as a dominant feature. Further insights into distribution of B cell subsets in primary Sjögren's syndrome are urgently required to identify the most appropriate target subpopulation. We aimed to evaluate the profiles of B lymphocyte subpopulations in primary Sjögren's syndrome patients and to investigate their clinical significance. Thirty primary Sjögren's syndrome patients and 15 age-and sex-matched healthy controls were recruited. Peripheral B cell subsets were analyzed by flow cytometry. Compared to healthy controls, circulating CD19+ B cells, CD19+CD20− B cells, CD19+CD27−IgD+ naïve B cells, CD19+IgD+CD38high plasmablasts, CD19+CD24highCD38high transitional B cells and CD19+CD20−CD27+CD38+ plasma cells were elevated in patients with primary Sjögren's syndrome, whereas CD19+CD27+ memory B cells, CD19+CD27−IgD- double negative B cells and CD19+CD24hiCD27+ Bregs were decreased. Furthermore, the percentage of circulating CD19+CD20−CD27+CD38+ plasma cells was positively correlated with serum IgG levels and the proportional area of lymphocytic infiltration of labial gland. We identified a comprehensive B lymphocyte subset distribution profile in primary Sjögren's syndrome. Moreover, we detected a clinical significance of CD19+CD20−CD27+CD38+ plasma cells, suggesting that these cells might play a key role in disease pathology and represent potential therapeutic targets.