Expression of TLR10 in Peripheral B Cell Subsets of Patients with Primary Sjögren’s Syndrome

Primary Sjögren’s syndrome (pSS) is considered as a B cell-mediated disease, yet the precise role of B cells in the pathogenesis is not fully understood. Toll-like receptor 10 (TLR10) is highly expressed in human B cells, indicating that TLR10 probably plays a vital role in regulating B cell function as well as B cell-related diseases. However, the biology of TLR10 in pSS is less researched. Here, we examined the TLR10 expression in peripheral B cell subsets isolated from both pSS patients and healthy controls (HCs) and further analyzed the correlations between TLR10 expression and disease activity. We observed that TLR10 was highly expressed in switched memory B cells (CD19+CD27+IgD−) in the pSS patients compared with the HCs. TLR10 expression in CD19+ B cells, memory B cells (CD19+CD27+) and switched memory B cells in pSS patients was negatively correlated with serum levels of anti-SSA antibody and B cell-activating factor of TNF family (BAFF), respectively. A much lower proportion of high-activity pSS patients was observed in TLR10 high- as compared to low-expressed patients. TLR10 expression in CD19+ B cells, naïve B cells (CD19+CD27−IgD+), memory B cells, and switched memory B cells was significantly increased in low-activity pSS patients as compared with HCs and high-activity pSS patients. Our study concluded that TLR10 expression in CD19+ B, naive B, and memory B cells was negatively correlated with pSS disease activity, suggesting that TLR10 might play a critical in the progression of pSS.