To investigate the expressions of costimulatory molecules OX40 and OX40L on peripheral blood mononuclear cells (PBMC) and their relationship with clinical characteristics of patients with primary Sjogren's syndrome (pSS).
Peripheral blood samples were collected from 51 pSS patients and 36 healthy subjects (HC). The expressions of OX40 and OX40L on PBMC were detected by immunofluorescence and flow cytometry. In addition, we observed the changes in the levels of OX40 and OX40L after treatment in 11 patients with primary pSS and searched for the relationship between their expression levels and patients' clinical manifestations.
The expression of OX40 on CD4(+);T cells in pSS patients was significantly higher than that in the HC group (8.65%±3.51% vs 5.68%±1.68%, P<0.01). However, there was no significant difference in OX40 expression on CD8(+);T cells between patient group and HC group. In comparison with HC group, the expression of OX40L on CD14(+); monocytes (6.76%±3.60% vs 3.15%±1.89%, P<0.01) and CD19(+);B cells (4.69%±2.40% vs 2.76%±1.33%, P<0.01) significantly increased in pSS patients. Moreover, OX40 expression on CD4(+);T cells and OX40L expression on monocytes and B cells rose significantly in active pSS patients compared with those in inactive patients. The expression levels of OX40 and OX40L were higher in pSS patients with multiple system damage than in patients with simple exocrine gland injury. In addition, immunosuppressive therapy significantly reduced the expressions of OX40 and OX40L.
The expressions of OX40 and OX40L on peripheral lymphocytes was upregulated in pSS patients. The high levels of OX40 and OX40L expression were significantly correlated with clinical outcome and therapeutic response, suggesting that OX40/OX40L pathway may play a critical role in pSS pathogenesis.