Expression of CD226 is upregulated on Tr1 cells from neuromyelitis optica spectrum disorder patients

BACKGROUND: Neuromyelitis optica spectrum disorder (NMOSD) is a central and acute demyelinating disease of the central nervous system with unusual clinical course. The development of novel biomarkers for NMOSD is critical for implementing effective clinical treatment. CD226 is known to be expressed on many types of peripheral lymphoid cells. However, the expression level and function of CD226 on type 1 T regulatory (Tr1) cells during NMOSD is unknown. METHODS: Eighteen patients with NMOSD and 10 healthy volunteers were enrolled in the test group to probe the difference of CD226 expression on Tr1 cells using flow cytometric analysis. RESULTS: The expression of CD226 on Tr1 cells exhibited significantly increased tendency in NMOSD patients. Additionally, methylprednisolone and rituximab treatment decreased the expression of CD226 on Tr1 cells. Furthermore, the expression of CD226 on Tr1 cells was correlated with disease severity. CONCLUSION: This study provides a new basic insight into CD226 expression pattern on Tr1 cells, which have great potential to be biomarkers for monitoring the development and treatment of NMOSD.