Significance of negative costimulatory molecule programmed death-1/programmed death 1-ligand expressions in peripheral blood of patients with neuromyelitis optica spectrum disorder

Objective To discuss the clinical significance of programmed cell death-1 (PD-1) in neuromyelitis optica spectrum disorder (NMOSD) patients by analyzing PD-1 and programmed death 1-ligand (PD-L1) expressions. Methods Sixteen patients with NMOSD, 16 patients with longitudinally extensive transverse myelitis (LETM), 13 patients with opticneuritis (ON), 20 with other diseases of the central nervous system (OTH) and 16 health controls (CONs) were chosen in our hospital from April 2015 to July 2016; their peripheral blood was separately collected. The PD-1 expression in the CD4+T lymphocytes, and PD-L1 expressions in the CD14+ mononuclear leucocytes and CD19+B lymphocytes of peripheral blood were detected by flow cytometry. ELISA was performed to analyze the levels of soluble PD-1 and soluble PD-L1 in plasma samples. Results The PD-1 level from the peripheral blood of NMOSD patients was significantly higher than that from LETM, ON, and OTH patients and CONs (P<0.05). The PD-L1 level of NMOSD patients was significantly higher than that of the other 4 groups (P<0.05). ELISA indicated that levels of soluble PD-1 and soluble PD-L1 in plasma samples from NMOSD patients were significantly higher than those in LETM, ON, and OTH patients and CONs (P<0.05). Conclusion The PD-1/PD-L1 pathway is an important immune response approach and takes part in the earlier stage of the NMOSD pathological process. Key words: Neuromyelitis optica spectrum disorder; Programmed death-1; Programmed death 1-ligand