Th2 axis-related cytokines in patients with neuromyelitis optica spectrum disorders

AIMS: Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory autoimmune disease of the central nervous system. Increasing evidence indicates that NMOSD is a Th2‐ and Th17‐dominant disease. IL‐25, IL‐31, and IL‐33 are three newly found Th2‐related cytokines, and their roles in the pathogenesis of NMOSD have not been studied. This study aimed to measure the serum levels of IL‐25, IL‐31, and IL‐33 in patients with NMOSD and evaluate their clinical implications. METHODS: Serum was collected from patients with NMOSD (n = 48) and healthy controls (HC, n = 28). Serum level measurements of IL‐25, IL‐31, IL‐33, IL‐17A, and IL‐6 were performed using enzyme‐linked immunoassay (ELISA) method. RESULTS: The serum levels of IL‐25, IL‐31, and IL‐33 were significantly higher in patients with NMOSD as compared to HC. The serum level of IL‐31 was significantly correlated with IL‐17A (r = 0.382,P = 0.009) in patients with NMOSD; the latter is a critical cytokine in the pathogenesis of NMOSD. The serum level of IL‐33 was higher in patients with characteristic brain lesions than patients without (307 pg/mL vs 166 pg/mL, P = 0.028). Furthermore, the serum level of IL‐33 in the acute phase of the disease was positively correlated with annualized relapse rate (r = 0.364, P = 0.04). CONCLUSION: We found higher serum levels of IL‐25, IL‐31, and IL‐33 in patient with NMOSD as compared to healthy controls. The serum level of IL‐33 during acute phase was associated with more past attacks in patients with NMOSD.