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

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.

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.

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).

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.