Background

Neuromyelitis optica spectrum disorder is an inflammatory astrocytopathy disorder of the central nervous system (CNS) which the interaction between T cells and B cells is suggested for its development. Interleukin 17 (IL-17) is one of the pro-inflammatory cytokines that could affect T cells activity. But there is a limited data on the serum levels of IL-17 in NMOSD patients.

Objectives

In this study we aimed to compare the serum levels of IL-17 as a pro-inflammatory factor in NMOSD patients and healthy subjects.

Methods

A population-based case-control study was conducted on 56 NMOSD patients and 100 healthy controls. NMOSD patients were selected from NMOSD specialist clinic of Sina hospital, which is a referral center for NMOSD in Tehran, Iran. NMOSD diagnosis was based on the 2015 international consensus criteria and only patients with NMO-IgG seropositive status were included in the study. Age and sex matched controls were gathered from healthy population from all municipality zones of Tehran. Serum levels of participants were assessed by the enzyme-linked immunosorbent assay (ELISA) test. The difference between the serum levels of IL-17 in case and control groups were evaluated by independent samples T-test and univariate model adjusted for age, gender and body mass index (BMI). Data distribution was not normal, so IL-17 levels are reported as Ln.

This study was supported by the National Institute for Medical Research Development (NIMAD) [grant number 973227].

Results

89.3% of participants in case group and 93.0% in control group were women. The mean (SD) ages of subjects in case and control groups were 35.89 (9.39) and 37.40 (6.68) years old, respectively (P: 0.29). No significant differences was found regarding BMI between study groups (BMI in case group: 26.61 ± 5.15; in control group: 26.82 ± 5.45 Kg/m² (P: 0.81)).

The mean (SD) levels of Ln serum IL-17 in NMOSD patients was 2.01 (1.18) pg/mL which was significantly higher than control group with the mean Ln serum levels of 1.11 (0.81) pg/mL (P <0.001). This difference was also significant in univariate model adjusted for age, gender and BMI (P <0.001).

Conclusions

This investigation suggested the possible role of IL-17 in NMOD development and also elevated serum level of IL-17 as a diagnostic criteria for NMOSD.