Elevated serum levels of interleukin-17A in uveitis patients

Abstract

Purpose: T helper 17 cells (Th17) are one of the main pathogenic effectors in autoimmune uveitis, and IL-17A is the signature cytokine of Th17 cells. This study aims to assess serum IL-17A levels in patients with autoimmune uveitis and evaluate associations between IL-17A levels and disease characteristics.

Methods: Serum IL-17A levels from 87 autoimmune uveitis patients and 60 healthy controls were assessed using an enzyme-linked immunosorbent assay. Among this cohort, 9 patients were followed longitudinally for IL-17A levels during active and inactive stages of their disease.

Results: Median serum IL-17A levels were higher among uveitis patients compared to controls (p < 0.0001). Moreover, IL-17A levels were elevated among uveitis patients with active disease compared to those with inactive disease (p = 0.0202). Among the 9 patients followed longitudinally, IL-17A levels were elevated during active disease compared to the inactive stage (p = 0.0078).

Conclusions: Serum IL-17A levels are elevated in uveitis patients, particularly in active uveitis.

FIGURE 1

Serum IL-17A levels. (A) Median IL-17A levels were significantly increased among uveitis patients (27.26 pg/mL; 95% CI: 22.07–35.05) compared to controls (9.17 pg/mL; 95% CI: 7.51–10.84) (p<0.0001). (B) Median IL-17A was higher in patients with active disease (36.35 pg/mL; 95% CI: 27.26–51.93) compared to patients with inactive disease (24.27 pg/mL; 95% CI: 16.88–31.16) (p = 0.0202). Both inactive and active patients had higher levels of IL-17A compared to controls (p<0.0001). (C) When distinguishing between patients with minimal to no disease activity, both inactive (24.67 pg/mL; 95% CI: 18.18–33.76) and slightly active patients (18.18 pg/mL; 95% CI: 6.49–45.44) had decreased IL-17A levels compared to highly active patients (36.35 pg/mL; 95% CI: 27.26–51.93) (p = 0.0323, p = 0.0420). Kruskal-Wallis tests were used to compare groups. * and **** indicate the statistically significant p value <0.05 and 0.0001, respectively.

FIGURE 2

Median serum IL-17A levels were significantly higher during the active phase (27.26 pg/mL; 95 CI: 16.88–41.54) compared to the inactive phase (15.58 pg/mL; 95 CI: 9.09–36.35) of the disease among the 9 patients followed longitudinally (**p = 0.0078). A Wilcoxon matched-pairs test was used to compare the means between visits.