CD4⁺ T cells from behcet patients produce high levels of IL-17

Abstract

Purpose: To investigate the role of interleukin (IL)-17-producing CD4⁺ T cells in Behcet disease (BD).

Methods: Blood samples were drawn from eight BD patients with active uveitis, eight BD patients with inactive uveitis and eight normal controls, respectively. PBMCs were prepared from heparinized blood by Ficoll-Hypaque density-gradient centrifugation. Peripheral CD4⁺ T cells were purified by Human CD4 Microbeads (MACS). The purity rate of CD4⁺ T cells was detected using flow cytometry. Purified CD4⁺ T cells were stimulated with or without anti-CD3 and anti-CD28 antibodies in the presence or absence of recombinant-IL-23 (rIL-23) or recombinant-IL-12 (rIL-12) for 72 hours. The concentrations of IL-17, IFN-γ and IL-4 in the collected supernatants from CD4⁺ T cells were measured using a Duoset ELISA Development kit.

Results: The results showed that the levels of IL-17 and IFN-γ observed in active BD patients were significantly higher as compared with those in inactive patients and normal controls. There was no significant difference concerning IL-4 production between BD patients and normal controls. rIL-23 significantly augmented the production of IL-17 by CD4⁺ T cells from both BD patients and normal controls. Both rIL-23 and rIL-12 could increase IFN-γ production by CD4⁺ T cells from BD patients and normal controls. Moreover, the effect of rIL-12 was more robust compared with that of rIL-23. Neither rIL-23 nor rIL-12 exerted any effect on IL-4 production.

Conclusion: rIL-23 can promote the production of IL-17 by CD4⁺ T cells in BD patients. The upregulated IL-17 levels may be related with the intraocular inflammation of Behcet patients.