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

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

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.

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.

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.