Multiplex Bead Analysis of Cytokines in Serum From Patients With Behcet's Disease

Abstract

Abstract: : Purpose: Behcet’s disease (BD) is a chronic, multisystem, vasculitic disorder. At present there is no laboratory test to diagnose the onset of BD, it's manifestations or to quantify its activity or response to treatment. Cytokines have been implicated in the pathogenesis of BD, but previous data on the interrelationship of these molecules in serum from patients have produced conflicting Results: We have analysed several cytokines in a single serum sample to identify profiles that may be disease specific, or associated with disease activity or treatment. Methods: Serum levels of nine cytokines were measured in samples from 104 patients with BD, 20 patients with recurrent aphthous stomatitis (RAS) and 15 healthy controls using the Luminex Bead analysis system. Levels of IL–15 were measured separately in the same samples by ELISA. Disease activity data was available on 78 BD patients and treatment data was available for 71. Results: In BD sera IL–8 was found in 69% of samples (range 2–1366 pg/ml), while IL–6 and TNF were found in 21% (2–1010 pg/ml) and 26% (2–152 pg/ml) of samples respectively. There was a significant correlation between levels of IL–8 and IL–6 (p=0.001). GM–CSF, IL–12 and IL–1ß were detected in 12% of samples. IL–2, IL–4, IL–10 and IFNγ were found at low levels in a few samples. Sera that contained TNF also contained IL–6 and IL–8. In patients with RAS and healthy controls, IL–4, IL–8, IL–10 or TNF could not be detected, but IL–1ß, IL–2, IL–6, IL–12, IFNγ and GM–CSF were found in few samples at low levels (<20 pg/ml). Serum levels of IL–15 were found to be raised in BD patients (mean 58.3 pg/ml; p<0.001), and even more so in RAS patients (mean 207.5 pg/ml; p<0.01) compared with normal healthy controls(6 pg/ml). Surprisingly, levels of IL–8, IL–6 Il–15 and TNF were lower in patients with active compared to inactive disease. Conclusions: The cytokine profile detected in the sera of BD patients was consistent with that seen in an innate rather than an adaptive immune response. The highest levels of cytokine did not correlate with disease activity.

Keywords: cytokines/chemokines • inflammation • uveitis-clinical/animal model