Cytokine patterns in vitro, in particular IL-5/IL-8-ratio, to detect patients with nickel contact allergy

Abstract

Background

Patch test (PT) is the gold standard to reveal Nickel (Ni) allergy. In vitro tests are under discussion. We aimed to establish a cytokine based in-vitro assay to detect Ni sensitization.

Methods

From 15 patients with positive (13f, 42-78yrs) and 15 with negative PT to Ni (controls, 3f, 31-82yrs) within a consecutive patient series peripheral blood mononuclear cells (PBMC) were obtained. 6 days stimulation with 3 concentrations of NiSO₄ was done. Proliferative response (uptake of tritiated thymidine) and production of the cytokines IL-1β, IL-4, IL-5, IL-6, IL-8, IL-10, IL-17A, TNFα, IFNγ (cytometric bead array) were assessed.

Results

12/15 Ni PT positive patients also had positive LTT, all control patients were PT and LTT negative. The mean SI differed between Ni allergics and controls (p<0.01). Upon Ni stimulation, PBMC of the allergic patients showed (i) enhanced IL-5 response (p<0.0001) and (ii) reduced IL-8 production (p<0.01). The IL-5/IL-8-ratio best distinguished allergics from non-allergics in all 3 Ni concentration with a sensitivity and specificity of 93%.

Conclusion

Assessment of the ratio of Ni induced IL-5 and reduced IL-8 production in vitro is a helpful tool for a better characterization of Ni allergic patients.

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