Supplementary Material for: Luminex LiquiChip System for the Evaluation of Cytokine Levels in Patients with Contact Dermatitis to Potassium Dichromate

<p><b><i>Background:</i></b> Allergic contact dermatitis (ACD) is associated with increased production of cytokines. The patch test is the “gold-standard” diagnostic method, but it poses a risk of false results. <b><i>Objective:</i></b> To evaluate a novel laboratory technique, the Luminex LiquiChip, which simultaneously measures blood levels of multiple cytokines, as a diagnostic tool in patients with chrome-induced ACD. <b><i>Methods:</i></b> The study group included 20 patients with ACD and relevant patch test results for potassium dichromate and 19 patients with ACD for nickel or fragrance as control. Peripheral blood mononuclear cells (PBMCs) were cultured in the presence and absence of potassium dichromate. The Luminex LiquiChip was used to measure levels of the following cytokines: granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, interferon-γ, and tumor necrosis factor (TNF)-α. <b><i>Results:</i></b> Potassium dichromate-stimulated PBMCs secreted significantly higher amounts of all cytokines except TNF-α than nonstimulated PBMCs. PBMCs from patients with ACD to chromium secreted significantly higher amounts of all cytokines tested, except IL-4, compared to PBMCs from patients with ACD to nickel or fragrance. <b><i>Conclusions:</i></b> Potassium dichromate stimulates the production of both Th1- and Th2-type cytokines in patients with chrome allergy. The Luminex LiquiChip is a promising in vitro method and may serve as a diagnostic tool for ACD.</p>