Search

Summary: Background: Knowledge about the required duration of exposure for elicitation of allergic nickel dermatitis in nickel‐allergic individuals is limited. However, it often has been proposed that short skin contact is safe. Objectives: To examine whether repeated skin contact with nickel over short time periods (3 × 10 min) can elicit allergic nickel dermatitis. Methods: Sixteen nickel‐allergic adults and 10 controls were exposed to, respectively, nickel‐ and aluminium‐containing discs on each volar forearm and on each earlobe for 3 × 10 min. One arm was pretreated for 24 h with sodium lauryl sulfate (SLS) 0·5% under occlusion before exposure. One aluminium and one nickel exposure site were clinically evaluated, and blood flow was measured with laser Doppler flowmetry at day 2 and day 4. Results: Ten of 16 (63%) nickel‐allergic participants developed allergic nickel dermatitis on SLS‐pretreated arm skin and three of 16 (19%) developed it on normal skin on the earlobe. On the SLS‐pretreated arms of nickel‐allergic participants, blood flow increased significantly more on the nickel‐exposed skin than on the aluminium‐exposed skin on days 2 and 4. No change in clinical reactivity or blood flow was found on normal forearm skin in nickel‐allergic participants or on any skin in controls. Conclusions: This experimental study showed that relatively short repeated skin contact (3 × 10 min) with metallic nickel elicits allergic nickel dermatitis in irritated skin and at sites with previous dermatitis. The results support the restrictions in current nickel regulation. What's already known about this topic? Repeated low‐dose nickel exposure may be a more potent trigger of allergic nickel dermatitis than less frequent exposure to a higher single dose.High nickel deposition onto skin can be measured after only seconds of direct skin contact.An impaired skin barrier may increase the risk of allergic nickel dermatitis. What does this study add? Relatively short repeated skin contact (3 × 10 min) with nickel has the potential to provoke allergic nickel dermatitis in irritated skin and at sites with previous dermatitis. Respond to this article Plain language summary available online [ABSTRACT FROM AUTHOR]

In spite of significant safety measures, allergy to industrial enzymes remains a major concern. The increasing prevalence of occupational allergy emphasizes the need to investigate the functional properties of enzyme-exposed dendritic cells (DCs), as DCs possess a potent ability to activate allergen-specific T cells.This study aims at elucidating the molecular mechanisms underlying allergic immune responses to lipase, an industrial enzyme. For this purpose, we studied the effect of both hypoallergenic and wild-type lipase on the transcriptional regulation in DCs and their stimulatory effect on memory CD4+ T cells.Five individuals with documented lipase allergy were tested for specific serum IgE. DCs from these individuals, stimulated with lipases, were assayed for their ability to affect proliferation and polarization of memory T cells. The effect of lipases on transcriptional activity in DCs was evaluated using global expression analysis.Lipase-specific IgE levels varied considerably between donors, with donor 4 exhibiting highest levels, and a potent specific CD4+ T cell recall response was demonstrated only for donor 4. No difference was detected in cytokine profile when T cells from donor 4 were co-cultured with DCs pulsed with either hypoallergenic or wild-type lipase, as demonstrated by high IL-4 and IL-13, and low IFN-γ production. However, the lipases induced different genetic signatures in DCs from donor 4, as compared with the non-responders.DCs from individuals with clinically diagnosed allergy to lipase displayed a differential response to stimulation with hypoallergenic and wild-type lipasein vitro. Only allergen-pulsed DCs from donor 4 were able to induce CD4+ T cell proliferation. The lipase-specific T cells displayed a T-helper type 2 phenotype, which was not altered by hypoallergenic lipase-pulsed DCs. Furthermore, DCs derived from donor 4 and stimulated with either of the lipases displayed different transcriptional profiles, as compared with the other donors. These signatures represent genes of potential importance for an immunoregulatory role of DC in an ongoing allergic response. [ABSTRACT FROM AUTHOR]