1. ¹The National Allergy Research Centre for Consumer Products, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
2. ²Department of Dermatology, Gentofte Hospital, University of Copenhagen, Copenhagen, Denmark
3. ³Department of Cellular and Molecular Medicine, The Panum Institute, University of Copenhagen, Copenhagen, Denmark

Correspondence: Dr Jørgen Olsen, Department of Cellular and Molecular Medicine, The Panum Institute Building 6.4., University of Copenhagen, DK- 2200 N, Denmark. E-mail: jolsen@imbg.ku.dk

Received 15 November 2006; Revised 2 April 2007; Accepted 6 April 2007; Published online 28 June 2007.

Abstract

Genes involved in the inflammatory response resulting in allergic contact dermatitis (ACD) are only partly known. In this study, we introduce the use of high-density oligonucleotide arrays for gene expression profiling in human skin during the elicitation of ACD. Skin biopsies from normal and nickel-exposed skin were obtained from seven nickel-allergic patients and five nonallergic controls at four different time points during elicitation of eczema. Each gene expression profile was analyzed by hybridization to high-density oligonucleotide arrays. Cluster analysis of 74 genes found to be differentially expressed in the patients over time revealed that the patient samples may be categorized into two groups: an early time-point group (no clinical reaction) and a late time-point group (clinical reaction). Bioinformatics analyses unraveled the potential involvement of signal transducers and activator of transcription and small/mothers against decepentaplegic (SMAD) transcription factors in the late time-point gene expression patterns. Concerning specific genes, the homeostatic chemokine CCL19 was unexpectedly found to be highly expressed in cells scattered in the deep dermis of the late time-point samples. Taken together, these findings suggest hitherto unknown roles of SMAD transcription factors and of CCL19 in the elicitation phase of ACD.