st statistic reflects a biologist’s view that a gene with a greater fold change than other genes is potentially the more interesting one. Also, given two genes with the same fold changes, it is the gene with a higher expression level that is the more interesting one. Genes were subsequently LGX818 organized into functional groups and their expression patterns displayed as a heatmap. Array data have been deposited in the EBI Array Express Database. Quantitative real-time PCR analysis Relative mRNA transcript levels were measured by real-time quantitative reverse transcription PCR in a LightCycler 480. Total RNA was reverse transcribed using the Roche Transcriptor Kit and 50 ng cDNA were quantified using LightCycler 480 Probe Master Kit. Duplicate biological samples were used. Each sample was run as a technical duplicate and mean values were reported. Normalized gene expression values were obtained using LightCycler Relative Quantification software. Relative gene copy numbers were derived by efficiency-corrected relative quantification 
using the formula 2DCT, where DCT is the difference in amplification cycles required to detect amplification product from equal starting concentrations of RNA. The sequences of the oligonucleotide primers and the corresponding Universal Probe Library probe were supplied by Roche Applied Science. Results were expressed as fold change compared with the Veh/veh-treated animals. Histological analysis For histological examination, ear specimens were fixed in 10% buffered formalin and embedded in paraffin. Fourmicron sections were stained with hematoxylin and eosin. For immunohistochemistry, ears were frozen in OCT medium in a dry ice/ 83 isopentane bath. Ears were subsequently sectioned and stained with ratanti-mouse GR-1 followed by an anti-rat antibody conjugated to alkaline phosphate and coverslipped using Vectashield Mounting Medium. Human skin was obtained by surgical removal from healthy, control patients after written consent and approval by the local ethics committee. The human skin was frozen in OCT, sectioned and stained with a rabbit anti-human CRTH2 polyclonal antibody. An anti-rabbit antibody conjugated to HRP was used for visualization of CRTH2. Control sections were stained with either a nonantigen-specific rabbit polyclonal primary antibody followed by the secondary antibody or the secondary antibody alone. All slides were imaged using a Zeiss Primostar microscope, a Moticam 2000 camera Motic Images Plus 2.0 software. Statistics The data are presented as the mean values 6 SEM, unless stated otherwise. Statistical differences between data sets were analyzed by one-way analysis of variance and differences between groups were determined by Student’s t-test. Statistics were computed by GraphPad Instat 3 software. P values <0.05 were considered statistically significant. Results CRTH2 antagonist blocks FITC-induced ear swelling To examine the role of the CRTH2 receptor in cutaneous inflammation, we used an allergic contact dermatitis model in which mice are sensitized to FITC on days 1 and 2 and 6 days later are challenged by FITC application to the right ear. The left ear serves as a control because it is treated with an equal amount of the FITC Veh. This experimental system has similarities to AD in humans, as it is CD4+ T lymphocyte dependent, and much of the pathology seen PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/19826115 is analogous to acute AD lesions. We first investigated whether the administration of a specific, potent CRTH2 antagonist, Cmpd A, co