To analyse further the possible differences in gene expression between RO4929097 purchase psoriasis patients and healthy controls, probe sets from psoriasis patients with negative elicitation reactions as well as healthy individuals, also with a negative elicitation reaction, were selected for further analysis using the t-test and subsequent correction for multiple testing with Bonferroni’s adjustment. Sensitization ratios were lower in both the psoriatic and diabetic groups compared to the healthy subjects group. The sensitization ratio was 26% (3:23) for the psoriatic group, 36% (8:22) for the diabetic group and 65% (15:23) for the

healthy control group (Fig. 1). The logistic regression analysis for a psoriasis patient gave an OR of being sensitized buy LEE011 to 0·18 (95% CI: 0·039–0·85), P = 0·031, when adjusted for sex and age. The crude OR of being sensitized for a diabetes type I patient was 0·74 (95% CI: 0·548–1·008), P = 0·056. The percentage increase in dermal thickness, as measured by ultrasound, correlated well with the dose-dependent clinical scores of the visual assessment, and a linear

dose-dependent increase in response to DPCP was seen in all positively sensitized individuals. The overall strength of the elicitation responses of positively sensitized individuals is summarized in Table 1. For sensitized individuals there were no statistically significant differences in strength of elicitation between the groups. The challenge doses used did not show any irritant response in unsensitized individuals. In all five biopsies from subjects with a positive elicitation reaction, including healthy controls and psoriasis patients, a typical histological pattern of allergic contact dermatitis was present. Apart from one single outlier, all five biopsies had a grade 4 infiltration of CD4+, CD8+ and FoxP3+ cells, as demonstrated in Fig. 2. CD4+ cells and FoxP3+ were distributed mainly in the dermis, with only scattered cells in the epidermis. CD8+ cells were also found mainly in the dermis, but with a higher degree of infiltration in the

epidermis. The outlier was a healthy subject Ergoloid with a severe clinical reaction; her biopsies were with grade 4 infiltrations of CD8+ cells, but with very few CD4+ or FoxP3+ cells. The six biopsies from subjects with negative elicitation reactions all showed a histological picture of healthy skin; hence, there were no signs of subclinical reactions. All had a grade 1–2 degree of CD4+ cells, but no CD8+ cells and only a limited number of FoxP3+ cells. No distinction between biopsies from healthy controls and psoriasis patients could be made from the infiltration of T cells in patients with either a positive or negative elicitation reaction. The whole data set and subsets thereof were subjected to PCA. Figure 3 depicts a score plot of the first two principal components of the PCA with DPCP-treated skin biopsies only. The first two dimensions retained 22 and 11% of the variation in the data set, respectively.