(A) The study outline showing when bloods were drawn, skin tests were performed, and DPC treatment was applied during the ~24 weeks of participation in the study. The four time points at which sensitization scores were recorded and blood samples were taken are referred to throughout the paper as PS (pre-sensitization, week 0), PT1 (Patch Test 1, week 2), PT2 (Patch Test 2, week 6) and PT3 (Patch Test 3, around week 24). In all cases bloods were drawn prior to application of the patch test. (B) and (C) The PS and PT1 blood samples of 10 patients were analyzed using flow cytometry. The mean percentage of total naive, central memory (CM), effector memory (EM), and effector memory RA (EMRA) expressing cells in the (B) CD4 and (C) CD8 compartments are shown. Paired t-tests with Benjamini–Hochberg correction for multiple testing were performed to check for significant differences between the pre- and post-sensitization cell number distributions for each subpopulation. All p-values were considerably higher than the 0.05 significance threshold. (D) The Shannon diversity index of the healthy volunteers (n = 15 samples from five individuals), pre-sensitization (n = 25), and post-sensitization (n = 58; from all three time points) TCR repertoire samples. All samples were randomly subsampled to the minimum sample size (21,838 beta TCRs), and the Shannon diversity index of the subsample was then calculated. Each sample is represented by a dot. The box plots show the median, and lower and upper quartiles of each group. Differences in the distribution of the three groups were tested using a Kruskal–Wallis rank sum test and were non-significant (p=0.87). (E) The Gini inequality coefficient of the healthy volunteers, pre-sensitization and post-sensitization TCR repertoire samples, subsampled as in (D). Differences in the distribution of the three groups were tested using a Kruskal–Wallis rank sum test and were non-significant (p=0.89). (F) The number of TCRs that appear with a frequency of 1/1000 or higher in each sample (termed ‘abundant TCRs’), for the healthy volunteers, pre-sensitization and post-sensitization samples, subsampled as in (D) and (E). A Kruskal–Wallis rank sum test revealed no statistical difference between the groups (p=0.14). (G)– (I) Sensitized samples were separated according to time point: PT1 (n = 23), PT2 (n = 18), and PT3 (n = 17). The Shannon diversity index (G), the Gini coefficient (H), and the number of abundant clones (I) of these subsamples were then calculated. Kruskal–Wallis rank sum tests were used to compare between the three groups in each case. All tests showed no statistically significant difference, with p-values p=0.97, p=0.96, and p=0.90 respectively.