Exploratory evaluation of tolerability, performance, and cosmetic acceptance of dexpanthenol-containing dermo-cosmetic wash and sun-care products for tattoo aftercare.

Background and Aims: Tattoo prevalence has significantly increased over the last decades. Proper tattoo aftercare, such as cleansing, moisturizing, and protection against sunlight, is essential to prevent complications and to keep the beauty of the tattoo. The tolerability, performance, and cosmetic acceptability of two dexpanthenol-containing dermo-cosmetic products, a wash and a sun-care, were investigated on tattooed skin in two separate trials. Methods: Two single-center, exploratory, open-label cosmetic studies were conducted between August and November 2020 to evaluate the dexpanthenol-containing dermo-cosmetic products. In the first study, healthy adults applied the 2.5% dexpanthenol-containing wash right after their tattoo session daily for 14 consecutive days. In the second study, healthy adults applied the 2.5% dexpanthenol-containing sun-care sun protection factor 50+ cream on existing tattoos that were daily exposed to sunlight for 28 consecutive days. Clinical examination by a dermatologist and self-assessment through subject questionnaires were used to assess the tolerability, acceptance, ease of use, and cosmetic outcomes of both products. Additionally, transepidermal water loss and moisturization assessments were performed to evaluate skin hydration after use of the sun-care product. Results: Both study products were well tolerated, and no product related adverse events were reported during the studies. At least 90% of the study participants appreciated the performance of the dexpanthenol-containing wash and sun-care product, including moisturizing properties, relief of unpleasant sensations, and preservation of the cosmetic appearance of the tattoo. For the sun-care, it was shown that its application supported maintaining the skin barrier of tattooed skin, while keeping it hydrated. Conclusion: The 2.5% dexpanthenol-containing wash and sun-care products are well tolerated and appreciated by tattooed subjects. Hence, they represent valid options for tattoo aftercare in line with current recommendations and practice.

Evidence for a TCR affinity threshold delimiting maximal CD8 T cell function.

Protective adaptive immune responses rely on TCR-mediated recognition of Ag-derived peptides presented by self-MHC molecules. However, self-Ag (tumor)-specific TCRs are often of too low affinity to achieve best functionality. To precisely assess the relationship between TCR-peptide-MHC binding parameters and T cell function, we tested a panel of sequence-optimized HLA-A(*)0201/NY-ESO-1(157-165)-specific TCR variants with affinities lying within physiological boundaries to preserve antigenic specificity and avoid cross-reactivity, as well as two outliers (i.e., a very high- and a low-affinity TCR). Primary human CD8 T cells transduced with these TCRs demonstrated robust correlations between binding measurements of TCR affinity and avidity and the biological response of the T cells, such as TCR cell-surface clustering, intracellular signaling, proliferation, and target cell lysis. Strikingly, above a defined TCR-peptide-MHC affinity threshold (K(D) < approximately 5 muM), T cell function could not be further enhanced, revealing a plateau of maximal T cell function, compatible with the notion that multiple TCRs with slightly different affinities participate equally (codominantly) in immune responses. We propose that rational design of improved self-specific TCRs may not need to be optimized beyond a given affinity threshold to achieve both optimal T cell function and avoidance of the unpredictable risk of cross-reactivity.

Cross-reactivity patterns of T cells specific for iodinated contrast media.

BACKGROUND: Approximately 3% of patients exposed to iodinated contrast media develop delayed hypersensitivity reactions. OBJECTIVE: We wanted to better understand the molecular basis of contrast media cross-reactivity. METHODS: Cross-reactivity was assessed by skin testing and measurement of T-cell activation (CD69 upregulation) and proliferation ((3)H-thymidine uptake, 5,6-carboxyfluorescein diacetate succinimidyl ester staining) of PBMCs, T-cell lines, and T-cell clones of 2 patients with delayed hypersensitivity reactions to iohexol and iomeprol, respectively. Thirteen different contrast media and potassium iodide were compared. RESULTS: Skin testing and analyses of PBMCs, T-cell lines, and clones showed broad cross-reactivity in both patients. Broad as well as more restricted cross-reactivity patterns were found in iohexol-specific and iomeprol-specific CD4(+) T-cell clones, whereas 1 iomeprol-specific CD8(+) T-cell clone showed no cross-reactivity at all. The reactivity to equimolar concentrations of iohexol and its dimer iodixanol was very similar, suggesting that the dimer was not more stimulatory than its monomer. Consistently low reactivity to iobitridol was found in both patients, but never to iodide. A frequency analysis of contrast medium-specific peripheral T cells gave values between 0.6 % (iomeprol) and 0.05 % (iobitridol). CONCLUSION: Clinically observed cross-reactivity between different contrast media is a result of the presence of contrast media-specific T cells, some of which show a broad cross-reactivity pattern. Iodide ions, known to be present at low concentration in contrast media solutions, do not seem to be the causative moiety. CLINICAL IMPLICATIONS: Detailed in vitro analysis might help identify noncross-reactive contrast media.