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Background: The atopy patch test (APT) is an in vivo model to study the induction of eczema by inhalant allergens in atopic dermatitis patients. We studied the effect of pretreatment with topical tacrolimus 0.1% on APT in nonlesional skin of patients with atopic dermatitis. Methods: Nonlesional skin of the back of patients with atopic dermatitis ( n = 8) was treated once daily for 3 weeks with tacrolimus 0.1% ointment. Cetomacrogol ointment (placebo) was used as a negative control and triamcinolone acetonide 0.1% ointment as positive control. Twenty-four hours after the last APT application, samples were taken from the three treated areas ( t = 0 and 24 h) for immunohistochemical analysis. Results: Pretreatment with tacrolimus ointment did not suppress nonlesional skin infiltrate, in contrast to triamcinolone acetonide. Furthermore, tacrolimus did not inhibit the induction of the APT macroscopically ( t = 24 h). An equal influx of T cells, eosinophils, dendritic cells, CD64+ and Fc ℇRI-positive cells was present compared with placebo. Only CD36+ and CD68-positive cells were inhibited compared with placebo. All cell types were significantly inhibited in triamcinolone acetonide-treated sites compared with placebo. Conclusions: Pretreatment with tacrolimus 0.1% ointment does not inhibit the APT reaction in patients with atopic dermatitis. [ABSTRACT FROM AUTHOR]

IgE-binding peanut proteins smaller than 15 kDa were previously identified as potential allergens in the majority of our peanut allergic population.To characterize the novel allergen in order to determine whether it was similar to one of the thus far identified recombinant peanut allergens (Ara h 1–7).An IgE-binding protein of<15 kDa was purified and identified via N-terminal sequencing. Its IgE-binding properties were investigated using immunoblotting, basophil degranulation, and skin prick testing. Possible cross-reacting epitopes with other peanut allergens were studied using IgE-immunoblotting inhibition.The purified protein is a monomeric protein with a molecular weight of 14 981 Da as determined using matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectroscopy. The amino acid sequence of the first 39 N-terminal residues is identical to that of Ara h 6, indicating that the allergen is Ara h 6. It is recognized by 20 out of 29 peanut-allergic patients on IgE-immunoblot, and its potent biological functionality is demonstrated by the degranulation of basophils, even at concentrations below 10 pg/mL, and by positive skin prick reactions. Ara h 6 has homology to Ara h 2, especially in the middle part and at the C-terminal part of the protein. Almost complete inhibition of IgE–Ara h 6 interaction with Ara h 2 demonstrates that at least part of the epitopes of Ara h 6 are cross-reactive with epitopes on Ara h 2.Peanut-derived Ara h 6 is a biologically active allergen recognized by the majority of our peanut-allergic patient population and can be considered a clinically relevant peanut allergen. [ABSTRACT FROM AUTHOR]