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Simultaneous Sensitization (simultaneous + sensitization)

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Medical Sciences	100%

Selected Abstracts

Lipoteichoic acid from Staphylococcus aureus enhances allergen-specific immunoglobulin E production in mice

CLINICAL & EXPERIMENTAL ALLERGY, Issue 6 2003
K. Matsui
Summary Background Our previous study demonstrated that lipoteichoic acid (LTA) from Staphylococcus aureus induced T helper type 2 (Th2)-prone dermatitis resembling that seen in atopic dermatitis (AD) patients in mice sensitized percutaneously with an allergen. However, the effects of LTA on allergen-specific IgE production in such sensitized mice have not been elucidated. Objective The purpose of this study was to determine the effects of LTA from S. aureus on allergen-specific IgE production in mice sensitized percutaneously with a house dust mite antigen (MA). Methods Mice were sensitized with a single topical application of MA and/or LTA to barrier-disrupted abdominal skin. One to 5 weeks later, MA-specific IgE antibodies in sera from sensitized mice were detected by an enzyme-linked immunosorbent assay (ELISA). Expression of B7.1 (CD80), B7.2 (CD86) and CD40L molecules by CD40-positive (CD40+) and CD4-positive (CD4+) cells in the lymph nodes of sensitized mice were analysed by flow-cytometry (FACS). Results Simultaneous sensitization with MA and LTA increased IgE production 3 weeks later, significantly more than sensitization with MA alone. FACS analysis of CD40+ cells in the lymph nodes from sensitized mice showed that simultaneous sensitization with MA and LTA did not enhance CD80- or CD86-expression by antigen-presenting cells such as B lymphocytes and dendritic cells more than sensitization with MA alone. However, analysis of CD4+ cells in the lymph nodes showed that simultaneous sensitization with MA and LTA increased the number of CD40L-expressing Th cells more than sensitization with MA alone. Conclusion These results suggest that LTA enhances allergen-specific IgE production by a mechanism associated with up-regulation of CD40L-expressing Th cells and this might explain the role of skin colonization with S. aureus in AD patients. [source]

Cross-reactivity between nickel and palladium demonstrated by systemic administration of nickel

CONTACT DERMATITIS, Issue 1 2005
M. Hindsén
Concomitant patch test reactions to nickel and palladium have frequently been reported in patients undergoing investigation because of suspected allergic contact dermatitis. Theoretically, these reactions can be explained by multiple, concomitant, simultaneous sensitization as well as cross-sensitization. We studied whether concomitant reactions to nickel and palladium could represent cross-sensitization in females hypersensitive to combinations of nickel, palladium and cobalt. Females were patch tested with serial dilutions of nickel sulfate, cobalt chloride and palladium chloride on the upper back. 1 month later, when the patch test reactions were gone, the patients were randomized into 2 groups that were challenged orally with either nickel or placebo. 1 day later, the areas of previous positive patch test reactions were read in a blind way looking for flare-up reactions. Nickel provocation but not placebo yielded flare-up reactions on sites previously tested with nickel (P = 0.012) and palladium (P = 0.006), but were also observed on sites previously tested with cobalt, even though this was not statistically significant. Flare-up reactions of previous patch test reactions to nickel and palladium after oral challenge with nickel speak in favour of a cross-reactivity mechanism. [source]

Simultaneous sensitivity to fragrances

BRITISH JOURNAL OF DERMATOLOGY, Issue 5 2006
D.A. Buckley
Summary Background, Cinnamal/cinnamic alcohol and isoeugenol/eugenol are pairs of related fragrance chemicals found in Fragrance Mix I (FM I), and thus are routinely tested in combination with other fragrances in the European standard patch test series. Their close structural similarity makes the occurrence of simultaneous sensitivity within these chemical pairs likely, although at present there are no robust data to support this hypothesis. Objectives, To establish the frequency of simultaneous reactions to these fragrance chemicals in patients with suspected fragrance allergy attending a contact dermatitis clinic; to provide evidence in support of proposed metabolic pathways; and to determine whether including all four separately in FM I is necessary to avoid missing a diagnosis of fragrance allergy. Methods, We analysed retrospectively the records of patients patch tested to the European standard series during the 15-year period 1984,98 for positive reactions to FM I. In a subset of patients tested to the constituents of FM I, positive reactions to cinnamal, cinnamic alcohol, isoeugenol and eugenol were sought. Data were analysed using 2 × 2 contingency tables (Fisher's exact test). Results, During this period, 23 660 patients were tested to the European standard series, of whom 1811 (7·7%) had positive reactions to FM I. Of the 1112 patients tested to the constituents of FM I, 934 had positive reactions to at least one constituent (total 1324 positive reactions to constituents). Of these 934, 826 also had positive reactions to FM I itself; 108 were negative to FM I but reacted to one or more of its constituents. One hundred and seventy-eight patients did not react to any of the breakdown constituents of FM I; 34 of these had positive reactions to FM I itself. Of 139 patients allergic to cinnamic alcohol, 87 were also allergic to cinnamal (63%), compared with 108 (11·1%) of 973 cinnamic alcohol-negative patients (P < 0·00001). Of 231 patients allergic to isoeugenol, 50 were also allergic to eugenol (22%), vs. 109 (12·4%) of 881 isoeugenol-negative patients (P = 0·0002). Conclusions, These data support in vitro experiments indicating that cinnamal and cinnamic alcohol may generate a common hapten and are consistent with the view that simultaneous sensitization to isoeugenol and eugenol occurs to a limited extent, despite their being metabolized via different pathways. In view of the substantial number of isolated reactions to each of these fragrance chemicals, all four should continue to be included separately as constituents of FM I. [source]