The desmosome and pemphigus

Desmosomes are patch-like intercellular adhering junctions (“maculae adherentes”), which, in concert with the related adherens junctions, provide the mechanical strength to intercellular adhesion. Therefore, it is not surprising that desmosomes are abundant in tissues subjected to significant mechanical stress such as stratified epithelia and myocardium. Desmosomal adhesion is based on the Ca2+-dependent, homo- and heterophilic transinteraction of cadherin-type adhesion molecules. Desmosomal cadherins are anchored to the intermediate filament cytoskeleton by adaptor proteins of the armadillo and plakin families. Desmosomes are dynamic structures subjected to regulation and are therefore targets of signalling pathways, which control their molecular composition and adhesive properties. Moreover, evidence is emerging that desmosomal components themselves take part in outside-in signalling under physiologic and pathologic conditions. Disturbed desmosomal adhesion contributes to the pathogenesis of a number of diseases such as pemphigus, which is caused by autoantibodies against desmosomal cadherins. Beside pemphigus, desmosome-associated diseases are caused by other mechanisms such as genetic defects or bacterial toxins. Because most of these diseases affect the skin, desmosomes are interesting not only for cell biologists who are inspired by their complex structure and molecular composition, but also for clinical physicians who are confronted with patients suffering from severe blistering skin diseases such as pemphigus. To develop disease-specific therapeutic approaches, more insights into the molecular composition and regulation of desmosomes are required

Patch tests in children: A review of 13 years of experience in comparison with previous data

The true prevalence of allergic contact dermatitis (ACD) in children remains unknown. Our aim was to compare the results of patch tests in children with suspected ACD between two different periods of time and identify possible changes in emerging allergens. We compared contact allergens, gender, age distribution, and personal history of atopic dermatitis (AD), in correlation with the positivity of patch tests, between two equal periods of time (232 children tested during 1980-1993, period A, and 255 children during 1994-2007, period B) in the same region and in the same institution. Patch test positivity was 47.8% in period A, and 60% in period B (p = 0.083). The most common allergens in period A were: nickel sulfate (16.3%), cobalt chloride (8.6%), fragrance mix (7.3%), potassium dichromate (4.3%), and thimerosal only (1.7%). In period B, the allergen distribution was as follows: nickel sulfate (21.56%), thimerosal (18.03%), cobalt chloride (12.9%), potassium dichromate (9.4%), and fragrance mix (4.7%). Girls were more likely to have a positive patch test compared with boys, with reactions in 53% of girls and 39% of boys in period A (p = 0.003), and 61% of girls and 58% of boys in period B (p = 0.691). Twenty-nine per cent of patients with positive results had a personal history of AD in period A and 44% in period B (p = 0.015). Differences in the positivity of allergens between different time periods reflect changes in habits, of allergens exposure or preventive measures. © 2010 Wiley Periodicals, Inc