Atopic dermatitis responses

Clinically unaffected skin in atopic dermatitis differs from normal skin the underlying barrier defect associated in more than 30% with filaggrin loss of function mutations first published in 2006 [4] leads to dry skin associated with a greater irritant skin response than in normal healthy skin. Microscopic studies revealed a sparse perivascular T cell infiltrate in unaffected atopic dermatitis skin that is not seen in normal healthy skin. 

Role of Adaptive Immune Responses in Atopic Dermatitis Involving IgE Responses In about 80% of adult patients with atopic dermatitis, the disease is associated with increased serum IgE levels, sensitization against aeroallergens... 

Food-Specific T Cells Are Involved in Allergic Responses in Atopic Dermatitis in Children and Adults... 

Patients sensitized to pollen allergens often develop an IgE response to cross-reactive food allergens. Birch pollen-related food may lead to an exacerbation of eczema in a subpopulation of patients with atopic dermatitis and sensitization to birch pollen allergens. A birch pollen-specific T-cell response could be detected in lesional skin of these responding patients. T-cell cross-reactivity between Bet v 1 and related food allergens can occur independently of IgE cross-reactivity in vitro and in vivo. This has been shown in atopic dermatitis patients who developed late eczematous skin reactions to cooked food which was shown to elicit T-cell but not IgE-mediated responses [11]. 

T Cells May Contribute to the Defects in Innate Immune Response in Atopic Dermatitis Most patients with atopic dermatitis are colonized with S. aureus and experience exacerbation of their skin disease after infection with this organism [2]. In patients with S. aureus infection, treatment with anti-staphylococcal substances can result in the reduction of skin disease. Binding of S. aureus to the epidermis is enhanced by atopic skin inflammation. This is supported by clinical studies demonstrating that treatment with topical corticosteroids or tacrolimus reduces S. aureus counts in atopic dermatitis. 

In addition, some patients with atopic dermatitis produce specific IgE antibodies directed against staphylococcal superantigens, which correlate with skin disease severity. Superantigens have been shown to penetrate into the dermis and higher doses have been shown to induce cutaneous inflammation when applied onto the skin. Low doses which do not induce visible clinical inflammation are still able to amplify aeroal-lergen-induced patch test responses [14]. 

Are T Cells Involved in Specific Immune Responses to Autoantigens in Atopic Dermatitis Autoimmune phenomena to human self-proteins may also contribute to the pathophysiology of atopic dermatitis. IgE against autoantigens such as Horn SI-4 have been shown to stimulate type 1 hypersensitivity reactions which in turn may contribute to the clinical cutaneous reactions in atopic dermatitis [15]. Autoallergens induce the proliferation of CLA+ autoreactive T cells derived... 

Th-2 Cytokines Have Numerous Effects on Cutaneous Cells in Atopic Dermatitis In acute eczema, IL-4 and IL-13 induce a variety of local responses such as the induction of the adhesion molecules on endothelial cells, of chemokines or of Fc receptors on eosinophils [1]. Recent findings point to direct effects of IL-4 and... 

Werfel T, Breuer K, Rueff F, Przybilla B, Worm M, Grewe M, Ruzicka T, Brehler R, Wolf H, Schnitker J, Kapp A Usefulness of specific immunotherapy in patients with atopic dermatitis and allergic sensitization to house dust mites a multicentre, randomized, dose-response study. Allergy 2006 61 202-205. 

Pruritus Relief of inflammatory and pruritic manifestations of corticosteroid-responsive dermatoses Contact dermatitis, atopic dermatitis, nummular eczema, stasis eczema, asteatotic eczema, lichen planus, lichen simplex chronicus, insect and arthropod bite reactions, first- and second-degree localized burns, and sunburns. 

Majamaa, H., Seppala, U., Palosuo, T., Turjanmaa, K., Kalkkinen, N., Reunala, T. (2001). Positive skin and oral ehallenge responses to potato and occurrence of immunoglobulin E antibodies to patatin (Sol 11) in infants with atopic dermatitis. Pediatr. Allergy Immunol., 12,283-288. 

It is an immunosuppressant macrolide antibiotic produced by Streptomyces tsukubaensis. Like cyclosporine, tacrolimus binds to a cytoplasmic immunophylin and the complex inhibits the activity of the calcium dependent phosphatase known as calcineurin. This in turn, inhibits the translocation of the transcription factor NF-AT into the cell nucleus, blocking the initiation of NF-AT dependent T-cell responses. It is indicated in atopic dermatitis. 

There are several genetic skin diseases with known defects in the lipid metabolism. Atopic dermatitis, lamellar ichthyosis, and psoriasis have been the most widely studied with respect to epidermal barrier function and alterations in the lipid profile. Deviations in the lipid profile have been linked with an impaired stratum corneum barrier function. Atopic dermatitis is characterized by inflammatory, dry and easily irritable skin, and overall reduced ceramide levels in the stratum corneum [58-60]. In particular a significant decrease in the ceramide 1 level is observed, whereas the levels of oleate that is esterified to ceramide 1 are elevated [59]. Both aberrations may be responsible for the reduced order of the lamellar phases as observed with freeze fracture electron microscopy [61]. It has further been established that, in comparison to healthy stratum corneum, the fraction of lipids forming a hexagonal packing is increased [61]. A recent study reveals that the level of free fatty acids... 

Miyamoto et al. have also demonstrated in the dry skin and itch mouse model (water + acetone ether treated) that the scratching response can be inhibited by the use of atropine, a nonspecific muscarinic acetylcholine receptor (mAChR) antagonist, and 4-diphenyl-acetoxy-N-methyl-piperidine (4-DAMP), an M3 mAChR antagonist.32 They further showed that Mi and M2 mAChR antagonist were not able to inhibit the scratch response. This report suggests the role of acetylcholine, and the M3 specific receptor as a potential player in dry-skin-associated pruritus. In addition, skin biopsies in human subjects with atopic dermatitis were found to have increased levels of acetylcholine compared with normal controls, which suggests that abnormal concentrations of neurotransmitters may also be involved in itch secondary to xeroderma.33... 

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