IL-13-Stimulated Human Keratinocytes Preferentially Attract CD4+CCR4+ T cells: Possible Role in Atopic Dermatitis

Skin inflammation in atopic dermatitis (AD) is characterized by the predominant infiltration of T-helper (Th)2-cells in lesional skin. However, the mechanism of recruitment of these cells in lesional skin of AD is not yet fully elucidated. In this study, we investigated the role of IL-13-stimulated human primary keratinocytes (HPKs) in the recruitment of lymphocytes and further delineated the mechanism of enrichment of these cells. In the migration assays, we observed preferential enrichment of CD4+CCR4+ T cells towards IL-13-stimulated HPKs. Interestingly, CD4+CCR4+ T cells from AD showed a higher chemotactic response than those from healthy individuals. We observed a significant increase in the expression of CCL22 in IL-13-stimulated HPKs as compared to unstimulated cells. Blocking of CCL22 in IL-13-stimulated HPKs by a neutralizing antibody resulted in 70–90% inhibition in migration of CD4+CCR4+ T cells. Moreover, IL-13 upregulated IFN-γ-induced chemokines, CCL2 and CCL5, in HPKs. Taken together, our data suggest that IL-13-stimulated HPKs participate in a positive feedback loop by preferentially enriching Th2-cells in lesional skin of acute AD patients. However, in chronic phase, IL-13 may act in synergy with IFN-γ resulting in lymphocytes recruitment of a mixed phenotype at the site of inflammation, thus contributing to the chronification of eczema

Role of Macrophages in the Pathogenesis of Atopic Dermatitis

Atopic dermatitis (AD) is one of the most common and most intensively studied chronic inflammatory skin diseases. Several cofactors, such as an impaired skin barrier function, modifications of the immune system, and a complex genetic background, direct the course of AD. Within this complex network, macrophages play a pivotal role in enhanced susceptibility to cutaneous infections and act as central connecting components in the pathogenesis of AD on the cellular level. In AD, macrophages are known to accumulate in acutely and chronically inflamed skin. During the early and short inflammatory phase, macrophages exert proinflammatory functions like antigen-presenting phagocytosis and the production of inflammatory cytokines and growth factors that facilitate the resolution of inflammation. However, persistence of pro-inflammatory activity and altered function of macrophages result in the development of chronic inflammatory diseases such as AD. The exact mechanism of macrophages activation in these processes is not yet completely understood. Further studies should be performed to clarify the dysregulated mechanism of macrophages activation in AD, and this would allow us to target these cells with versatile functions for therapeutic purpose and improve and control the disease. In this paper, we highlight the new findings on dysregulated function of macrophages and the importance of these cells in the pathogenesis of AD in general and the contribution of these cells in enhanced susceptibility against microbial infections in particular

The Antimicrobial and Immunomodulatory Function of RNase 7 in Skin

The human ribonuclease RNase 7 has been originally isolated from human skin and is a member of the human RNase A superfamily. RNase 7 is constantly released by keratinocytes and accumulates on the skin surface. The expression of RNase 7 in keratinocytes can be induced by diverse stimuli such as cytokines, growth factors, and microbial factors. RNase 7 exhibits a potent broad spectrum of antimicrobial activity against various microorganisms and contributes to control bacterial growth on the skin surface. The ribonuclease and antimicrobial activity of RNase 7 can be blocked by the endogenous ribonuclease inhibitor. There is also increasing evidence that RNase 7 exerts immunomodulatory activities and may participate in antiviral defense. In this review, we discuss how these characteristics of RNase 7 contribute to innate cutaneous defense and highlight its role in skin infection and inflammation. We also speculate how a potential dysregulation of RNase 7 promotes inflammatory skin diseases and if RNase 7 may have therapeutic potential

Therapy of atopic eczema

Objectives: Major objective is the evaluation of the medical effectiveness of different therapeutical approaches and the cost effectiveness with relevance for Germany. Methods: This health technology assessment (HTA) evaluates systemically randomized controlled studies (RCT) on the therapy of atopic dermatitis which were published between 1999 and 2004. Further it includes some important clinical studies which have been published after 2004 and other updates the English HTA report by Hoare et al. [1]. Results: Topical corticosteroids and topical calcineurin-inhibitors are the principal substances which are currently used for anti-inflammatory therapy in atopic dermatitis. These substances have shown a significant therapeutic efficacy in controlled studies. In newer controlled studies no difference was observable when corticosteroids were applied once or more than once daily onto the skin. Moreover, there is now one controlled study available which points to the fact that an interval therapy with a stronger topical corticosteroid over a limited time (some weeks) may lower the risk of recurrent flares of atopic dermatitis. Both topical calcineurin-inhibitors pimecrolimus and tacrolimus have shown a significant therapeutical efficacy in a number of placebo-controlled prospective studies. The wealth of data is high for these substances. Both substances have been shown to be efficient in infants, children and adult patients with atopic dermatitis. The importance of a so-called basic therapy with emollients which have to be adapted to the current status of skin is generally accepted in clinical practice. Controlled studies show the efficacy of ”basic therapy” - although the level of evidence is quite low for this approach. The skin of patients with atopic dermatitis is colonized in the majority with Staphylococcus aureus, a gram-positive bacterium. Therefore, a therapeutical approach for the treatment of atopic dermatitis is the anti-bacterial or anti-septic treatment of the skin. Due to the lack of randomized controlled studies there is still not certain proof that antimicrobial or anti-septic treatment of non-infected eczematous skin is efficient for the treatment of atopic dermatitis. A reduction of Staphylococcus aureus is observable during an anti-inflammatory treatment of the skin with topical corticosteroids and/or the topical calcineurin-inhibitor tacrolimus. Antihistaminic drugs which are orally applied in atopic dermatitis may support the therapy of the itching skin disease. One controlled study showed a rapid reduction of itch during the use of a non-sedating antihistaminic drug. There are, however, no controlled studies which show the efficacy of antihistaminic drugs on the skin condition in atopic dermatitis. Dietetic restrictions should be applied only after a specific allergological diagnostic clarification. The “gold standard” is still a (blinded) oral provocation test which has to show an influence of a given food on the skin condition. There is sufficient evidence that there is no general dietetic approach which shows efficacy in atopic dermatitis. The treatment of patients with lactobacillae is still controversially discussed. Available studies which showed an efficacy show methodological weaknesses so that this approach can not be generally recommended for clinical practice at the time now. Approaches reducing house dust mite in the surroundings of patients with atopic dermatitis can have an effect on the skin condition so that at least in mite sensitized patients this approach appears to be reasonable. The specific immunotherapy with house dust mite showed clinical efficacy in a controlled study and in some open studies. The education of patients with atopic dermatitis or their parents is a further efficient approach in the management of this chronic skin disease. Interdisciplinary approaches in patients’ education containing also psychological elements appear to be an attractive new approach for the treatment of atopic dermatitis. Phototherapy is a further possibility of intervention in atopic dermatitis in adolescent or adult patients. The available evidence points to the fact that UVB radiation (both small and broad spectrum), UVA-1 radiation and balneo-phototherapy are efficient therapeutical options for atopic dermatitis. The systemic treatment with the immunosuppressive substance cyclosporine A is efficient in the treatment of severe atopic dermatitis. Cyclosoprine A is approved for the treatment of adult patients with this skin disease. The immunosuppressive substance azathioprine showed a high clinical efficacy in two controlled studies for severe atopic dermatitis in adults. There are still controversial results for the application of antagonists to leucotriens in the treatment of atopic dermatitis: in some open studies a therapeutical efficacy was described which was, however, not reproducible in a newer controlled study. The phosphodiesterase-4-inhibitor cipamphyllin was efficient in the treatment of atopic dermatitis in a controlled study but weaker than a topical class II (i. e. moderate strength) corticosteroide. The HTA assessment further describes so-called complementary therapeutical approaches which have either not properly been studied in controlled clinical trials or which have been shown to be of no value for the treatment of atopic dermatitis. Altogether six full health-economic evaluations were found which did not cover the whole therapy spectrum of atopic dermatitis. The choice of the most cost effective treatment option of topic corticosteroids depends less on application frequency, but rather on the drug price and more used or unused quantity of the standard packages, so even smallest improvements justify a more frequent application. The results from health economic evaluations of calcineurin-inhibitors are not reliable. The therapy of severe atopic dermatitis in adults with ciclosporin shows comparable cost effectiveness in comparison to UVA/UVB therapy. Discussion: The spectrum of therapeutical procedures has increased for atopic dermatitis but is still not sufficient. The spectrum of established substances is much smaller compared to psoriasis, another chronic and common inflammatory skin disease. There is need for the development new substances which can be applied topically and which are aimed to treat atopic dermatitis in early childhood. Another need for new developments can be found for the treatment of severe atopic dermatitis in adults. Conclusions: The spectrum of therapeutical procedures has increased for atopic dermatitis but is still not sufficient. The spectrum of established substances is much smaller compared to psoriasis, another chronic and common inflammatory skin disease. There is need for the development new substances which can be applied topically and which are aimed to treat atopic dermatitis in early childhood. Another need for new developments can be found for the treatment of severe atopic dermatitis in adults. Due to lack of health economic evaluations therapy decisions in the treatment of atopic dermatitis must take place on the basis of clinical decision criteria. The prescription of topic corticosteroids should prefer low priced drugs. Reliable statements about the cost effectiveness of the new calcineurin-inhibitors tacrolimus and pimecrolimus

Therapy of moderate and severe psoriasis

Objective and methods: This health technology assessment (HTA) report synthesises systematically randomized controlled studies (RCT) on the therapy of moderate and severe psoriasis vulgaris which were published between 1999 and 2004; it includes some important clinical studies which have been published after 2004 and thus updates the English HTA report by Griffiths et al. [1]. The major objective is the evaluation of the medical effectiveness of different therapeutical approaches and the cost effectiveness with relevance for Germany. Results: The major conclusions from the results of medical RCT on moderate and severe psoriasis vulgaris are: Oral fumarates are effective in the treatment of moderate to severe psoriasis vulgaris. However, fumarates quiet frequently cause moderate side effects. Cyclosporine and methotrexate are both effective in the treatment of severe psoriasis vulgaris. Both substances have a different spectrum of side effects which may limit the individual applicability. Acetritin is only moderately effective in the treatment of severe psoriasis of the plaque type. Calcipotriol or UV-radiation used at the same time can increase the clinical effectiveness of acetritin. Systemic PUVA, balneo-PUVA and UVB therapy are all effective for the treatment of severe psoriasis. The combination of UV therapy with vitamin D3 analogues or with topical steroids is more effective than the treatment with UV radiation alone. Saltwater baths increase the effectiveness of UVB therapy. No RCT on the therapeutical effects of topical tar or of dithranol in combination with UV therapy have been published so far. A continuous therapy with PUVA should not be applied due to its proven photocarcinogenicity. Three substances from the group of biologicals (Efalizumab, Etanercept, and Infliximab) are now available in Europe and a further substance (Alefacept) is available in the USA for the treatment of moderate to severe psoriasis. All biologicals have been effective in placebo controlled studies. The substances differ in the times until a clinical effect is observable, in the spectrum of side effects and in their efficiency on psoriasis arthritis. From health-economic studies considering both costs and clinical efficiency oral fumarates appear to be superior to acitretin or cyclosporine (although cyclosporine appears to be more effective in severe psoriasis). From the health economic view methotrexate is equivalent with UVB or PUVA and superior to cyclosporine. The therapy options UVB, UVB plus calcipotriol and PUVA are equivalent and superior to balneo-phototherapy. Biologicals are cost intensive and should be used when other approaches are not sufficient or are not applicable due to their side effects. The HTA report summarizes some health-economic studies on dithranol, on calcipotriol and on the combination with tar and UV light. No RCT have been published for the treatment of severe psoriasis with these agents alone but it appears to be certain that these substances are effective in severe psoriasis as well.DiscussionThe spectrum of therapeutical options has fortunately increased during the last years. It must be emphasized that a number of therapeutical procedures exist which are not discussed in detail in this HTA. This is due to the search strategy of literature: Only RCT performed with patients with moderate and/or severe psoriasis vulgaris were included into this evaluation. This led to the exclusion of a number of substances which are traditionally used alone or in combination for the treatment of moderate or severe psoriasis vulgaris (e.g. dithranol, salicyc acid, tar, corticosteroids and topical retinoids). Moreover, other approaches which include neither drugs nor UV light are not discussed in this HTA although the authors believe in the importance of psychotherapeutical interventions, educational approaches and combined medical and non-medical approaches in rehabilitational medicine in the management of psoriasis vulgaris. The transferability of the health economic evaluations is strongly limited by the fact that all included health economic evaluations except one were not aligned to a German setting. A future research question will be the evaluation of the duration of remission and relapse ratios in the context of different therapy options of moderate and severe psoriasis. Moreover, the consideration of combined outcomes such as the improvement of psoriatic symptoms and the decrease of symptoms in accompanying psoriasis arthritis represents a future requirement of health assessment. Conclusions: From the clinical point of view it is positive that the spectrum of therapeutic procedures for a chronic severe skin disease has increased continuously during the last years. In cases of individual contraindications or individual inefficacies it is now possible to try alternative approaches. Moreover the risk of long-term side effects can be reduced by changing the therapeutical procedure after some time (so-called rotation therapy). The therapeutical algorithm for severe psoriasis vulgaris now includes photo(chemo-)therapy in combination with topical substances, oral fumaric acid esters, retinoids (in combination with phototherapy or topical substances), methotrexate, cylosporine and the new biologics. Future studies should address therapeutical approaches which can not easily be studied by RCT, e.g. physical, balneological, climate approaches, educational programs and complex rehabilitation therapy which all may have positive effects on individuals with severe psoriasis. As in medical therapy management of moderate and severe psoriasis the economic evaluation also points out the way of a strategic therapy concept which corresponds to a large extent to the algorithm in medical practice

Recurrent eczema herpeticum – a retrospective European multicenter study evaluating the clinical characteristics of eczema herpeticum cases in atopic dermatitis patients

Background Eczema herpeticum (EH ) is a disseminated viral infection of eczematous skin disease with the herpes simplex virus. Knowledge on clinical characteristics, risk factors and recurrent disease is limited. Our aim was to better define clinical characteristics and risk factors for EH and especially for recurrent EH . Methods A retrospective analysis of EH cases assessed the history, clinical signs, prior treatment and laboratory results using a predefined questionnaire. Results A total of 224 EH cases from eight European centres were included. Extrinsic AD was identified as risk factor for EH , and only one patient suffered from intrinsic AD . Early onset of AD was identified as risk factor for recurrent EH . Pretreatment with topical steroids, systemic steroids, topical calcineurin inhibitors or plain emollients reflected standard therapy. Many patients showed AD lesions without EH , but skin without AD lesions was never affected by herpetic lesions. Conclusion Patients with clinically active, extrinsic AD are at risk of EH . Recurrent EH is associated with confounders of severe atopic distortion and requires active AD lesions for clinical manifestation. Recurrent eczema herpeticum mainly affects patients with early onset of AD

The epidemiology of food allergy in Europe: protocol for a systematic review

BackgroundThe European Academy of Allergy and Clinical Immunology is in the process of developing its Guideline for Food Allergy and Anaphylaxis, and this protocol of a systematic review is one of seven inter-linked evidence syntheses that are being undertaken in order to provide a state-of-the-art synopsis of the current evidence base in relation to epidemiology, prevention, diagnosis and clinical management and impact on quality of life, which will be used to inform the formulation of clinical recommendations.The aims of the systematic review will be to understand and describe the epidemiology of food allergy, i.e. frequency, risk factors and outcomes of patients suffering from food allergy, and to describe how these characteristics vary by person, place and time.MethodsA highly sensitive search strategy has been developed to retrieve articles that have investigated the various aspects of the epidemiology of food allergy. The search will be implemented by combining the concepts of food allergy and its epidemiology from electronic bibliographic databases.DiscussionThis systematic review will provide the most up to date estimates of the frequency of food allergy in Europe. We will attempt to break these down by age and geographical region in Europe. Our analysis will take into account the suitability of the study design and the respective study biases that could affect exposure and outcome. We will examine the different methods to diagnose food allergy and the associated measures of occurrence