Subcutaneous immunotherapy with a depigmented polymerized birch pollen extract--a new therapeutic option for patients with atopic dermatitis

[Allergen immunotherapy for atopic dermatitis]

Seit dem ersten Bericht über die Allergenimmuntherapie (AIT) durch Noon et al. vor 110 Jahren wurden zahlreiche klinische und grundlagenwissenschaftliche Studien durchgeführt, um die Effekte der einzigen kurativen Behandlung von Allergien zu untersuchen. Bei der atopischen Dermatitis (AD) findet sie jedoch nur selten Anwendung, obwohl es Evidenz dafür gibt, dass Aeroallergene zu Exazerbationen der Erkrankung beitragen können. Dieser Übersichtsbeitrag umfasst die aktuelle Studienlage, Metaanalysen und Leitlinienempfehlungen zur AIT bei AD-Patienten. Es zeigt sich eine große Heterogenität hinsichtlich Studiendesigns, Patientenkohorten, Allergenen, Applikationsformen und Endpunkten, wodurch die Vergleichbarkeit der Studien erschwert wird. Mehrere Untersuchungen zeigen eine positive Wirkung der AIT auf den Schweregrad der AD, was darauf hindeutet, dass zumindest eine Untergruppe von Patienten von der Behandlung profitieren kann. Weitere Entwicklungen auf dem Gebiet der AIT könnten dazu beitragen, dass die Therapie einen breiteren Einsatz bei AD-Patienten findet.

Improvement of clinical and immunological parameters after allergen-specific immunotherapy in atopic dermatitis

BACKGROUND

Allergen immunotherapy (AIT) is considered a curative treatment in some atopic diseases, but in AD contradictory clinical results exist and the action of AIT has not been elucidated. In the literature, there is no evidence for parallel investigations of permeability barrier, cutaneous and blood immune responses after AIT in AD.

OBJECTIVES

The objective was to investigate immune parameters in the blood and skin and to detect clinical and barrier changes after AIT in AD.

METHODS

Mild-to-moderate AD patients (n = 14) with concomitant allergic rhinitis to house dust mites were selected. All patients received topical treatment, while eight patients were randomly selected for adjuvant AIT also. At baseline and after 6 months, clinical, barrier and immunological investigations (serum and skin tests) were performed. In selected patients, biopsies from atopy patch tests (APTs) were analysed by immunohistochemistry for AD-relevant immune cells and mediators.

RESULTS

In the adjuvant AIT group, clinical parameters and barrier functions improved significantly. Blood immune parameters displayed no significant changes. Post-AIT APT became negative in all patients in the AIT group, but remained positive in the non-AIT group. Cutaneous dendritic cell and T-cell recruitment decreased significantly after allergen challenge in the AIT group, but no significant changes in skin or serum immunoglobulin E levels or prick test (SPT) reactivity were detected.

CONCLUSIONS

Allergen immunotherapy is a beneficial adjuvant treatment for sensitized AD patients. AIT improves not only clinical symptoms, but also permeability barrier functions. The effect of AIT on sensitization should be detected by APT, not by SPT.

Molecular aspects of allergens in atopic dermatitis

PURPOSE OF REVIEW

Molecular allergology uses pure, mainly recombinant and structurally defined allergen molecules and allergen-derived epitopes to study mechanisms of IgE-associated allergy, to diagnose, and even predict the development of allergic manifestations and to treat and prevent IgE-associated allergies. Atopic dermatitis, a chronic inflammatory skin disease is almost always associated with IgE sensitization to allergens. However, also non-IgE-mediated pathomechanisms seem to be operative in atopic dermatitis and it is often difficult to identify the disease-causing allergens. Here we review recent work showing the usefulness of molecular allergology to study mechanisms of atopic dermatitis, for diagnosis and eventually for treatment and prevention of atopic dermatitis.

RECENT FINDINGS

IgE sensitization to airborne, food-derived, microbial allergens, and autoallergens has been found to be associated with atopic dermatitis. Using defined allergen molecules and non-IgE-reactive allergen derivatives, evidence could be provided for the existence of IgE- and non-IgE-mediated mechanisms of inflammation in atopic dermatitis. Furthermore, effects of epicutaneous allergen administration on systemic allergen-specific immune responses have been studied. Multi-allergen tests containing micro-arrayed allergen molecules have been shown to be useful for the identification of culprit allergens in atopic dermatitis and may improve the management of atopic dermatitis by allergen-specific immunotherapy, allergen avoidance, and IgE-targeting therapies in a personalized medicine approach.

SUMMARY

Molecular allergology allows for dissection of the pathomechanisms of atopic dermatitis, provides new forms of allergy diagnosis for identification of disease-causing allergens, and opens the door to new forms of management by allergen-specific and T cells-targeting or IgE-targeting interventions in a personalized medicine approach.

Allergen immunotherapy in atopic dermatitis

INTRODUCTION

Atopic dermatitis (AD) is a chronic relapsing skin disease, characterized by flare-up due to the exposure to allergens in patients sensitized to them. Currently, therapy of AD is mainly based on symptomatic treatment and avoidance of irritating/allergenic factors, house dust mites being particularly important. Allergen immunotherapy (AIT) is suggested to be the only etiologic treatment, to modify the natural history of the disease. Areas covered: The aim of this review is investigating the putative role of AIT in AD through the evaluation of the most recent scientific literature. Several studies have been conducted since 1970, with promising results in improving the clinical outcome of AD, but they often lack the necessary scientific rigorousness. Moreover, heterogeneity of the studies makes it very difficult to compare and to analyze data in a systematic review or meta-analysis. Expert commentary: As a result of the above-mentioned limitations, the treatment of AD with causative aeroallergen can nowadays be suggested only as an add-on therapy in selected patients who are non-responsive to the traditional therapy.

Debates in allergy medicine: specific immunotherapy efficiency in children with atopic dermatitis

Allergen specific immunotherapy (AIT) has been the only pathogenetically relevant treatment of IgE-mediated allergic diseases (ADs) for many years. The use of AIT for atopic dermatitis (AD) treatment is dubious and has both followers and opponents. The improvement of subcutaneous AIT (SCIT) and introduction of Sublingual immunotherapy (SLIT) gives prospects of their application both for adults and children suffering from AD. This review presents results of scientific research, system and meta-analyses that confirm the clinical efficacy of AIT for children with AD who has the sensitization to allergens of house dust mite, grass and plant pollen suffering from co-occurring respiratory ADs and with moderate and severe course of allergic AD. There have been analyzed the most advanced achievements in AIT studies as well as there have been specified the unmet needs in AD. The preliminary diagnostics of IgE-mediated AD and pathophysiological disorders, including immune ones, will allow a doctor to develop appropriate comprehensive treatment algorithm for children's AD aimed at its correction. The including of AIT to the children's comprehensive therapy program is reasonable only if AD has the allergic form. It is necessary better to design the randomized research studies and to acquire extended clinical practice in children with AD. Use of the successes of molecular-based allergy diagnostics will help to optimize and personalize the process of selecting the necessary allergens to determine the most appropriate vaccines for children considering the results of the allergen component diagnostics. The strategy of treatment of children with AD in future will be based on individual target therapy.

Advances in the diagnosis and therapeutic management of atopic dermatitis

Atopic dermatitis is a very prevalent disease that affects children as well as adults. The disease has a severe impact on quality of life for the patients and their families. The skin in atopic dermatitis patients is a site of both a severe inflammatory reaction dominated by lymphocytes and decreased skin barrier function. The treatment of the disease is mainly aimed at reducing the inflammation in the skin and/or restoring the skin barrier function. However, most of the treatments used today singularly aim at reducing the inflammation in the skin. Depending on the severity of the disease, the anti-inflammatory treatment may be topical or systemic, but basic treatment, no matter the severity, should always be emollients. In addition, new studies have shown good effects of psychosocial interventions, such as eczema schools, for patients and their families. This review covers the latest trends in the treatment of atopic dermatitis.

Systemic therapy for atopic dermatitis

Systemic therapy for atopic dermatitis (AD) is indicated in patients with severe disease refractory to adequate topical treatment. Currently available drugs aim to decrease inflammation by suppressing and/or modulating immune responses and thus may indirectly improve skin barrier function, resulting in a decrease in clinical signs and symptoms in particular pruritus. Before considering systemic treatment, patient adherence to topical treatment including skin care has to be ensured. The selection of the drug depends on the disease severity, localization, complications, concomitant diseases, and age of the patient, but also on their availability and costs as well as the doctor's experience. Bearing in mind the potential risk of resistance, systemic therapy with antibiotics should be exclusively considered in clinically manifest infections such as in children. Here, we review recently published clinical trials and case reports on systemic therapy of pediatric and adult patients with AD to draw conclusions for clinical practice. Although AD is a common disease, controlled clinical studies investigating the efficacy of systemic drugs are scarce, except for cyclosporine, which has been approved for the therapy of severe AD.

Depigmented allergoids reveal new epitopes with capacity to induce IgG blocking antibodies

Background. The synthesis of allergen-specific blocking IgGs that interact with IgE after allergen immunotherapy (SIT) has been related to clinical efficacy. The objectives were to investigate the epitope specificity of IgG-antibodies induced by depigmented-polymerized (Dpg-Pol) allergoids and unmodified allergen extracts, and examine IgE-blocking activity of induced IgG-antibodies. Methods. Rabbits were immunized with native and Dpg-Pol extracts of birch pollen, and serum samples were obtained. Recognition of linear IgG-epitopes of Bet v 1 and Bet v 2 and the capacity of these IgG-antibodies to block binding of human-IgE was determined. Results. Serum from rabbits immunized with native extracts recognised 11 linear epitopes from Bet v 1, while that from Dpg-Pol-immunized animals recognised 8. For Bet v 2, 8 epitopes were recognized by IgG from native immunized animals, and 9 from Dpg-Pol immunized one. Dpg-Pol and native immunized serum did not always recognise the same epitopes, but specific-IgG from both could block human-IgE binding sites for native extract. Conclusions. Depigmented-polymerized birch extract stimulates the synthesis of specific IgG-antibodies which recognize common but also novel epitopes compared with native extracts. IgG-antibodies induced by Dpg-Pol effectively inhibit human-IgE binding to allergens which may be part of the mechanism of action of SIT.

Evaluation of the adult patient with atopic dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin disease with a large impact on quality of life of the patients and their families. In most cases, the diagnosis of AD can easily be made based on (family) history and clinical examination. If necessary, a practical set of diagnostic criteria such as the UK diagnostic criteria can be used. During the diagnostic phase, it is important to pay attention to atopic comorbidity, such as allergic airway disease (allergic asthma and/or rhinitis), allergic eye disease (atopic (kerato) conjunctivitis) and immediate-type food allergy. This will not have direct consequences for the treatment of AD, but may be important for the overall well-being of the patient. Psychological factors, such as family circumstances, work/school performance and lifestyle factors should also be explored. Severity scoring using properly validated scoring lists may not be necessary for the diagnosis, however, is recommended for monitoring therapy. Simple scoring systems, such as TIS and IGA are easy to perform in daily practice. Several flare factors in AD, such as exposure to irritants or UV light, can be identified by history and clinical examination: in individual cases, additional diagnostic tests may sometimes be useful to confirm clinical suspicion. There is only limited evidence that allergen exposure to aeroallergens and/or food allergens influences AD severity. Therefore, routine allergen testing is not necessary for diagnosis and treatment of AD. The decision to perform allergen tests mainly depends on atopic comorbidity.

New directions in immunotherapy

Allergen immunotherapy (AIT) is effective in reducing the clinical symptoms associated with allergic rhinitis, asthma and venom-induced anaphylaxis. Subcutaneous (SCIT) and sublingual immunotherapy (SLIT) with unmodified allergen extracts are the most widely prescribed AIT regimens. The efficacy of these 2 routes appears comparable, but the safety profile with SLIT is more favorable allowing for home administration and requiring less patient time. However, both require that the treatment is taken regularly over several years, e.g., monthly in a supervised medical setting with SCIT and daily at home with SLIT. Despite the difference in treatment settings, poor adherence has been reported with both routes. Emerging evidence suggests that AIT may be effective in other allergic conditions such as atopic dermatitis, venom sting-induced large local reactions, and food allergy. Research with oral immunotherapy (OIT) for food allergies suggest that many patients can be desensitized during treatment, but questions remain about whether this can produce long term tolerance. Further studies are needed to identify appropriate patients and treatment regimens with these conditions. Efforts to develop safer and more effective AIT for inhalant allergies have led to investigations with modified allergens and alternate routes. Intralymphatic (ILIT) has been shown to produce long-lasting clinical benefits after three injections comparable to a 3-year course of SCIT. Epicutaneous (EPIT) has demonstrated promising results for food and inhalant allergies. Vaccine modifications, such as T cell epitopes or the use of viral-like particles as an adjuvant, have been shown to provide sustained clinical benefits after a relatively short course of treatment compared to the currently available AIT treatments, SLIT and SCIT. These newer approaches may increase the utilization and adherence to AIT because the multi-year treatment requirement of currently available AIT is a likely deterrent for initiating and adhering to treatment.

Immunotherapies in dermatologic disorders

Treatment modalities and therapeutic response experience support the use of immunotherapy in the treatment of many diseases in all fields of medicine. The aim of this article is to conduct and present a review of literature on the use of immunotherapy in the treatment of skin diseases analyzing scientific literature available up to January 2012. Studies that presented evidence-based data were selected. The article discusses how blocking or reverting the effect of a specific immunologic disequilibrium can treat dermatoses and intends to transfer a large amount of immunotherapy knowledge into a historical perspective for physicians naive to immunotherapy practices.

[Indications and evidence base for specific immunotherapy in childhood]

Allergic rhinitis (AR) is a common disease affecting 7-17% of children and adolescents who may suffer from a significantly impaired quality of life. For 100 years subcutaneous immunotherapy (SCIT) has been used to treat AR. If patients are chosen carefully, a clinically relevant reduction of seasonal symptoms and medication use can be achieved by SCIT. Serious adverse events are rarely encountered during adequately performed and monitored SCIT. Sublingual immunotherapy (SLIT) may be used as a less painful therapeutic alternative in children if the administration of SCIT is impossible. Recent controlled trials have shown that SLIT performed over one pollen season also ameliorates seasonal symptoms and reduces the need for concomitant medication. Local reactions are frequently encountered during SLIT whereas systemic and life-threatening adverse events under correctly performed SLIT have not been reported so far.

Atopic dermatitis and allergic rhinitis--do co-effects in therapy exist?

Atopic dermatitis and allergic rhinitis frequently appear together in the same patients. The pathogenesis of both disorders is complex and still incompletely understood. Nevertheless, pathophysiological overlaps suggest the existence of potential therapeutic co-effects. While data pointing towards a positive effect of allergen elimination for both diseases is still limited, there is now increasing evidence showing beneficial effects of specific immunotherapy in patients suffering from atopic dermatitis and additional type I allergies. H(1)-antihistamines were also found to exert moderate positive effects on the symptoms of atopic dermatitis in single studies. In summary, a limited therapeutic co-effect of the above mentioned treatment options can be expected in case of the parallel existence of atopic dermatitis and allergic rhinitis in the same patient. More studies on this issue during the next years are desirable. In addition, a better understanding of the pathophysiology should have a positive impact on the treatment of atopic manifestations such as atopic dermatitis and allergic rhinitis.

Atopic dermatitis - from new pathophysiologic insights to individualized therapy

Recently, important novel insights into the complex pathophysiology of atopic dermatitis (AD) have been gained. However, in most cases the therapy of AD is limited to base line therapy with emollients combined with symptomatic, rather general immunosuppressive treatment approaches of the flare-ups. Latest research findings together with experiences from daily clinical practice, which support the concept that a combination of general disease features together with specific trigger factors in the individual patients drive the disease, might be helpful for a subclassification of patients with AD based on the most relevant pathophysiologic modifications. Subclassification of patients with AD seems indispensable to introduce rationale-based, individualized treatment approaches of AD, which target specific modified pathways. In this review, we provide an overview about a selection of pathophysiologic pathways, which hold promise to represent targets of such therapeutic approaches in the near future.