Differences in clinical and immunologic reactivity of patients allergic to grass pollens and to multiple-pollen species. II. Efficacy of a double-blind, placebo-controlled, specific immunotherapy with standardized extracts

Mepolizumab induced palmoplantar psoriasis: A case report

BACKGROUND

Atopic dermatitis and asthma are two diseases whose pathogenesis is largely attributable to the activation, at least in the initial stages, of T helper (Th)-2 Lymphocytes, the related cytokine axis, and B lymphocytes with antibody production. Psoriasis is conversely a pathology resulting from a recruitment of Th-17 and Th-1 lymphocytes, after an initial role of innate immunity. Mepolizumab is a humanized monoclonal antibody directed against interleukin (IL)-5, a central cytokine in the Th-2 axis, therefore involved in the pathogenesis of asthma. Several authors have described the appearance of psoriatic lesions in patients with asthma or atopic dermatitis following the therapy with dupilumab, a monoclonal antibody that blocks the interleukin (IL)-4, another Th-2 cytokine.

CASE SUMMARY

We present the case of a 59-year-old patient who developed psoriasiform lesions on the palms after mepolizumab therapy for asthma, for the activation of the parallel cytokine cascade after the blockade of IL-5. We successfully treated the patient with a topical calcipotriol and betamethasone ointment.

CONCLUSION

We should investigate with further attention the possible impact on the human immunological ecosystem put in place by the inhibition of the activity of individual inflammatory mediators, so as to be able to recognize the initial adverse effects early.

To mix or not to mix in allergy immunotherapy vaccines

PURPOSE OF REVIEW

European and US allergists generally do not agree on the approach to subcutaneous allergy immunotherapy in patients with multiple allergies. The North American approach is to treat with a mixture that contains all the allergen extracts to which the patient has evident clinical sensitivity, whereas the European approach is to select for treatment the one or at the most two allergens that are clinically most important for the patient.

RECENT FINDINGS

Recent society guidelines continue to recommend these differing practices of treating the polyallergic patient and reviews of prescribing practices indicate these divergent recommendations are followed in Europe and the USA.

SUMMARY

The objections by European allergists to the practice by US allergists are that multiallergen immunotherapy leads to dilution of allergens to less than effective doses, that proteases in some extracts can degrade allergens in other extracts, that there is a problem of safety and inability to determine which component extract caused a systemic reaction, and finally that there is alack of convincing studies demonstrating efficacy of multiallergen mixtures. Each of these contentions is addressed.

Tropomyosin in mugwort cross-reacts to house dust mite, eliciting non-Th2 response in allergic rhinitis patients sensitized to house dust mite

Background

Mugwort and house dust mite (HDM) are two of the most common inhalant allergens in Asia, however, whether mugwort affects polysensitized HDM⁺ allergic rhinitis (AR) patients has not been elucidated.

Methods

Overall, 15,884 AR outpatients were assessed for clinical status. Amino acid sequences of mugwort were determined by mass spectrometry. Afterward, cross-reactivity between mugwort tropomyosin and Dermatophagoides pteronyssinus 10 (Der p10) was analysed by ELISA inhibition and basophil activation experiments. To compare immunologic responses eliciting by two different tropomyosins, peripheral blood mononuclear cells (PBMCs) of HDM-monosensitized patients were stimulated by mugwort, HDM, Der p10 and synthetic peptides representing mugwort tropomyosin respectively.

Results

Polysensitized HDM⁺AR patients were mainly sensitized to cat and mugwort, and the positive rate of monosensitized HDM⁺AR out-clinic patients was increased during the mugwort pollen season. Tropomyosin protein was able to find in mugwort. Synthetic tropomyosin peptide of mugwort activated basophils which were primed by HDM-specific IgE; ELISA inhibition experiment showed synthetic tropomyosin peptide of mugwort inhibited IgE binding to HDM tropomyosin, Der p10. Unlike HDM and Derp 10, mugwort and mugwort tropomyosin mainly induced IFN-γ and IL-17 release in PBMCs of monosensitized HDM⁺AR patients, but not IL-5.

Conclusions

Pan-allergen tropomyosin accounts for the cross-reactivity between mugwort and HDM, which reminds HDM⁺ patients to reduce mugwort exposure in mugwort pollen season in virtue of the tropomyosin induced mild inflammation.

Supplementary information

The online version contains supplementary material available at 10.1186/s12948-021-00142-z.

Planning and approach to allergen-specific immunotherapy in polyallergic patients

Allergy immunotherapy (AIT) is currently the only disease-modifying treatment for allergic-respiratory diseases. Polysensitization may increase the severity of current disease resulting in subsequent asthma development in patients with allergic rhinitis. Due to the absence of general recommendations for the practical approach to polysensitized patients, clinical management is not standardized. The correlation between sensitizations and clinical symptoms, elimination of possible pollen cross-reactivities and principles of homologous allergen groups will guide the allergists to deduce the most relevant allergens for AIT. In the highlight of the previously proposed approach strategies to polyallergic patients, hereby we propose a revised practical stepwise approach based on the current European Medicine Agency (EMA) guidelines. However, more supporting data from well-designed, controlled, future studies are needed to improve clinical management recommendations for AIT in polyallergic patients.

Prospective comparison of a nonmodified and a modified mite extract for immunotherapy in children and adolescents

Aim: This prospective study compares nonmodified and modified house dust mite extracts for allergen immunotherapy (AIT) in pediatric patients with allergic asthma. Materials & methods: Total 95 patients underwent bronchial allergen provocation (BAP). AIT was recommended to 62 patients. Complete datasets of 54 subjects were obtained. Primary aim was the comparison of treatment success defined by BAP between two extracts after 1 year. Secondary parameters were laboratory parameters and clinical symptoms. Results: Significant improvement (p < 0.001) was measured by BAP in both treatment groups. No change was seen in the controls. Both extracts exerted comparable effects on all parameters. Conclusion: After 1 year of AIT, the extracts were equally efficient, with significant improvements in 70.0% (nonmodified) and 72.2% (modified) of patients.

Allergen immunotherapy for allergic rhinoconjunctivitis: A systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis. To inform the development of clinical recommendations, we undertook a systematic review to assess the effectiveness, cost-effectiveness, and safety of AIT in the management of allergic rhinoconjunctivitis.

METHODS

We searched nine international biomedical databases for published, in-progress, and unpublished evidence. Studies were independently screened by two reviewers against predefined eligibility criteria and critically appraised using established instruments. Our primary outcomes of interest were symptom, medication, and combined symptom and medication scores. Secondary outcomes of interest included cost-effectiveness and safety. Data were descriptively summarized and then quantitatively synthesized using random-effects meta-analyses.

RESULTS

We identified 5960 studies of which 160 studies satisfied our eligibility criteria. There was a substantial body of evidence demonstrating significant reductions in standardized mean differences (SMD) of symptom (SMD -0.53, 95% CI -0.63, -0.42), medication (SMD -0.37, 95% CI -0.49, -0.26), and combined symptom and medication (SMD -0.49, 95% CI -0.69, -0.30) scores while on treatment that were robust to prespecified sensitivity analyses. There was in comparison a more modest body of evidence on effectiveness post-discontinuation of AIT, suggesting a benefit in relation to symptom scores.

CONCLUSIONS

AIT is effective in improving symptom, medication, and combined symptom and medication scores in patients with allergic rhinoconjunctivitis while on treatment, and there is some evidence suggesting that these benefits are maintained in relation to symptom scores after discontinuation of therapy.

Association of Polysensitization, Allergic Multimorbidity, and Allergy Severity: A Cross-Sectional Study of School Children

BACKGROUND

Aeroallergen sensitization is related to the coexistence of allergic diseases, but the nature of this relationship is poorly understood. The aim of this study was to clarify the relationship of polysensitization with allergic multimorbidities and the severity of allergic diseases.

METHODS

This study is a cross-sectional analysis of 3,368 Korean children aged 6-7 years-old. We defined IgE-mediated allergic diseases based on structured questionnaires, and classified the sensitivity to 18 aeroallergens by logistic regression and the Ward hierarchical clustering method. The relationship of polysensitization (positive IgE responses against 2 or more aeroallergens classes) with allergic multimorbidities (coexistence of 2 or more of the following allergic diseases: asthma, rhinitis, eczema, and conjunctivitis) and severity of allergic diseases was determined by ordinal logistic regression analysis.

RESULTS

The rate of polysensitization was 13.6% (n = 458, 95% CI 12.4-14.8) and that of allergic multimorbidity was 23.5% (n = 790, 95% CI 22.0-24.9). Children sensitized to more aeroallergens tended to have more allergic diseases (rho = 0.248, p < 0.001), although the agreement between polysensitization and multimorbidity was poor (kappa = 0.11, p < 0.001). The number allergen classes to which a child was sensitized increased the risk of wheezing attacks (1 allergen: adjusted odds ratio [aOR] 2.22, 4 or more allergens: aOR 9.39), absence from school (1 allergen: aOR 1.96, 3 allergens: aOR 2.08), and severity of nasal symptoms (1 allergen: aOR 1.61, 4 or more allergens: aOR 4.38).

CONCLUSION

Polysensitization was weakly related to multimorbidity. However, the number of allergens to which a child is sensitized is related to the severity of IgE-mediated symptoms.

Paving the way of systems biology and precision medicine in allergic diseases: the MeDALL success story: Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015

MeDALL (Mechanisms of the Development of ALLergy; EU FP7-CP-IP; Project No: 261357; 2010-2015) has proposed an innovative approach to develop early indicators for the prediction, diagnosis, prevention and targets for therapy. MeDALL has linked epidemiological, clinical and basic research using a stepwise, large-scale and integrative approach: MeDALL data of precisely phenotyped children followed in 14 birth cohorts spread across Europe were combined with systems biology (omics, IgE measurement using microarrays) and environmental data. Multimorbidity in the same child is more common than expected by chance alone, suggesting that these diseases share causal mechanisms irrespective of IgE sensitization. IgE sensitization should be considered differently in monosensitized and polysensitized individuals. Allergic multimorbidities and IgE polysensitization are often associated with the persistence or severity of allergic diseases. Environmental exposures are relevant for the development of allergy-related diseases. To complement the population-based studies in children, MeDALL included mechanistic experimental animal studies and in vitro studies in humans. The integration of multimorbidities and polysensitization has resulted in a new classification framework of allergic diseases that could help to improve the understanding of genetic and epigenetic mechanisms of allergy as well as to better manage allergic diseases. Ethics and gender were considered. MeDALL has deployed translational activities within the EU agenda.

Allergen immunotherapy (AIT) for the multiple-pollen sensitive patient

INTRODUCTION

The majority of allergic subjects are polysensitized. In Europe, allergy immunotherapy (AIT) in these patients is usually limited to their single clinically most troublesome allergy while in the U.S. the immunotherapy prescription usually includes all allergen extracts to which the patient has evidence of clinical sensitivity. Areas covered: This article will review the evidence supporting the U.S. practice. It will also review the major new development in the management of polysensitized patients, the introduction of component-resolved diagnosis (CRD). Expert commentary: This allows, in many cases, distinguishing in polysensitized patients between sensitization to the major allergens of several unrelated allergen extracts and to panallergens that cause broad patterns of cross-reactivity.

Subcutaneous Immunotherapy and Sublingual Immunotherapy: Comparative Efficacy, Current and Potential Indications, and Warnings--United States Versus Europe

Subcutaneous immunotherapy and sublingual immunotherapy are effective for allergic rhinitis and allergic asthma and with some support for use in selected patients with atopic dermatitis. The sequence of immunologic responses is the same, irrespective of the route of administration, and similar disease modification has been demonstrated. However, there are differences between the two approaches. The most important is the greatly reduced likelihood of sublingual immunotherapy producing systemic reactions. There are major drawbacks for sublingual immunotherapy in regard to dosing. Finally, there is the question of relative clinical efficacy, with the currently available data favoring subcutaneous immunotherapy.

Effect on quality of life of the mixed house dust mite/weed pollen extract immunotherapy

BACKGROUND

Although many patients with allergic rhinitis have symptoms due to sensitization to more than one kind of allergens, and mixed allergen extracts are widely used for immunotherapy, there are few published trials.

OBJECTIVE

Our study aimed to evaluate the effect of multiple-allergen immunotherapy on improving the symptoms and quality of life of allergic rhinitis patients.

METHODS

We performed a 1-year single-center observation study of subcutaneous immunotherapy using house dust mite extract (n = 12), weed pollen extract (n = 21), or mixed house dust mite/weed pollen extract (n = 11) in 44 allergic rhinitis patients. All the allergens responsible for the symptom of each patient were included in his immunotherapy. Symptom score, medication score, and quality of life of the patients were evaluated before and after 1-year immunotherapy. Quality of life was evaluated with the Rhinoconjunctivitis Quality of Life Questionnaire.

RESULTS

In all 3 groups receiving subcutaneous immunotherapy, significant improvement of symptom score, medication score, and quality of life was found vs. baseline at 1 year, irrespective of the allergen used. In the weed pollen season, the changes of quality of life questionnaire score after 1-year treatment were not significantly different between the weed pollen group (1.55 ± 1.24) and the mixed house dust mite/weed pollen group (1.14 ± 1.01). The same happened in the nonpollen seasons, during which dust mite immunotherapy (1.23 ± 1.63) and mixed immunotherapy (0.60 ± 0.47) did not show significantly different effect on the quality of life.

CONCLUSION

The multiple-allergen immunotherapy might be effective in polysensitized allergic rhinitis patients, and could improve their quality of life. Our result did not show significant difference between the effects of multiple-allergen immunotherapy and mono-allergen immunotherapy.

Immunologic alterations and efficacy of subcutaneous immunotherapy with Dermatophagoides pteronyssinus in monosensitized and polysensitized patients

BACKGROUND

There is a continuing debate about whether monoallergen subcutaneous immunotherapy (SCIT) is able to modulate immune and clinical responses toward main causal allergen in polysensitized patients.

OBJECTIVE

To investigate short-term immunologic changes and clinical effectiveness of SCIT with Dermatophagoides pteronyssinus in monosensitized and polysensitized patients who have rhinitis with or without asthma.

METHODS

Nineteen monosensitized and 24 polysensitized patients participated in this prospective, self-placebo-controlled, interventional study. Cluster immunotherapy with D pteronyssinus was administered after 2 months of placebo in both groups. Immunologic parameters, including CD203c expression on basophils after allergen stimulation, total IgE, specific IgE, and specific IgG4, were evaluated at baseline, after placebo, and after immunotherapy. Clinical effectiveness was assessed using monthly symptom-medication scores, visual analog scale, quality-of-life questionnaire, and nasal allergen provocation test.

RESULTS

At baseline, polysensitized patients had higher CD203c expression on basophils than monosensitized patients (P = .007). Activated basophils expressing CD203c, total IgE, and specific IgG4 were significantly increased after immunotherapy compared with baseline and placebo in the polysensitized group (P < .025). After immunotherapy, specific IgE and D pteronyssinus-induced CD203c expression were significantly higher in polysensitized than monosensitized patients (P < .05). The total symptom scores and the Mini Rhinoconjunctivitis Quality of Life Questionnaire scores in polysensitized patients and the visual analog scale scores in both groups were lower after immunotherapy compared with baseline and placebo (P < .025). Titrated nasal allergen provocation test with D pteronyssinus increased after immunotherapy in the monosensitized group (P < .05).

CONCLUSION

This study indicates that monosensitized and polysensitized patients have distinct humoral response and basophil behavior to SCIT. However, a single-allergen immunotherapy corresponding to the most clinically troublesome allergy in polysensitized patients can lead to early clinical efficacy comparable to that seen in monosensitized patients.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01795846.

Are allergic multimorbidities and IgE polysensitization associated with the persistence or re-occurrence of foetal type 2 signalling? The MeDALL hypothesis

Allergic diseases [asthma, rhinitis and atopic dermatitis (AD)] are complex. They are associated with allergen-specific IgE and nonallergic mechanisms that may coexist in the same patient. In addition, these diseases tend to cluster and patients present concomitant or consecutive diseases (multimorbidity). IgE sensitization should be considered as a quantitative trait. Important clinical and immunological differences exist between mono- and polysensitized subjects. Multimorbidities of allergic diseases share common causal mechanisms that are only partly IgE-mediated. Persistence of allergic diseases over time is associated with multimorbidity and/or IgE polysensitization. The importance of the family history of allergy may decrease with age. This review puts forward the hypothesis that allergic multimorbidities and IgE polysensitization are associated and related to the persistence or re-occurrence of foetal type 2 signalling. Asthma, rhinitis and AD are manifestations of a common systemic immune imbalance (mesodermal origin) with specific patterns of remodelling (ectodermal or endodermal origin). This study proposes a new classification of IgE-mediated allergic diseases that allows the definition of novel phenotypes to (i) better understand genetic and epigenetic mechanisms, (ii) better stratify allergic preschool children for prognosis and (iii) propose novel strategies of treatment and prevention.

Allergen-specific immunotherapy in asthmatic children: from the basis to clinical applications

Atopic asthma in childhood with the tendency to persist into adult life is an important issue in pediatrics. Allergen-specific immunotherapy (SIT) is the only curative treatment option for these children, being directed to the causes of the disease. The Th2 phenotype is a predominant immunological pattern in atopic asthma and SIT leads to apoptosis/anergy of T cells and induces immune-regulatory responses and immune deviation towards Th1. Many factors can affect the safety and efficacy of SIT, such as pattern of sensitization, allergy vaccine (allergen extracts, adjuvants and conjugated molecules), route of administration (subcutaneous or sublingual) and different treatment schedules. Overall, asthma symptoms and medication scores usually decrease following a SIT course and the most common observed side effects are restricted to local swelling, erythema and pruritus. Compared with conventional pharmacotherapy, SIT may be more cost effective, providing a benefit after discontinuation and a steroid-sparing effect. In addition, it can prevent new sensitizations in monosensitized asthmatic children. Microbial supplements such as probiotics, immunomodulatory substances like anti-IgE/leukotrienes, antibodies and newer allergen preparations such as recombinant forms have been tested to improve the efficacy and safety of SIT with inconclusive results. In conclusion, SIT provides an appropriate solution for childhood asthma that should be employed more often in clinical practice. Further studies are awaited to improve current knowledge regarding the mechanisms behind SIT and determine the most appropriate materials and schedule of immunotherapy for children with asthma.

Accelerated immunotherapy schedules

Rush and cluster immunotherapy schedules are accelerated immunotherapy build-up schedules. A cluster immunotherapy schedule involves the patient receiving several allergen injections (generally 2-4) sequentially in a single day of treatment on nonconsecutive days. The maintenance dose is generally reached in 4-8 weeks. In rush immunotherapy protocols, higher doses are administered at 15- to 60-min intervals over a 1- to 3-day period until the maintenance dose is achieved. This review will serve as an update for accelerated immunotherapy schedules. The review will include recent investigations demonstrating the safety of cluster schedules in atopic dermatitis, pediatric patients, and inhalant allergen mixtures and an accelerated protocol utilizing an infusion pump for allergen delivery. There has also been further elucidation on the immunological changes which occur during accelerated immunotherapy. Finally, new studies analyzing systemic reaction risk factors are discussed.

Multiallergen-specific immunotherapy in polysensitized patients: where are we?

Allergen-specific immunotherapy administered by the subcutaneous route was introduced a century ago and has been shown to be effective in the management of allergic rhinitis and asthma. More recently, the sublingual administration of allergen extracts has become popular, especially in European countries, and has also demonstrated efficacy in respiratory allergic diseases. Both modes of allergen administration during immunotherapy have been shown not only to reduce symptoms and the need for medication, but also to prevent the development of additional sensitivities in monosensitized patients, as well as asthma development in patients with allergic rhinitis, with a long-lasting effect after the completion of several years of treatment. Almost all of the well-designed and double-blinded, placebo-controlled studies evaluated treatment with single-allergen extracts. Therefore, most meta-analyses published to date evaluated immunotherapy with single allergen or extracts containing several cross-reactive allergens. As a result, in general, multiallergen immunotherapy in polysensitized patients (mixture of noncross-reactive allergens) is not recommended owing to lack of evidence. Although some guidelines have recommended against the use of multiallergen mixtures, allergists commonly use mixtures to which the patient is sensitive with the rationale that effective immunotherapy should include all major sensitivities. Literature on this subject is scarce in spite of the widespread use worldwide. Here, this issue will be extensively discussed based on currently available literature and future perspectives will also be explored.

Effectiveness of subcutaneous immunotherapy for allergic rhinoconjunctivitis and asthma: a systematic review

OBJECTIVES/HYPOTHESIS

To systematically review the effectiveness and safety of subcutaneous immunotherapy (SCIT) for treatment of allergic rhinoconjunctivitis and asthma, using formulations currently approved in the United States.

STUDY DESIGN

We searched the following databases up to May 21, 2012: MEDLINE, Embase, LILACS, and the Cochrane Central Register of Controlled Trials.

METHODS

We included randomized controlled trials published in English comparing SCIT to placebo, pharmacotherapy, or other SCIT regimens that reported clinical outcomes of interest. Studies of adults or mixed age populations were included. Studies were excluded if the diagnosis of allergy and/or asthma was not confirmed with objective testing. Paired reviewers selected articles for inclusion and extracted data. We assessed the risk of bias for each study and graded the strength of evidence for each outcome as high, moderate, or low.

RESULTS

Sixty-one studies met our inclusion criteria. Majority of the studies (66%) evaluated single-allergen immunotherapy regimens. The literature provides high-grade evidence that SCIT reduces asthma symptoms, asthma medication usage, rhinitis/rhinoconjunctivitis symptoms, conjunctivitis symptoms, and rhinitis/rhinoconjunctivitis disease-specific quality of life in comparison to placebo or usual care. There is moderate evidence that SCIT decreases rhinitis/rhinoconjunctivitis medication usage. Respiratory reactions were the most common systemic reaction. There were few reports of anaphylaxis; no deaths were reported.

CONCLUSIONS

Generally moderate to strong evidence supports the effectiveness of SCIT for treatment of allergic rhinitis and asthma, particularly with single-allergen immunotherapy regimens. Adverse reactions to SCIT are common, but no deaths were reported in the included studies.

Prospects for a vaccine in allergic diseases and asthma

Allergen-specific immunotherapy is widely used to treat allergic diseases, and current research is now focusing on the development of therapeutic vaccines acting on the IgE immune response following allergen challenge. The IgE immune response is dependent on genetic and environmental factors; production of IgE results from complex interactions among B cells, T cells, mast cells, basophils,surface and adhesion molecules and various cytokines. New vaccination methods under investigation involve allergen-specific or nonspecific methodology. Allergen-specific methods currently being developed include allergoids, passive saturation of effector cells, plasmid DNA immunisation and antigen-antibody complexes. The mechanisms of immunotherapy using allergen-specific methods differ with the allergens and the route of immunisation used (parenteral, intranasal, sublingual, oral or bronchial). Many vaccines being developed at present comprise synthetic, recombinant or highly purified subunit antigens, which although they have increased safety may also be less immunogenic.It is hoped that the addition of adjuvants will overcome this drawback. Methods of increasing the dose of allergen while reducing the possibility of an anaphylactic reaction include the use of non-anaphylactic isoforms of the allergens, alteration of the tertiary structure of the allergens and construction of minimal allergen-derived T cell peptides. Nonspecific approaches include humanised anti-IgE antibodies,moderation of the T(H)2 cytokine network and antisense oligodeoxynucleotide therapy.

Multiple-allergen and single-allergen immunotherapy strategies in polysensitized patients: looking at the published evidence

In allergen immunotherapy there is debate as to whether polysensitized patients are best treated with many allergens simultaneously (chosen according to the sensitization profile, a predominantly North American approach) or a single allergen (chosen according to the most clinically problematic allergy, a predominantly European approach). In patients seeking treatment for moderate-to-severe respiratory allergies, polysensitization is more prevalent (range, 50% to 80%) than monosensitization in both the United States and Europe. Safe, effective, single-allergen preparations will most likely have been tested in polysensitized patients. In robust, large-scale clinical trials of grass pollen sublingual tablets, polysensitized patients benefited at least as much from allergen immunotherapy as monosensitized patients. A recent review of multiallergen immunotherapy concluded that simultaneous delivery of multiple unrelated allergens can be clinically effective but that there was a need for additional investigation of therapy with more than 2 allergen extracts (particularly in sublingual allergen immunotherapy). More work is also required to determine whether single-allergen and multiallergen immunotherapy protocols elicit distinct immune responses in monosensitized and polysensitized patients. Sublingual and subcutaneous multiallergen immunotherapy in polysensitized patients requires more supporting data to validate its efficacy in practice.

Subcutaneous injection immunotherapy for optimal effectiveness

Immunotherapy by the subcutaneous injection of increasing doses and then maintenance doses of extracts of inhalant allergens has been practiced for 100 years. Controlled clinical trials have established its efficacy in treating allergic rhinitis, asthma, and stinging insect sensitivity, and there are preliminary data to suggest a favorable response in some patients with atopic dermatitis. The response to subcutaneous injection immunotherapy is dose dependent. Disease-modifying actions include blocking development of new sensitivities in monosensitized patients, blocking progression to asthma in patients with allergic rhinitis, and persistence of treatment effects for up to 7 to 10 years after an initial course.

Injection allergen immunotherapy for asthma

BACKGROUND

Allergen specific immunotherapy has long been a controversial treatment for asthma. Although beneficial effects upon clinically relevant outcomes have been demonstrated in randomised controlled trials, there remains a risk of severe and sometimes fatal anaphylaxis. The recommendations of professional bodies have ranged from cautious acceptance to outright dismissal. With increasing interest in new allergen preparations and methods of delivery, we updated the systematic review of allergen specific immunotherapy for asthma.

OBJECTIVES

The objective of this review was to assess the effects of allergen specific immunotherapy for asthma.

SEARCH STRATEGY

We searched the Cochrane Airways Group Trials Register up to 2005, Dissertation Abstracts and Current Contents.

SELECTION CRITERIA

Randomised controlled trials using various forms of allergen specific immunotherapy to treat asthma and reporting at least one clinical outcome.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed eligibility of studies for inclusion. Two authors independently performed quality assessment of studies.

MAIN RESULTS

Eighty-eight trials were included (13 new trials). There were 42 trials of immunotherapy for house mite allergy; 27 pollen allergy trials; 10 animal dander allergy trials; two Cladosporium mould allergy, two latex and six trials looking at multiple allergens. Concealment of allocation was assessed as clearly adequate in only 16 of these trials. Significant heterogeneity was present in a number of comparisons. Overall, there was a significant reduction in asthma symptoms and medication, and improvement in bronchial hyper-reactivity following immunotherapy. There was a significant improvement in asthma symptom scores (standardised mean difference -0.59, 95% confidence interval -0.83 to -0.35) and it would have been necessary to treat three patients (95% CI 3 to 5) with immunotherapy to avoid one deterioration in asthma symptoms. Overall it would have been necessary to treat four patients (95% CI 3 to 6) with immunotherapy to avoid one requiring increased medication. Allergen immunotherapy significantly reduced allergen specific bronchial hyper-reactivity, with some reduction in non-specific bronchial hyper-reactivity as well. There was no consistent effect on lung function. If 16 patients were treated with immunotherapy, one would be expected to develop a local adverse reaction. If nine patients were treated with immunotherapy, one would be expected to develop a systemic reaction (of any severity).

AUTHORS' CONCLUSIONS

Immunotherapy reduces asthma symptoms and use of asthma medications and improves bronchial hyper-reactivity. One trial found that the size of the benefit is possibly comparable to inhaled steroids. The possibility of local or systemic adverse effects (such as anaphylaxis) must be considered.

Comparison of allergen immunotherapy practice patterns in the United States and Europe

OBJECTIVE

To discuss important differences and similarities in the allergen specific immunotherapy (SIT) treatment practices for aeroallergen sensitivity in the United States and Europe.

DATA SOURCES

Information on regulation and standardization in the United States and Europe was obtained from a Food and Drug Administration Allergenic Products Advisory Committee meeting, published literature, personal communications, and information obtained from the extract manufacturers.

STUDY SELECTION

Information from the published literature included articles known to the authors and acknowledged consultants, textbooks, and PubMed, with search terms dependent on the particular subtopic.

RESULTS

Key differences between Europe and the United States include allergen extract regulation, standardization, formulation, types of allergen extracts, routes of administration, and reimbursement. Most SIT is formulated in US allergists' offices, whereas virtually all SIT is formulated by extract manufacturers in Europe. Sublingual immunotherapy represents a significant percentage of SIT treatment in Europe (approximately 45%), but only a small percentage of US allergists (approximately 5.9%) prescribe sublingual immunotherapy. Similarities between European and US allergist specialists lie in their perception of SIT and approach to providing optimal SIT care, which is detailed in their practice guidelines.

CONCLUSION

Significant differences and similarities exist in SIT practice patterns of US and European allergy specialists. The differences lie primarily in the availability of allergen extracts and how these extracts are formulated. A key similarity is that both recognize the need for ongoing research focused on developing safer and more effective SIT.

Clinical efficacy of house dust mite-specific immunotherapy in asthmatic children

BACKGROUND

Immunotherapy has been widely used in the treatment of allergic diseases. We evaluated the clinical efficacy of specific immunotherapy with extracts of Dermatophagoides pteronyssinus (Dp) and Dermatophagoides farinae (Df) in children with asthma.

METHODS

All 40 children had moderate-to-severe asthma and positive allergen tests for Dp and Df. All required daily medication. They were randomly assigned to two groups: Half of them received immunotherapy with subcutaneous injections of Dp and Df extracts, while the other half were not given immunotherapy. Participants were followed up for more than 6 months.

RESULTS

Children in both groups had apparent improvements in medication use and symptoms after 6 months. The mean medication scores declined from 3.6 +/- 1.14 to 1.7 +/- 0.66 in the immunotherapy group (p < 0.01) and from 3.35 +/- 0.87 to 2.4 +/- 1.09 in the control group (p < 0.01). There was a significant difference between the two groups (mean difference 0.95; p < 0.01). The symptom score improved in the immunotherapy group from 2.65 +/- 0.98 to 1.20 +/- 1.00 (p < 0.01) and in the control group from 2.55 +/- 0.99 to 1.40 +/- 0.88 (p < 0.01), with a significant difference between the two groups (mean difference 0.3; p < 0.01). The number of office visits in the immunotherapy group was greater than that of the controls, but the frequencies of emergency room visits and hospitalization decreased.

CONCLUSION

Our study showed that specific immunotherapy with Dp and Df was beneficial for asthmatic children.

Proteolytically inactive per a 10 allergen of Periplaneta americana modulates Th2 response and enhances IL-10 in mouse model

BACKGROUND

Purified allergens with reduced IgE reactivity are required to improve the safety and efficacy of allergen-specific immunotherapy (IT).

OBJECTIVE

The present study investigates the efficacy of purified cockroach allergen immunotherapy with proteolytically active and inactive Per a 10 in allergic mouse model.

METHODS

Balb/c mice were sensitized intraperitoneally with cockroach extract (CE) and purified allergen Per a 10 in separate groups. Mice were treated subcutaneously with phosphate-buffered saline (PBS), CE, active and inactive Per a 10 and challenged intranasally. Antigen specific IgE, IgG1 and IgG2a in serum and cytokines IL-4, IL-13, IFN-gamma, IL-10, TGF-beta in bronchoalveolar lavage (BAL) fluid and spleen culture supernatant (CS) were estimated by enzyme-linked immunosorbent assay. Lung histology was analyzed by hematoxylin and eosin staining.

RESULTS

IT with Per a 10 demonstrated significant reduction in IgE levels in serum, IL-4 levels in BAL fluid, CS, and eosinophilic infiltration in lungs than PBS-treated mice. This was associated with significantly increased IL-10 secretion in BAL fluid and CS. IT with Per a 10 effectively suppressed T-helper type 2 (Th2) response in mice sensitized with Per a 10 than CE group. Further, IT with inactive Per a 10 showed maximum reduction in systemic and airway inflammation and induced maximum IL-10 release in BAL fluid and CS than other antigens.

CONCLUSIONS

IT with Per a 10 effectively suppressed Th2 response and lung inflammation in Per a 10- or CE-sensitized mice. The beneficial effects of IT with inactive Per a 10 are more pronounced than active Per a 10.

A review of allergen-specific immunotherapy in human and veterinary medicine

This article reviews allergen-specific immunotherapy in human and veterinary medicine. Current hypotheses of possible mechanisms of actions are outlined. Indications, success rates, adverse effects and factors influencing outcome of therapy are discussed in humans, dogs, cats and horses.

Multiallergen immunotherapy for allergic rhinitis and asthma

The English and non-English language literature on allergen immunotherapy was reviewed for studies simultaneously using 2 or more distinct allergen extracts in either subcutaneous or sublingual immunotherapy. Thirteen studies were identified, 11 using subcutaneous injections, 1 using sublingual administration, and 1 using both. In studies with adequate information, administration of 2 extracts by means of either subcutaneous immunotherapy or sublingual immunotherapy was effective. In studies using multiple allergens, 3 studies showed clear efficacy, whereas in the other 2 studies, lack of efficacy might have been due to inadequate doses of extract or omission of clinically relevant allergens in the treatment regimen. It is concluded that simultaneous administration of more than 1 allergen extract is clinically effective. However, more studies are needed, particularly with more than 2 allergen extracts and with sublingual administration.

The response of bovine beta-lactoglobulin-specific T-cell clones to single amino acid substitution of T-cell core epitope

Cow's milk is one of the most common food allergens in the first year of life, with approximately 2.5% of infants experiencing an allergic reaction to it. Beta-lactoglobulin (BLG) is one of the major allergens in cow's milk. Previously, we reported that four of six T-cell clones (TCC) which were established from cow's milk allergy patients recognized BLGp97-117 as the core sequence and also recognized BLG in association with the human leucocyte antigen (HLA)-DRB1*0405 allele. Using two of these four TCCs, we evaluated the T-cell response to BLG peptides with single amino acid substitution or deletion and identified BLGp102-112 as the minimum essential region in BLGp97-117. In the alanine-scan assay, the proliferative responses of TCCs to pE108A disappeared, and the proliferative responses of TCCs to pC106A decreased. In the analog peptide proliferation assay, pY102S had retained some T-cell response to the two TCCs. Collecting these results, we propose a motif for the interaction between the HLA-DRB1*0405 allele and antigen peptide, and suggest that BLGp105-108 are important residues to retain the TCR/BLG-peptide/HLA complex. pY102A and pY102S are partial agonists for the T-cell receptor. These peptides might be considered as candidate peptides for the modification of the T-cell response to BLG in cow's milk allergy.

Anti-IgE antibodies for the treatment of IgE-mediated allergic diseases

The pharmacological purposes of the anti-IgE therapy are to neutralize IgE and to inhibit its production to attenuate type I hypersensitivity reactions. The therapy is based on humanized IgG1 antibodies that bind to free IgE and to membrane-bound IgE on B cells, but not to IgE bound by the high-affinity IgE.Fc receptors on basophils and mast cells or by the low-affinity IgE.Fc receptors on B cells. After nearly 20 years since inception, therapeutic anti-IgE antibodies (anti-IgE) have been studied in about 30 Phase II and III clinical trials in many allergy indications, and a lead antibody, omalizumab, has been approved for treating patients (12 years and older) with moderate-to-severe allergic asthma. Anti-IgE has confirmed the roles of IgE in the pathogenesis of asthma and helped define the concept "allergic asthma" in clinical practice. It has been shown to be safe and efficacious in treating pediatric allergic asthma and treating allergic rhinitis and is being investigated for treating peanut allergy, atopic dermatitis, latex allergy, and others. It has potential for use to combine with specific and rush immunotherapy for increased safety and efficacy. Anti-IgE thus appears to provide a prophylactic and therapeutic option for moderate to severe cases of many allergic diseases and conditions in which IgE plays a significant role. This chapter reviews the evolution of the anti-IgE concept and the clinical studies of anti-IgE on various disease indications, and presents a comprehensive analysis on the multiple intricate immunoregulatory pharmacological effects of anti-IgE. Finally, it reviews other approaches that target IgE or IgE-expressing B cells.

Lymphocyte Responses to Chymotrypsin- or Trypsin V-Digested beta-Lactoglobulin in Patients with Cow's Milk Allergy

Chymotrypsin- or trypsin V- (a mixture of trypsin and chymotrypsin) digested β-lactoglobulin (BLG) peptides were prepared and were confirmed to have much less immunoglobulin (lg)G and lgE reactivity compared with intact BLG by IgG inhibition enzymelinked immunosorbent assay and IgE dot blotting. The lymphocyte responses to intact BLG and these peptides were examined using peripheral blood mononuclear cells (PBMCs) from 10 patients with cow's milk allergy. The PBMCs from most patients had lower lymphocyte responses to chymotrypsin- and trypsin V-digested BLG peptides than those to intact BLG. However, PBMCs from one and two patients retained significant proliferative responses to both peptides and to only the former peptide, respectively. Interferon-c production stimulated by chymotrypsin-digested peptides was still detectable in all five patients tested. Chymotrypsindigested BLG reduced lgE reactivity but still induced some lymphocyte responses.

Intradermal immunization with ovalbumin-loaded poly-?-caprolactone microparticles conferred protection in ovalbumin-sensitized allergic mice

BACKGROUND

Although immunotherapy has been reported as the only treatment able to revert the T-helper type 2 (Th2) response, its administration has some disadvantages such as the requirement of multiple doses, possible side-effects provoked by conventional adjuvants and the risk of suffering an anaphylactic shock. For these reasons, drug-delivery systems appear to be a promising strategy due to its ability to (i) transport the allergens, (ii) protect them from degradation, (iii) decrease the number of administrations and (iv) act as immuno-adjuvants.

OBJECTIVE

The aim of this work was to evaluate the properties of poly-epsilon-caprolactone (PCL) microparticles as adjuvants in immunotherapy using ovalbumin (OVA) as an allergen model. For this purpose, the protection capacity of these microparticles (OVA PCL) against OVA allergy was studied in a murine model.

METHODS

The humoral and cellular-induced immune response generated by OVA encapsulated into PCL microparticles was studied by immunizing BALB/c mice intradermically. Also, OVA-sensitized mice were treated with OVA PCL and OVA adsorbed to aluminium hydroxide (OVA-Alum). Fifteen days after therapy, animals were challenged with OVA and different signs of anaphylactic shock were evaluated.

RESULTS

One single shot by an intradermal route with OVA PCL resulted in a Th2-type immune response. In OVA-sensitized mice, treatment with OVA PCL elicited high OVA-specific IgG but low levels of IgE. Furthermore, OVA PCL mice group displayed lower levels of serum histamine and higher survival rate in comparison with the positive control group.

CONCLUSION

The anaphylactic shock suffered by OVA PCL-treated mice was weaker than the one induced in the OVA-Alum group. Hence, the intradermal immunization with OVA PCL microparticles induced hyposensitization in OVA-allergic mice.

Allergen injection immunotherapy for seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis is the most common of the allergic diseases. Despite improved understanding of the pathophysiology of allergic rhinitis and advances in its pharmacological treatment, its prevalence has increased worldwide. For patients whose symptoms remain uncontrolled despite medical treatment, allergen injection immunotherapy is advised. An allergen-based treatment may reduce symptoms, the need for medication and modify the natural course of this disease.

OBJECTIVES

To evaluate the efficacy and safety of subcutaneous specific allergen immunotherapy, compared with placebo, for reducing symptoms and medication requirements in seasonal allergic rhinitis patients.

SEARCH STRATEGY

We searched the Cochrane Ear, Nose and Throat Disorders Group Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, Issue 1 2006), MEDLINE (1950 to 2006), EMBASE (1974 to 2006), Pre-MEDLINE, KOREAMED, INDMED, LILACS, PAKMEDINET, Scisearch, mRCT and the National Research Register. The date of the last search was February 2006.

SELECTION CRITERIA

All studies identified by the searches were assessed to identify randomised controlled trials involving participants with symptoms of seasonal allergic rhinitis and proven allergen sensitivity, treated with subcutaneous allergen specific immunotherapy or corresponding placebo.

DATA COLLECTION AND ANALYSIS

Two independent authors identified all studies reporting double-blind, placebo controlled randomised trials of specific immunotherapy in patients with seasonal allergic rhinitis due to tree, grass or weed pollens. Two authors independently performed quality assessment of studies. Data from identified studies were abstracted onto a standard extraction sheet and subsequently entered into RevMan 4.2.8. Analysis was performed using the Standardised Mean Difference (SMD) method and a random-effects model; P values < 0.05 were considered statistically significant. The primary outcome measures were symptom scores, medication use, quality of life and adverse events.

MAIN RESULTS

We retrieved 1111 publications of which 51 satisfied our inclusion criteria. In total there were 2871 participants (1645 active, 1226 placebo), each receiving on average 18 injections. Duration of immunotherapy varied from three days to three years. Symptom score data from 15 trials were suitable for meta-analysis and showed an overall reduction in the immunotherapy group (SMD -0.73 (95% CI -0.97 to -0.50, P < 0.00001)). Medication score data from 13 trials showed an overall reduction in the immunotherapy group (SMD of -0.57 (95% CI -0.82 to -0.33, p<0.00001)). Clinical interpretation of the effect size is difficult. Adrenaline was given in 0.13% (19 of 14085 injections) of those on active treatment and in 0.01% (1 of 8278 injections) of the placebo group for treatment of adverse events. There were no fatalities.

AUTHORS' CONCLUSIONS

This review has shown that specific allergen injection immunotherapy in suitably selected patients with seasonal allergic rhinitis results in a significant reduction in symptom scores and medication use. Injection immunotherapy has a known and relatively low risk of severe adverse events. We found no long-term consequences from adverse events.

In vivo and in vitro allergy diagnostics: it's time to reappraise the costs

BACKGROUND

The in vivo skin prick test (SPT) is widely considered less expensive than in vitro gamma-immunoglobulin E (IgE) determination in the diagnosis of allergy. The aim of the present paper is to evaluate the relevance of component-resolved in vitro diagnosis in comparison to extract-based diagnosis and the relative global costs in relation to clinical outcomes.

METHODS

For 50 individuals with suspected seasonal allergic rhinitis, we compared the costs of skin testing with those of specific IgE antibody measurement.

RESULTS

The costs were higher for in vitro than in vivo testing. However, the clinical information obtained using recombinant reagents allowed correct identification of the sensitizing molecule.

CONCLUSIONS

Recombinant allergens for specific IgE in vitro measurement provide more reliable information for immunotherapy prescription. This should be translated into a significant reduction in the overall costs sustained by the healthcare system.

Comparison of allergic indices in monosensitized and polysensitized patients with childhood asthma

Monosensitization differs both immunologically and clinically from polysensitization, and specific immunotherapy is more effective in patients sensitized only to a single pollen than in multiple-pollen sensitized patients. To further examine the differences between monosensitized and polysensitized allergies, allergic indices were examined in 68 monosensitized and 62 polysensitized patients with childhood asthma. Measurements included symptom scores, eosinophil counts, skin prick tests, serum total and specific IgE levels, and IL-10 levels, and were used to compare allergic indices between the two groups. Patients were followed for 18 months following immunotherapy to examine the effectiveness of the treatment. Symptom scores and total IgE levels were significantly higher in the polysensitized group than those in the monosensitized group (p<0.05). The levels of skin test response decreased significantly in both groups following immunotherapy. In the monosensitized group, symptom scores and specific IgE levels were significantly reduced after immunotherapy (p<0.05). In the polysensitized group, symptom scores were reduced after immunotherapy (p<0.05), but the degree of reduction was less than that of the monosensitized group (p<0.05). Moreover, in the polysensitized group, specific IgE levels after immunotherapy did not differ from that before immunotherapy. Serum IL-10 levels were not significantly increased after immunotherapy in either group. In conclusion, polysensitized patients tend to show higher allergic indices and immunotherapy might be less effective for these patients.

Accelerated immunotherapy schedules: review of efficacy and safety

OBJECTIVE

To provide a comprehensive evaluation of accelerated immunotherapy build-up schedules in terms of adverse reactions and clinical efficacy.

DATA SOURCES

Peer-reviewed studies and review articles were selected from the PubMed database for articles published in the years 1976 to 2006 using the following keywords: rush, cluster immunotherapy in combination with allergic rhinitis, asthma, Hymenoptera, and imported fire ant.

STUDY SELECTION

Studies were selected if they provided safety and efficacy information on accelerated allergen immunotherapy schedules. Most of the studies reviewed were double-blind, placebo controlled, but some open-observational studies were included if they provided immunotherapy safety or other information the author thought was relevant.

RESULTS

A wide range of systemic reactions were reported in the literature with inhalant allergens: ranging from 27% to 100% of the patients in rush immunotherapy studies and 0% to 79% of patients in the cluster studies. Predictors of systemic reactions with rush immunotherapy were forced expiratory volume in 1 second less than 80% of predicted and a high degree of skin test reactivity. Premedication clearly reduces the risk of systemic reactions with rush immunotherapy, but the effect on cluster schedules was not as clear.

CONCLUSION

Accelerated immunotherapy build-up schedules in selected patients may provide a rapid alternative to conventional build-up schedules without a significant increase in risk.

Component-resolved in vitro diagnosis in carrot allergy: Does the use of recombinant carrot allergens improve the reliability of the diagnostic procedure?

BACKGROUND

In Europe, pollen-related food allergy is the most frequent form of food allergy in adults. Reliability of current diagnostic procedures, however, is poor and therapeutic options are not available.

OBJECTIVES

In the present study, we created a panel of recombinant allergens from carrot and evaluated its potential in component-resolved in vitro diagnosis of carrot allergy.

METHODS

Recombinant (r) Dau c 1.0104, Dau c 1.0201 and Dau c 4 were cloned by a polymerase chain reaction strategy, expressed in Escherichia coli and purified. Carrot lipid transfer protein (LTP) was expressed in the yeast Pichia pastoris. Sera from 40 carrot-allergic patients were investigated. Twenty-one birch pollen-allergic subjects with negative open provocation to carrot and 20 non-allergic subjects were included as controls. IgE binding to recombinant allergens as well as to cross-reactive carbohydrate determinants (CCD) was measured by ELISA. Cross-reactivity between Dau c 1 isoforms and Bet v 1 was assayed by ELISA inhibition. Biological activity of the recombinant carrot allergens was assessed by histamine release assay and peripheral blood mononuclear cells stimulation.

RESULTS

Ninety-eight percent of the carrot-allergic patients were positive to at least one recombinant allergen; 98% reacted to rDau c 1.0104, 65% to rDau c 1.0201, 38% to rDau c 4 and 20% had IgE against CCD. Specificity using the recombinant allergens was high when compared with non-allergic controls, but low compared with birch-sensitized subjects without carrot allergy. Sensitization to Dau c 1.0201, however, proved to be highly specific for clinically relevant sensitization. Inhibition assays indicated the absence of LTP in carrot root extract, and epitope diversity between Dau c 1.0104, Dau c 1.0201 and Bet v 1.

CONCLUSIONS

Our panel of recombinant allergens from carrot can provide a standardized tool for in vitro diagnosis of carrot allergy, and for epitope studies.

Genetically modified allergens

For more than 90 years, allergen-specific immunotherapy, the only causative allergy treatment, has remained basically unchanged. The development of molecular biology techniques has led to the preparation of individual recombinant allergens from the most important allergen sources. Recombinant allergens can be used to determine the individual sensitization profile of allergic patients and have allowed the development of novel therapeutic tools. This article summarizes data on genetically modified recombinant allergen derivatives with reduced allergenic activity, which may be used to improve the safety and efficacy of specific immunotherapy.

Allergen rush immunotherapy increases interleukin (IL)-12 production and IL-12 receptor beta2 chain expression in patients with allergic asthma

Interleukin (IL)-12 production and IL-12 receptor (IL-12R) beta2 chain expression were investigated in patients with allergic asthma successfully treated with rush immunotherapy (RIT) and control patients with mild allergic asthma. Peripheral blood mononuclear cells (PBMCs) were stimulated with Dermatophagoides farinae (Der f), and production of cytokines was measured. Furthermore, the effects of cytokines on IL-12R beta2 chain expression on CD4(+) T cells were investigated. Production by PBMCs of IL-12 and IFN-gamma was significantly higher and production of IL-4 was significantly lower after stimulation with Der f allergen in RIT-treated patients than in control patients. Significant increases in the expression of IL-12R beta2 chain before and after stimulation of CD4(+) T cells with IL-12 or IFN-gamma were observed in RIT-treated patients compared with that in control patients. Allergen RIT increases IL-12 production and IL-12R beta2 chain expression and thus may convert cytokine production from Th2 to Th1 or Th0 type in allergic asthma.

[Efficacy of immunotherapy in the treatment of asthma]

Specific immunotherapy consists of the administration of allergen extracts to patients with allergic disease to achieve clinical tolerance to the causative allergens. Currently, it is the only etiologic treatment for respiratory allergy. A World Health Organization opinion paper published in 1997 defines immunotherapy as "the only form of treatment able to modify the natural course of allergic diseases". In patients with allergic rhinitis, several studies suggest that immunotherapy can modify the natural history of respiratory allergy by preventing the development of asthma in children with this disease. Numerous studies demonstrate its efficacy in IgE-mediated asthma and particularly in mild-to-moderate asthma. When complete avoidance of the allergen cannot be achieved with measures that allow the patient to lead a normal life, pharmacological treatment can help to control symptoms, but symptoms immediately return when treatment is interrupted. However, asthma care can be improved by allergen-specific treatment; immunotherapy may shift the immune response from an allergic pattern toward a more protective response, producing persistent improvement with reduction of symptoms and the need for pharmacological treatment. Numerous comparative studies with specific immunotherapy vs. placebo or pharmacological treatment have demonstrated the efficacy of this treatment and its advantages in control of the disease. Specific immunotherapy induces favorable clinical, biological and functional modifications in the course of allergic asthma. Significant improvement in clinical manifestations has been demonstrated, even with levels of allergen exposure higher than those at the beginning of treatment. This improvement is associated with a reduced need for antiinflammatory and bronchodilator treatment. Moreover, specific bronchial reactivity shows a clear improvement with disappearance of delayed response and a clear increase in the threshold for immediate response to the allergen. Reduction in nonspecific bronchial hyperreactivity and improvement in exercise-induced asthma are also observed. Several studies recommend an optimal duration of specific immunotherapy for allergic asthma of between 3 and 5 years to achieve maximal therapeutic efficacy. A direct relationship between treatment duration and the persistence of its effects has been observed. Moreover, the treatment is more effective when started early. The possible adverse effects related to systemic reactions should be borne in mind. Although these effects are infrequent, maximal precautions should be taken when administering this treatment. Immunotherapy is contraindicated in cases of severe asthma, heart disease, autoimmune disease and associated severe neoplastic processes. However, all the beneficial effects of immunotherapy are conditioned by an accurate and early etiological diagnosis confirming the causative allergen. The availability of high-quality allergen extracts is essential to obtain the desired effect. Inappropriate patient selection for this treatment is the main cause of its failure. The integral treatment of allergic asthma includes environmental measures, patient education, pharmacological treatment and, whenever possible, immunotherapy.

Component-resolved diagnosis of house-dust mite allergy with purified natural and recombinant mite allergens

BACKGROUND

Mites belong to the most frequent and potent allergen sources. Immunotherapy with mite allergen extracts is frequently performed if allergen avoidance is not possible or successful. However, highly controversial results have been reported for mite-specific immunotherapy.

OBJECTIVE

The aim of this study was to develop diagnostic concepts that may contribute to an improved selection of patients for immunotherapy with Der p allergen extracts and that may be used for immunological monitoring of patients undergoing this treatment.

METHODS

The IgE reactivity profiles to Der p extract were determined in a Middle European mite-allergic population by IgE immunoblotting and by using a panel of seven purified natural or recombinant Der p allergens (nDer p 1, nDer p 4, rDer p 2, rDer p 5, rDer p 7, rDer p 8, rDer p 10). Furthermore, we investigated the sensitization and cross-reactivity to house-dust- and storage-mite allergen extracts by CAP FEIA measurements and by IgE competition studies.

RESULTS

More than 95% of the patients could be diagnosed with a combination of nDer p 1 and rDer p 2. With the methods used, we could discriminate mite-allergic patients who were mainly sensitized to the major Der p allergens (Der p 1, Der p 2) from patients with a broad sensitization profile, including highly cross-reactive allergens (e.g. Der p 10: tropomyosin) as well as reactivity to storage mites.

CONCLUSIONS

Diagnostic tests containing the major mite allergens (i.e. Der p 1, Der p 2) and highly cross-reactive mite allergens (e.g. Der p 10) may improve the diagnostic selection of patients for immunotherapy with Der p extracts. These tests may also be used for the immunological monitoring of patients undergoing immunotherapy.