Certainties and doubts about sublingual and oral immunotherapy in children

A network-based approach for identifying suitable biomarkers for oral immunotherapy of food allergy

BACKGROUND

Oral immunotherapy (OIT) is a promising therapeutic approach to treat food allergic patients. However, concerns with regards to safety and long-term efficacy of OIT remain. There is a need to identify biomarkers that predict, monitor and/or evaluate the effects of OIT. Here we present a method to select candidate biomarkers for efficacy and safety assessment of OIT using the computational approaches Bayesian networks (BN) and Topological Data Analysis (TDA).

RESULTS

Data were used from fructo-oligosaccharide diet-supported OIT experiments performed in 3 independent cow's milk allergy (CMA) and 2 independent peanut allergy (PNA) experiments in mice. Bioinformatical approaches were used to understand the data structure. The BN predicted the efficacy of OIT in the CMA with 86% and indicated a clear effect of scFOS/lcFOS on allergy parameters. For the PNA model, this BN (trained on CMA data) predicted an efficacy of OIT with 76% accuracy and shows similar effects of the allergen, treatment and diet as compared to the CMA model. The TDA identified clusters of biomarkers closely linked to biologically relevant clinical symptoms and also unrelated and redundant parameters within the network.

CONCLUSIONS

Here we provide a promising application of computational approaches to a) compare mechanistic features of two different food allergies during OIT b) determine the biological relevance of candidate biomarkers c) generate new hypotheses to explain why CMA has a different disease pattern than PNA and d) select relevant biomarkers for future studies.

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.

Specific allergen immunotherapy for the treatment of atopic eczema

BACKGROUND

Specific allergen immunotherapy (SIT) is a treatment that may improve disease severity in people with atopic eczema (AE) by inducing immune tolerance to the relevant allergen. A high quality systematic review has not previously assessed the efficacy and safety of this treatment.

OBJECTIVES

To assess the effects of specific allergen immunotherapy (SIT), including subcutaneous, sublingual, intradermal, and oral routes, compared with placebo or a standard treatment in people with atopic eczema.

SEARCH METHODS

We searched the following databases up to July 2015: the Cochrane Skin Group Specialised Register, CENTRAL in the Cochrane Library (Issue 7, 2015), MEDLINE (from 1946), EMBASE (from 1974), LILACS (from 1982), Web of Science™ (from 2005), the Global Resource of EczemA Trials (GREAT database), and five trials databases. We searched abstracts from recent European and North American allergy meetings and checked the references of included studies and review articles for further references to relevant trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of specific allergen immunotherapy that used standardised allergen extracts in people with AE.

DATA COLLECTION AND ANALYSIS

Two authors independently undertook study selection, data extraction (including adverse effects), assessment of risk of bias, and analyses. We used standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified 12 RCTs for inclusion in this review; the total number of participants was 733. The interventions included SIT in children and adults allergic to either house dust mite (10 trials), grass pollen, or other inhalant allergens (two trials). They were administered subcutaneously (six trials), sublingually (four trials), orally, or intradermally (two trials). Overall, the risk of bias was moderate, with high loss to follow up and lack of blinding as the main methodological concern.Our primary outcomes were 'Participant- or parent-reported global assessment of disease severity at the end of treatment'; 'Participant- or parent-reported specific symptoms of eczema, by subjective measures'; and 'Adverse events, such as acute episodes of asthma or anaphylaxis'. SCORing Atopic Dermatitis (SCORAD) is a means of measuring the effect of atopic dermatitis by area (A); intensity (B); and subjective measures (C), such as itch and sleeplessness, which we used.For 'Participant- or parent-reported global assessment of disease severity at the end of treatment', one trial (20 participants) found improvement in 7/9 participants (78%) treated with the SIT compared with 3/11 (27%) treated with the placebo (risk ratio (RR) 2.85, 95% confidence interval (CI) 1.02 to 7.96; P = 0.04). Another study (24 participants) found no difference: global disease severity improved in 8/13 participants (62%) treated with the SIT compared with 9/11 (81%) treated with the placebo (RR 0.75, 95% CI 0.45 to 1.26; P = 0.38). We did not perform meta-analysis because of high heterogeneity between these two studies. The quality of the evidence was low.For 'Participant- or parent-reported specific symptoms of eczema, by subjective measures', two trials (184 participants) did not find that the SIT improved SCORAD part C (mean difference (MD) -0.74, 95% CI -1.98 to 0.50) or sleep disturbance (MD -0.49, 95% CI -1.03 to 0.06) more than placebo. For SCORAD part C itch severity, these two trials (184 participants) did not find that the SIT improved itch (MD -0.24, 95% CI -1.00 to 0.52). One other non-blinded study (60 participants) found that the SIT reduced itch compared with no treatment (MD -4.20, 95% CI -3.69 to -4.71) and reduced the participants' overall symptoms (P < 0.01), but we could not pool these three studies due to high heterogeneity. The quality of the evidence was very low.Seven trials reported systemic adverse reactions: 18/282 participants (6.4%) treated with the SIT had a systemic reaction compared with 15/210 (7.1%) with no treatment (RR 0.78, 95% CI 0.41 to 1.49; the quality of the evidence was moderate). The same seven trials reported local adverse reactions: 90/280 participants (32.1%) treated with the SIT had a local reaction compared with 44/204 (21.6%) in the no treatment group (RR 1.27, 95% CI 0.89 to 1.81). As these had the same study limitations, we deemed the quality of the evidence to also be moderate.Of our secondary outcomes, there was a significant improvement in 'Investigator- or physician-rated global assessment of disease severity at the end of treatment' (six trials, 262 participants; RR 1.48, 95% CI 1.16 to 1.88). None of the studies reported our secondary outcome 'Parent- or participant-rated eczema severity assessed using a published scale', but two studies (n = 184), which have been mentioned above, used SCORAD part C, which we included as our primary outcome 'Participant- or parent-reported specific symptoms of eczema, by subjective measures'.Our findings were generally inconclusive because of the small number of studies. We were unable to determine by subgroup analyses a particular type of allergen or a particular age or level of disease severity where allergen immunotherapy was more successful. We were also unable to determine whether sublingual immunotherapy was associated with more local adverse reactions compared with subcutaneous immunotherapy.

AUTHORS' CONCLUSIONS

Overall, the quality of the evidence was low. The low quality was mainly due to the differing results between studies, lack of blinding in some studies, and relatively few studies reporting participant-centred outcome measures. We found limited evidence that SIT may be an effective treatment for people with AE. The treatments used in these trials were not associated with an increased risk of local or systemic reactions. Future studies should use high quality allergen formulations with a proven track record in other allergic conditions and should include participant-reported outcome measures.

Selection of patients for sublingual versus subcutaneous immunotherapy

Allergen immunotherapy is the sole treatment for IgE-mediated allergic diseases directed at the underlying mechanism. The two widely accepted administration routes are sublingual (SLIT) and subcutaneous (SCIT). We reviewed how patients should best be selected for immunotherapy and how the optimal administration route can be defined. Before deciding SCIT or SLIT, appropriate selection of patients for allergen immunotherapy (AIT) is mandatory. To be eligible for AIT, subjects must have a clear medical history of allergic disease, with exacerbation of symptoms on exposure to one or more allergens and a corresponding positive skin or in vitro test. Then the route of administration should be based on: published evidence of clinical and immunologic efficacy (which varies per allergic disease and per allergen); mono- or multi-allergen immunotherapy, for SLIT multi-allergen immunotherapy was not effective; safety: adverse events with SLIT are more frequent, but less severe; and, costs and patient preferences, closely related to adherence issues. All these are discussed in the article.

Immunotherapy - risk/benefit in food allergy

Food allergy is a growing health concern in the westernized world with approx. 6% of children suffering from it. A lack of approved treatment has led to strict avoidance of the culprit food proteins being the only standard of care. Nowadays in-depth research is conducted to evaluate the possible use of allergen-specific immunotherapy (SIT) as an active therapeutic option for food allergy. Various routes of administration for the immunotherapy are investigated, including subcutaneous, oral, sublingual, and epicutaneous, and some appear to be successful in inducing a temporary tolerant state. Most research has been conducted with oral immunotherapy due to its efficacious and relatively safe profile. Increasing interest is dedicated to safer and more convenient approaches, such as sublingual and epicutaneous SIT; however, doubts exist about their possible capacity to induce temporary tolerant state and permanent oral tolerance. The high frequency of allergic adverse reactions of the various approaches and the inability to achieve permanent oral tolerance have highlighted the need of refinements in the strategies. A promising strategy for preventing IgE cross-linking and thus enhancing safety of SIT, while still activating T cells, is the use of tolerogenic peptides. The implementation of such an immunotherapy approach has the potential of not only increasing the chance of achieving a permanent state of tolerance, but also improving the safety and tolerability of the therapy. Immunotherapy for food allergy is still not ready for the clinic, but current and upcoming studies are dedicated to collect enough evidence for the possible implementation of allergen-SIT as a standard treatment for food allergy.

Efficacy and safety of a once-daily sublingual immunotherapy without escalation regimen in house dust mite-induced allergic rhinitis

BACKGROUND

The conventional escalation regimen for sublingual immunotherapy (SLIT) in patients with allergic rhinitis has been proven to be safe and successful in reducing allergic symptoms. However, few studies compared the efficacy and safety between a conventional escalation regimen for SLIT and once-daily SLIT. The aim of the present study was to compare the efficacy and safety of once-daily SLIT without escalation (SLITsE) to conventional escalation therapy (SLITwE).

METHODS

This study was a nonrandomized open label observational study. In total, 153 patients suffering from allergic rhinitis symptoms and sensitized to the perennial house dust mite allergens Dermatophagoides pteronyssinus and Dermatophagoides farinae, were enrolled in this study from July 2008 to December 2009. The patients were divided into 2 groups, SLITwE and SLITsE. Each patient was followed with a diary card on which a symptom score, a rescue medication score, and adverse events were recorded.

RESULTS

All of the nasal symptoms, including rhinorrhea, sneezing, nasal obstruction, itching, and olfactory symptoms, defined as a total nasal symptom score, were reduced after 6 months in both groups (p < 0.05). The rescue medication score, defined as the sum of all of the allergy medications used, also decreased in both groups. Adverse events were similar in both groups, and no major adverse events, such as anaphylaxis, were reported.

CONCLUSION

Once-daily SLITsE was well tolerated and showed safe and comparable efficacy compared with a conventional SLITwE regimen.

Immunotherapy in asthma

Asthma is a chronic inflammatory disorder of the airways in which many cells and cellular elements play a role. Chronic inflammation is associated with airway hyper-responsiveness that leads to recurrent episodes of wheezing, breathlessness, chest tightness and coughing, as well as variable airflow obstruction within the lung. With time, such airflow obstruction may become permanent due to remodeling. It has been treated for more than 100 years by subcutaneous immunotherapy with allergen extracts but in recent years, other forms and types of immunotherapy have been introduced. Perhaps the most successful of these to date, is sublingual immunotherapy, which has attained significant usage in European countries but has yet to make inroads into clinical practice in North America. Other mechanisms to modify the inflammatory responses of asthma have included immunotherapy with recombinant allergens, the use of allergen peptides targeting antigen-specific T cells and the administration of Toll-like receptor agonists coupled to allergen proteins. As the inflammatory responses in asthma frequently involve IgE, a modified monoclonal antibody to IgE and interfering with its binding to the IgE receptor have gained acceptance for treating severe allergic asthma. Other monoclonal antibodies or recombinant receptor antagonists are being assessed for their ability to block other contributors to the inflammatory response. Finally, attempts have been made to generate autoantibody responses to cytokines implicated in asthma. Most of these therapies aim to modify or inhibit the so-called Th 2 immune response, which is implicated in many forms of asthma, or to inhibit cytokines involved in these responses. However, an added benefit of classical immunotherapy seems to be the ability to prevent the allergic progression to new sensitivities and new forms of allergic disease.

Efficacy of high-dose sublingual immunotherapy in children allergic to house dust mites in real-life clinical practice

BACKGROUND

The aim of the study was to evaluate the efficacy and safety of high-dose mite sublingual immunotherapy (SLIT) administered in children with allergic rhinitis in real-life clinical practice. Moreover, we analysed the clinical course of asthma severity.

METHODS

Retrospective, observational, monocentre study. Medical records of patients treated between 2001 and 2008 were reviewed. Patients received a standardised Dermatophagoides pteronyssinus+Dermatophagoides farinae extract (300 IR/ml) manufactured by Stallergenes (Staloral(®) 300). Patients were evaluated before SLIT initiation and at 6, 12, 24, 36 and 48 months. Global assessment of SLIT efficacy was measured using a visual analogue scale (VAS) and a rhinitis medication consumption score (RMCS). A global asthma score was used to estimate the clinical course of asthma severity.

RESULTS

We obtained data from 78 patients, 43.6% male. The mean (± SD) age was 11.0 ± 3.0 years. Most patients (69.2%) suffered from allergic rhinitis plus asthma. Patient evaluation of allergy severity (VAS) revealed a highly significant improvement between baseline and six months (p < 0.001, Wilcoxon test): 4.0 ± 1.7 cm vs. 7.3 ± 4.6 cm. This improvement was maintained throughout the four-year follow-up period. The use of medications (RMCS) was significantly reduced in the first six months (4.6 ± 2.5 points at baseline vs. 0.8 ± 1.6 points at six months visit, p < 0.001, Wilcoxon test) and remained very low until the end of follow-up. We did not find a temporal improvement in asthma severity.

CONCLUSIONS

This retrospective study indicates that high-dose SLIT in children with rhinitis caused by house dust mites is well-tolerated and could be an effective treatment.