Is there a role for anti-IgE in combination with specific allergen immunotherapy?

The use of biologics in children with allergic rhinitis and chronic rhinosinusitis: Current updates

The therapeutic goals of the treatment of allergic rhinitis (AR) and chronic rhinosinusitis (CRS) are symptom relief, avoiding complications, and improving quality of life. In the treatment of AR and CRS, several limitations of currently prescribed medicines have been identified. Antihistamine administration (both oral and topical) together with intranasal corticosteroids bring relief to the majority of patients, but their dependency on the medications and a necessity to maintain strict compliance with regular medication regimes pose a challenge. Immunotherapeutic agents are an option in some patients, but polysensitized patients, the risk of anaphylaxis, and the need for daily administration for years are limiting it from becoming the main therapy modality. Immunotherapy in any form requires commitment by the patient, which renders adherence and compliance issues particularly relevant. The procedure involved are generally time-consuming and entail an associated risk of severe adverse reactions. The use of biologics could overcome the limitations of other therapeutic modalities. They could be used as a monotherapy or combined with pre-existing medications. The benefits of targeted therapy include less adverse effects and optimal efficacy. The aim of the present review was to investigate the collective literature to date pertaining to the role of biologics in managing children with AR and CRS.

Allergen immunotherapy as add-on to biologic agents

PURPOSE OF REVIEW

In this review, we sought to outline many of the recent evidences about the available clinical trials in which biologic agents [i.e. omalizumab (OMA)] were associated as add-on to allergen-specific immunotherapy (AIT).

RECENT FINDINGS

The available literature shows that OMA may be a valuable option as add-on to AIT for respiratory allergy, or food desensitization, especially in the escalation or build-up phases, in which adverse events are more commonly expected. The encouraging data for hymenoptera venom allergy remain limited to case reports, and no structured clinical trial is available.

SUMMARY

Over the past decade, studies of OMA used with AIT have shown promising results. Today, big randomized, double-blind, placebo-controlled trials are needed to better select those patients who would benefit from the addition of OMA (or other biologic agents) to AIT, as well as optimal dosing schedules, optimal duration of treatments and, finally, adequate evaluation about pharmacoeconomic aspects.

International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis

BACKGROUND

Critical examination of the quality and validity of available allergic rhinitis (AR) literature is necessary to improve understanding and to appropriately translate this knowledge to clinical care of the AR patient. To evaluate the existing AR literature, international multidisciplinary experts with an interest in AR have produced the International Consensus statement on Allergy and Rhinology: Allergic Rhinitis (ICAR:AR).

METHODS

Using previously described methodology, specific topics were developed relating to AR. Each topic was assigned a literature review, evidence-based review (EBR), or evidence-based review with recommendations (EBRR) format as dictated by available evidence and purpose within the ICAR:AR document. Following iterative reviews of each topic, the ICAR:AR document was synthesized and reviewed by all authors for consensus.

RESULTS

The ICAR:AR document addresses over 100 individual topics related to AR, including diagnosis, pathophysiology, epidemiology, disease burden, risk factors for the development of AR, allergy testing modalities, treatment, and other conditions/comorbidities associated with AR.

CONCLUSION

This critical review of the AR literature has identified several strengths; providers can be confident that treatment decisions are supported by rigorous studies. However, there are also substantial gaps in the AR literature. These knowledge gaps should be viewed as opportunities for improvement, as often the things that we teach and the medicine that we practice are not based on the best quality evidence. This document aims to highlight the strengths and weaknesses of the AR literature to identify areas for future AR research and improved understanding.

In the strategies to prevent asthma exacerbations, allergic asthma needs specific treatment

No generally accepted definition of asthma exacerbation is thus far available, though in 2012 an expert committee endorsed by the National Institute of Health proposed such definition as "a worsening of asthma requiring the use of systemic corticosteroids to prevent a serious outcome". Graham and Eid reviewed the impact of asthma exacerbations, and noted that, analysing the outcomes with existing treatments, many patients with asthma remain symptomatic and experience exacerbations. This requires the introduction of new strategies to more effectively reduce the exacerbation risk, based on correct diagnosis, stopping smoking, correct inhaler technique, consistent adherence, weight management, and gaining control with the addition of medication". Indeed, as allergic asthma is the most common form, a specific approach by allergen immunotherapy should receive more attention. Actually, the efficacy of immunotherapy in allergic asthma, by the subcutaneous or the sublingual route, is supported by robust meta-analyses. The most important allergen source causing asthma is the house dust mite, but an increasing role for molds is apparent due to the ongoing climate change.

Combination treatment with omalizumab and rush immunotherapy for ragweed-induced allergic rhinitis: Inhibition of IgE-facilitated allergen binding

BACKGROUND

The combination of anti-IgE (omalizumab) therapy with ragweed injection immunotherapy for seasonal allergic rhinitis results in a significant reduction in systemic side effects and enhanced efficacy compared with immunotherapy alone. One proposed mechanism of immunotherapy is to induce regulatory antibodies that inhibit facilitated antigen presentation.

OBJECTIVES

We sought to determine whether the combination protocol has a cumulative effect on inhibition of facilitated antigen presentation both during and after discontinuation of treatment.

METHODS

Ragweed allergen immunotherapy with and without omalizumab therapy was tested in a 4-arm, double-blind, placebo-controlled study. Flow cytometry was used to detect serum inhibitory activity for IgE-facilitated CD23-dependent allergen binding to B cells as a surrogate marker for facilitated antigen presentation. Serum ragweed-specific IgG4 was measured by means of ELISA.

RESULTS

Immunotherapy alone resulted in partial inhibition of allergen-IgE binding after 5 to 19 weeks of treatment compared with baseline (P < .01). Complete inhibition of allergen-specific IgE binding was observed in both treatment groups receiving omalizumab (P < .001). Allergen-specific IgG4 levels were only increased after immunotherapy (P < .05), both in the presence and absence of anti-IgE treatment. Combined treatment resulted in the induction of long-lasting inhibitory antibody function for up to 42 weeks compared with either treatment alone.

CONCLUSION

Ragweed immunotherapy induced serum regulatory antibodies that partially blocked binding of allergen-IgE complexes to B cells. Additional treatment with anti-IgE, by directly blocking IgE binding to CD23, completely inhibited allergen-IgE binding.

CLINICAL IMPLICATIONS

The combination of ragweed immunotherapy and anti-IgE resulted in prolonged inhibition of allergen-IgE binding compared with either treatment alone, events that might contribute to enhanced efficacy.

Egg oral immunotherapy in nonanaphylactic children with egg allergy

BACKGROUND

There is no current active treatment for food allergy. Traditional injection immunotherapy has been proved unsafe, and thus there is a need for other forms of immunotherapy.

OBJECTIVE

The purpose was to study the safety and immunologic effects of egg oral immunotherapy (OIT). The short-term goal was to desensitize subjects to protect against accidental ingestion reactions. The eventual goal was to induce lasting clinical and immunologic tolerance.

METHODS

Subjects with a history of egg allergy but without a history of anaphylaxis to egg underwent a 24-month egg OIT protocol involving modified rush, build-up, and maintenance phases. Double-blind, placebo-controlled food challenges were performed at study conclusion. Egg-specific IgE and IgG concentrations were followed.

RESULTS

Seven subjects completed the protocol. Egg-specific IgG concentrations increased significantly, whereas egg-specific IgE concentrations did not significantly change. Three subjects tolerated known or possible accidental egg ingestions while receiving OIT. During double-blind, placebo-controlled food challenges at study conclusion, all tolerated significantly more egg protein than at study onset and than that found in the typical accidental exposure. Two subjects demonstrated oral tolerance.

CONCLUSION

This study provides proof of concept that OIT can be safely used for patients with egg allergy without a history of anaphylaxis to egg. Egg OIT does not heighten sensitivity to egg and might protect against reaction on accidental ingestion. Whether OIT will induce clinical oral tolerance cannot be concluded from this initial cohort.

CLINICAL IMPLICATIONS

Use of allergen-specific OIT to protect subjects with food allergy from reaction on accidental ingestion would represent a significant paradigm change in the treatment of food allergy.

Intramuscular immunization with DNA construct containing Der p 2 and signal peptide sequences primed strong IgE production

BACKGROUND

Previous studies demonstrated that allergen gene vaccination induced TH1-skewed responses and inhibited IgE production. This study evaluated and characterized the immune responses induced by three DNA constructs encoding different forms of Der p 2 for safe and efficacious vaccination against mite allergy.

METHODS

Mice were immunized intramuscularly with DNA constructs encoding a major mite allergen, Der p 2, without a signal peptide (p2), with a signal peptide (p52), and with a signal peptide plus lysosomal-targeting sequence (p52-LA), respectively, followed by TH2-skewed protein challenge. Antibody and T-cell cytokine responses were assessed by ELISA. Primed dendritic cells (DCs) were adoptively transferred to naïve mice and humoral responses were examined after protein challenge. The circulating Der p 2 protein was detected by sandwich ELISA.

RESULTS

Mice immunized with p52-LA showed strong and clear-cut TH1-type response, as evident by high IFN-gamma production and elevated levels of Der p 2-specific IgG2a production whereas construct p2 induced only moderate levels of TH1 response. In contrast, mice immunized with construct p52 showed a mixed TH1/TH2 phenotype and produced substantial circulating Der p 2 protein. Mice adoptively transferred with DCs primed by p52 construct, but not by the p2 or p52-LA constructs, were sensitized to produce high levels of Der p 2-specific IgE.

CONCLUSIONS

Immunization with DNA construct encoding a signal peptide could potentially prime TH2-skewed responses and IgE production. The additional inclusion of lysosomal-targeting sequences to such construct could improve the safety and efficacy of DNA vaccination against allergy.

Food allergy in children

Food allergy is being increasingly recognised with the highest prevalence being in preschool children. Pathogenesis varies so diagnosis rests on careful history and clinical examination, appropriate use of skin prick and serum-specific IgE testing, food challenge, and supervised elimination diets. A double blind placebo controlled food challenge is the gold standard diagnostic test. Avoidance of the allergenic food is the key towards successful management. IgE mediated food allergy may present as a potentially fatal anaphylactic reaction, and management consists of the appropriate use of adrenaline (epinephrine) and supportive measures. Sensitisation remains a key target for intervention. Disease modifying agents are currently under trial for managing difficult allergies. Management requires a multidisciplinary approach and follow up.

Inhibition of interleukin-4 production in activated T cells via the downregulation of AP-1/NF-AT activation by N-lauroyl-D-erythro-sphingosine and N-lauroyl-D-erythro-C20-sphingosine

Allergic diseases are hypersensitivity disorders that are associated with the generation of specific immunoglobulin E (IgE) in response to environmental allergens. Interleukin (IL)-4, which is primarily produced by the CD4(+) T cells, is an important stimulus for the switching of the antibody isotype to IgE in both mice and humans. In a previous study, we demonstrated that ceramide derivatives coupled with a lauroyl group exerted strong inhibitory effects on IL-4 production in T cells. In this study, we attempted to characterize the mechanisms underlying the inhibition of IL-4 production in T cells. Two ceramide derivatives, N-lauroyl-D-erythro-sphingosine and N-lauroyl-D-erythro-C(20)-sphingosine (hereafter abbreviated as LES and LECS, respectively), were shown to significantly inhibit the production of IL-4 in both primary CD4(+) T cells and EL4 T thymoma cells in a dose-dependent manner. LES and LECS also inhibited the activity of the IL-4 gene promoter in EL4 cells transiently transfected with IL-4 gene promoter constructs, but this effect was impaired in EL4 cells that had been transfected with an IL-4 promoter construct deleted of a P4 site harboring the AP-1 and NF-AT binding sites. Furthermore, LES and LECS inhibited the DNA binding activities of both AP-1 and NF-AT transcription factors. In addition, LES and LECS were demonstrated to suppress PMA-stimulated PKC activity, although they exerted no significant effects on the protein levels of the conventional PKCs. These results indicate that the ceramides, LES and LECS, may inhibit the production of IL-4 in the activated T cells, via the downregulation of AP-1/NF-AT activation and PKC activity.

Formononetin, a phyto-oestrogen, and its metabolites up-regulate interleukin-4 production in activated T cells via increased AP-1 DNA binding activity

Phyto-oestrogens are polyphenolic non-steroidal plant compounds with oestrogen-like biological activity. Phyto-oestrogens have many biological effects including oestrogen agonist/antagonist properties. However, the effect of phyto-oestrogens on allergic responses remains unclear. In this study we investigated whether formononetin, a phyto-oestrogen, and its metabolites, daidzein and equol, affect production of interleukin-4 (IL-4), a pro-inflammatory cytokine closely associated with allergic immune response, in primary CD4+ T cells and EL4 T lymphoma cells. Formononetin, daidzein and equol significantly enhanced IL-4 production from both CD4+ T cells and EL4 cells in a dose-dependent manner. Formononetin, daidzein and equol also enhanced IL-4 gene promoter activity in EL4 cells transiently transfected with IL-4 gene promoter constructs, but this effect was impaired in EL4 cells transfected with an IL-4 promoter construct deleted of P4 site carrying nuclear factor of activated T cells (NF-AT) and activator protein-1 (AP-1) binding sites. In addition, formononetin, daidzein and equol increased AP-1 DNA binding activities while did not affect NF-AT DNA binding activities. The enhancing effects on IL-4 production and AP-1 DNA binding activities were abrogated by specific inhibitors for phosphatidylinositol-3-kinase (PI3K), protein kinase C (PKC) and p38 mitogen-activated protein kinase (MAPK), indicating that formononetin, daidzein and equol might enhance IL-4 production by increased activation of AP-1 through the PI3-K/PKC/p38 MAPK signalling pathway. These results suggest that phyto-oestrogens and some of their metabolites may increase allergic responses via the enhancement of IL-4 production in T cells.

Inhibitory activity of a ceramide library on interleukin-4 production from activated T cells

Allergic diseases are hypersensitivity disorders associated with the production of specific immunoglobulin E (IgE) to environmental allergens. Interleukin (IL)-4, produced primarily by CD4(+) T cells, is an important stimulus for the switch of the antibody isotype to IgE in both mice and humans. In this study we investigated the inhibitory activity of IL-4 production in activated T cells by screening ceramide derivatives prepared by solid phase combinatorial chemistry. Many ceramide derivatives significantly inhibited IL-4 production in T cells. In particular, ceramide derivatives with a lauroyl group showed strong inhibitory activities on IL-4 production in both phorbol 12-myristate 13-acetate (PMA)-activated EL4 T cells and antigen-primed cells, suggesting that they can be used as compounds for the development of anti-allergic agents.

Anti-IgE therapy in allergic disease

PURPOSE OF REVIEW

Recombinant monoclonal humanized anti-IgE has put forward a fundamentally new concept for the control of allergic disorders. This review will present recent data from clinical studies with anti-IgE in asthma, allergic rhinitis, and food allergy and will examine the place of anti-IgE among current therapeutic options for the treatment of asthma.

RECENT FINDINGS

Therapy with anti-IgE depresses circulating free IgE to the limits of detection, inhibits early- and late-phase responses to allergens, suppresses inflammation and improves the control of allergic diseases. In moderate to severe asthma it results in fewer exacerbations and a lower requirement for both corticosteroids and beta-agonists. IgE appears to be an important regulator of high-affinity Fc receptors (FcepsilonRI) and, in the mouse, to enhance mast cell survival and activation. IgE receptors have been found on diverse inflammatory cells. Anti-IgE reduces the expression of FcepsilonRI on inflammatory cells. Current work has documented a marked decrease in tissue eosinophils, lymphocytes, and interleukin-4-positive cells by anti-IgE treatment and has provided insight into the mechanisms underlying improved control of asthma.

SUMMARY

Clinical studies with anti-IgE have promoted and will continue to advance the understanding of IgE-mediated disease mechanisms. They have documented its efficacy in the treatment of allergic diseases, but much remains to be learned about the most effective clinical strategies and the selection of patients for therapy.

Inhibition of allergen-specific IgE reactivity by a human Ig Fcgamma-Fcepsilon bifunctional fusion protein

BACKGROUND

Coaggregating FcepsilonRI with FcgammaRII receptors holds great potential for treatment of IgE-mediated disease by inhibiting FcepsilonRI signaling. We have previously shown that an Fcgamma-Fcepsilon fusion protein, human IgG-IgE Fc fusion protein (GE2), could inhibit FcepsilonRI-mediated mediator releases in vitro and in vivo.

OBJECTIVE

We sought to test whether GE2 was capable of blocking mediator release from FcepsilonRI cells sensitized with IgE in vivo or in vitro before exposure to GE2, a critical feature for GE2 to be clinically applicable.

METHODS

GE2 was tested for its ability to inhibit Fel d 1-induced mediator release from human blood basophils from subjects with cat allergy, human lung-derived mast cells, human FcepsilonRIalpha transgenic mice sensitized with human cat allergic serum, and rhesus monkeys naturally allergic to the dust mite Dermatophagoides farinae.

RESULTS

Basophils from subjects with cat allergy and lung mast cells degranulate when challenged with Fel d 1 and anti-IgE, respectively. GE2 itself did not induce mediator release but strongly blocked this Fel d 1- and anti-IgE-driven mediator release. GE2 was able to block Fel d 1-driven passive cutaneous anaphylaxis at skin sites sensitized with human serum from subjects with cat allergy in human FcepsilonRIalpha transgenic mice, but by itself, GE2 did not induce a passive cutaneous anaphylaxis reaction. Finally, GE2 markedly inhibited skin test reactivity to D farinae in monkeys naturally allergic to this allergen, with complete inhibition being observed at 125 ng.

CONCLUSION

GE2 is able to successfully compete for FcepsilonRs and FcgammaRs on cells presensitized in vitro and in vivo and lead to inhibition of IgE-mediated reactivity through coaggregation of FcepsilonRI with FcgammaRII.

The co-seasonal application of anti-IgE after preseasonal specific immunotherapy decreases ocular and nasal symptom scores and rescue medication use in grass pollen allergic children

BACKGROUND

Specific immunotherapy (SIT) and treatment with anti-immunoglobulin (Ig)E antibody are complementary approaches to treat allergic rhinoconjunctivitis, which may be used for single or combined treatment.

OBJECTIVE

A randomized, double-blind, placebo-controlled trial was conducted to compare the efficacy of single and combined treatment with SIT and anti-IgE (Omalizumab) in reducing symptom severity and rescue medication use.

METHODS

A total of 221 subjects with birch and grass pollen allergic rhinoconjunctivitis aged 6-17 years were analysed during the grass pollen season. Group A (SITbirch + placebo) served as a reference group obtaining no effective treatment for grass pollen allergy. Group B received anti-IgE monotherapy during grass pollen season, group C SIT grass pollen monotherapy, and group D the combined treatment of SIT and Omalizumab.

RESULTS

Preseasonal treatment with grass pollen SIT alone compared with SIT with the nonrelated allergen did not reduce symptoms or rescue medication use. Anti-IgE monotherapy significantly diminished rescue medication use and number of symptomatic days. The combined treatment with SIT and anti-IgE showed superior efficacy on symptom severity compared with anti-IgE alone.

CONCLUSIONS

Co-seasonal Omalizumab therapy showed considerable effects in children with seasonal allergic rhinitis. The combination of SIT plus Omalizumab was clinically superior to each treatment alone during the first year of observation.