The Complex Type 2 Endotype in Allergy and Asthma: From Laboratory to Bedside

International Consensus on Allergen Immunotherapy II: Mechanisms, standardization, and pharmacoeconomics

This article continues the comprehensive international consensus (ICON) statement on allergen immunotherapy (AIT). The initial article also recently appeared in the Journal. The conclusions below focus on key mechanisms of AIT-triggered tolerance, requirements in allergen standardization, AIT cost-effectiveness, and regulatory guidance. Potential barriers to and facilitators of the use of AIT are described in addition to future directions. International allergy specialists representing the European Academy of Allergy and Clinical Immunology; the American Academy of Allergy, Asthma & Immunology; the American College of Allergy, Asthma and Immunology; and the World Allergy Organization critically reviewed the existing literature and prepared this summary of recommendations for best AIT practice. The authors contributed equally and reached consensus on the statements presented herein.

NK cells contribute to persistent airway inflammation and AHR during the later stage of RSV infection in mice

RSV can lead to persistent airway inflammation and AHR and is intimately associated with childhood recurrent wheezing and asthma, but the underlying mechanisms remain unclear. There are high numbers of NK cells in the lung, which not only play important roles in the acute stage of RSV infection, but also are pivotal in regulating the pathogenesis of asthma. Therefore, in this study, we assumed that NK cells might contribute to persistent airway disease during the later stage of RSV infection. Mice were killed at serial time points after RSV infection to collect samples. Leukocytes in bronchoalveolar lavage fluid (BALF) were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. Cytokines were detected by ELISA, and NK cells were determined by flow cytometry. Rabbit anti-mouse asialo-GM-1 antibodies and resveratrol were used to deplete or suppress NK cells. Inflammatory cells in BALF, lung tissue damage and AHR were persistent for 60 days post-RSV infection. Type 2 cytokines and NK cells were significantly increased during the later stage of infection. When NK cells were decreased by the antibodies or resveratrol, type 2 cytokines, the persistent airway inflammation and AHR were all markedly reduced. NK cells can contribute to the RSV-associated persistent airway inflammation and AHR at least partially by promoting type 2 cytokines. Therefore, therapeutic targeting of NK cells may provide a novel approach to alleviating the recurrent wheezing subsequent to RSV infection.

European Symposium on Precision Medicine in Allergy and Airways Diseases: Report of the European Union Parliament Symposium (October 14, 2015)

The European Academy of Allergy and Clinical Immunology (EAACI), the European Rhinologic Society (ERS), and the European Medical Association (EMA) organized, on October 14, 2015, a symposium in the European Parliament in Brussels on Precision Medicine in Allergy and Airways Diseases, hosted by MEP David Borrelli, and with active participation of the EU Commissioner for Health and Food Safety Vytenis Andriukaitis, MEP Sirpa Pietikainen, Chair of the European Parliament Interest Group on Allergy and Asthma, the European Respiratory Society (ERS), the European Federations of Allergy and Airways Diseases Patients Associations (EFA), the Global Allergy and Asthma European Network (Ga2len), Allergic Rhinitis and Its Impact on Asthma (ARIA), and the Respiratory Effectiveness Group (REG). The socioeconomic impact of allergies and chronic airways diseases cannot be underestimated, as they represent the most frequently diagnosed chronic noncommunicable diseases in the EU; 30% of the total European population is suffering from allergies and asthma, and more than half are deprived from adequate diagnosis and treatment. Precision medicine represents a novel approach, embracing four key features: personalized care based on molecular, immunologic, and functional endotyping of the disease, with participation of the patient in the decision-making process of therapeutic actions, and considering predictive and preventive aspects of the treatment. Implementation of precision medicine into clinical practice may help to achieve the arrest of the epidemic of allergies and chronic airways diseases. Participants underscored the need for optimal patient care in Europe, supporting joint action plans for disease prevention, patient empowerment, and cost-effective treatment strategies.

A randomized trial of the efficacy and safety of quilizumab in adults with inadequately controlled allergic asthma

Background

Quilizumab, a humanized IgG1 monoclonal antibody, targets the M1-prime segment of membrane-expressed IgE, leading to depletion of IgE-switched and memory B cells. In patients with mild asthma, quilizumab reduced serum IgE and attenuated the early and late asthmatic reaction following whole lung allergen challenge. This study evaluated the efficacy and safety of quilizumab in adults with allergic asthma, inadequately controlled despite high-dose inhaled corticosteroids (ICS) and a second controller.

Methods

Five hundred seventy-eight patients were randomized to monthly or quarterly dosing regimens of subcutaneous quilizumab or placebo for 36 weeks, with a 48-week safety follow-up. Quilizumab was evaluated for effects on the rate of asthma exacerbations, lung function, patient symptoms, serum IgE, and pharmacokinetics. Exploratory analyses were conducted on biomarker subgroups (periostin, blood eosinophils, serum IgE, and exhaled nitric oxide).

Results

Quilizumab was well tolerated and reduced serum total and allergen-specific IgE by 30–40 %, but had no impact on asthma exacerbations, lung function, or patient-reported symptom measures. At Week 36, the 300 mg monthly quilizumab group showed a 19.6 % reduction (p = 0.38) in the asthma exacerbation rate relative to placebo, but this was neither statistically nor clinically significant. Biomarker subgroups did not reveal meaningful efficacy benefits following quilizumab treatment.

Conclusions

Quilizumab had an acceptable safety profile and reduced serum IgE. However, targeting the IgE pathway via depletion of IgE-switched and memory B cells was not sufficient for a clinically meaningful benefit for adults with allergic asthma uncontrolled by standard therapy.

Trial registration

ClinicalTrials.gov NCT01582503

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0347-2) contains supplementary material, which is available to authorized users.

Asthma phenotypes and endotypes: a personalized approach to treatment

PURPOSE OF REVIEW

Asthma is quite common and is better described as a syndrome with a heterogeneous presentation than as a single disease. Although most individuals can be effectively managed using a guideline-directed approach to care, those with the most severe illness may benefit from a more targeted therapy. The review describes our current understanding of how asthma phenotypes (observable characteristics) and endotypes (specific biologic mechanisms) can be employed to gain insight into asthma pathobiology and personalized therapy.

RECENT FINDINGS

Our understanding of the heterogeneity of asthma is increasing. The concept of asthma phenotype has become more complex, incorporating both clinical and biologic features. Several asthma endotypes (e.g., allergic bronchopulmonary mycosis, aspirin-exacerbated respiratory disease, severe late-onset hypereosinophilic asthma, etc.) have been proposed, but further research is needed to delineate specific mechanisms underlying asthma pathogenesis. Several biologic therapies targeting certain phenotypes are in development and are expected to broaden our armamentarium for treatment of severe asthma.

SUMMARY

Asthma is a heterogeneous condition with diverse characteristics and biologic mechanisms. Severe asthma is associated with significant morbidity and even mortality and represents a major unmet need. Stratification of asthma subtypes into phenotypes and endotypes should move the field forward in terms of more effective and personalized treatment.