Allergology International最新文献

IgE antibodies raised against innocuous environmental antigens cause allergic diseases like allergic rhinitis, food allergy, and allergic asthma. While some allergies are often outgrown, others (peanut, shellfish, tree nut) are lifelong in the majority of individuals. Lifelong allergies are the result of persistent production of allergen-specific IgE. However, IgE antibodies and the plasma cells that secrete them tend to be short-lived. Persistent allergen-specific IgE titres are thought to be derived from the continued renewal of IgE plasma cells from memory B cells in response to allergen encounters. The initial generation of allergen-specific IgE is driven by B cell activation by IL-4 producing Tfh cells, but the cellular and molecular mechanisms of the long-term production of IgE are poorly characterized. This review investigates the mechanisms governing IgE production and Tfh activation in the primary and recall responses, towards the objective of identifying molecular targets for therapeutic intervention that durably inactivate the IgE recall response.

Background: Basophils, despite being the least common granulocytes, play crucial roles in type 2 immune responses, such as chronic allergic inflammation and protective immunity against parasites. However, the molecular mechanisms regulating basophil activation and inflammatory molecule production remain poorly understood. Therefore, we investigated the role of RNA-binding proteins, specifically tristetraprolin (TTP), in regulating inflammatory molecule production in basophils.

Methods: Using antigen/IgE-stimulated basophils from wild-type (WT) and TTP-knockout (TTP-KO) mice, we performed bulk RNA sequencing, transcriptome-wide mRNA stability assays, and protein analyses. We also examined mRNA expression and protein production of inflammatory molecules in TTP-KO basophils under stimulation with IL-33 or LPS. Furthermore, we evaluated the in vivo significance of TTP in basophils using basophil-specific TTP-deficient mice and a hapten oxazolone-induced atopic dermatitis model.

Results: TTP expression was upregulated in basophils following stimulation with antigen/IgE, IL-33, or LPS. Under these stimuli, TTP-KO basophils exhibited elevated mRNA expression of inflammatory molecules, such as Il4, Areg, Ccl3, and Cxcl2, compared to WT basophils. Transcriptome-wide mRNA stability assays revealed that TTP deficiency prolonged the mRNA half-life of these inflammatory mediators. Notably, the production of these inflammatory proteins was significantly increased in TTP-KO basophils. Moreover, basophil-specific TTP-deficient mice showed exacerbated oxazolone-induced atopic dermatitis-like skin allergic inflammation.

Conclusions: TTP is a key regulator of basophil activation, controlling the production of inflammatory mediators through mRNA destabilization. Our in vivo findings demonstrate that the absence of TTP in basophils significantly aggravates allergic skin inflammation, highlighting its potential as a therapeutic target for allergic diseases.

Atopy is considered the epidemic of the 21st century, and while decades of research have established a direct link between Th2 cells driving pathogenic IgE-mediated allergic disease, only in the past years have T follicular helper (Tfh) cells emerged as pivotal drivers of these responses. In this review, we will examine the molecular mechanisms governing the IgE response, with a particular emphasis on the key cytokines and signaling pathways. We will discuss the exclusion of IgE-producing B cells from germinal centers and explore the recently established role of follicular T cell function and heterogeneity in driving or curtailing these immune responses. Additionally, we will assess the current state of major monoclonal antibodies and allergen immunotherapies designed to counteract Th2-driven inflammation, as well as reflect on the need to investigate how these biologics impact Tfh cell activity, differentiation, and function, as these insights could pave the way for much-needed therapeutic innovation in the treatment of allergic diseases.

Background: Precise skin phenotypic data are indispensable in accurately diagnosing atopic dermatitis (AD). Therefore, this study examined the interobserver concordance for AD and non-AD diagnoses between two dermatologists. AD prevalence determined by the self-reported physician diagnoses and the diagnoses determined from the United Kingdom (UK) diagnostic criteria were compared with the diagnoses made by the two dermatologists, using data from a skin health survey.

Methods: This study included 1,638 children that participated in the skin health survey, which was part of the Tohoku Medical Megabank Project Birth and Three-Generation Cohort Study. AD was assessed using dermatologist assessments, self-reported physician diagnoses, and the UK diagnostic criteria. The concordance for diagnoses was evaluated using kappa. The sensitivity and specificity of the self-reported physician diagnoses and the UK diagnostic criteria were calculated by comparing them with the two dermatologists' diagnoses.

Results: Among the 1,638 children, 393 (24.0 %), 194 (11.9 %), and 597 (37.2 %) were diagnosed with AD by the two dermatologists, physicians, and the UK diagnostic criteria, respectively. The kappa (95 % CI) of the interobserver concordance for AD or non-AD diagnoses between the two dermatologists was 0.78 (0.75-0.81). The sensitivity and specificity of the self-reported physician diagnoses were 26.7 % and 94.1 %, respectively. The sensitivity and specificity of the UK diagnostic criteria were 85.0 % and 82.4 %, respectively.

Conclusions: Interobserver concordance for AD or non-AD diagnoses between the two dermatologists was substantial. Self-reported physician diagnoses exhibited low sensitivity that potentially indicated underdiagnosis of AD, whereas the UK diagnostic criteria might overdiagnose AD.

Characteristic symptoms of NSAID-exacerbated respiratory disease (N-ERD) include asthma, chronic eosinophilic rhinosinusitis with nasal polyposis, cysteinyl LT (CysLT) overproduction and NSAIDs hypersensitivity. Some N-ERD patients present with episodic treatment-resistant extra-respiratory symptoms (CysLT-associated coronary artery vasospasm, gastroenteritis, or skin rash). Even when using standard treatments for respiratory and extra-respiratory symptoms, including systemic corticosteroids and aspirin desensitization, it is difficult to control the clinical symptoms and severe type 2 inflammation involved with mast cells, eosinophils, ILC2s, and platelet activation. Few treatment options are applicable in a clinical setting. Therefore, identifying effective treatments is essential for managing N-ERD patients who suffer from these conditions. Our previous observational study demonstrated 12-month omalizumab treatment of N-ERD was clinically effective against respiratory symptoms. Despite the remaining eosinophilia, omalizumab significantly reduced urinary LTE₄ and PGD₂ metabolites to near normal levels at steady state. Based on the preliminary study, we demonstrated that omalizumab induced tolerance to aspirin in N-ERD patients 3 months after therapy initiation and suppressed activation of mast cells during 24 h of initiation in a randomized manner. Moreover, omalizumab had significant efficacy against extra-respiratory symptoms at baseline (lacking aspirin exposure) as well as throughout aspirin challenge. This review addresses the latest discoveries related to N-ERD pathogenesis and the significant effectiveness of omalizumab on N-ERD as a mast cell stabilizer. Our findings regarding omalizumab-associated mast cell inhibitory effects are indirect evidence that mast cell dysregulation and, possibly, IgE are pivotal components of N-ERD.