Journal of Allergy and Clinical Immunology最新文献

Background: Overt immune activation by viral infections can lead to cytokine storm syndromes, such as hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS).

Objective: We aim to compare the immune response to different viral pathogens to understand the connection between infections and cytokine storm syndromes.

Methods: We recruited children who presented to the emergency room with fever for ≥ 3 days. We performed immune profiling using Olink proximity extension assay and flow cytometry. We compared the findings with cases of HLH, MAS, Kawasaki disease (KD), and multisystem inflammatory syndrome in children (MIS-C).

Results: We enrolled 352 febrile patients and studied 110 cases with confirmed common viral infections. We found that Epstein-Barr virus (EBV) uniquely triggered high levels of multiple cytokines (IL-18, IL-27, tumor necrosis factor, FLT3 ligand, and lymphotoxin alpha) and IFN-γ-induced chemokines (CXCL9/10/11 and CCL19). These patterns are similar to the hyperinflammatory response associated with HLH / MAS, but less consistent with the findings in KD and MIS-C. Flow cytometry analysis revealed that CD38⁺HLA-DR⁺ T lymphocytes, which are pathogenic cells responsible for IFN-γ production in HLH / MAS, are vastly expanded in patients with acute EBV infection. Cell sorting identified CD38⁺HLA-DR⁺ T cells as atypical lymphocytes that are classically associated with acute EBV infection.

Conclusion: This work broadens our understanding of common viral infections in children and provides an immunologic basis for the link between EBV infection and HLH / MAS.

Background: CD4⁺ T cells play essential roles in adaptive immunity. Distinct CD4⁺ T-cell subsets-T_H1, T_H2, T_H17, T_H22, T follicular helper, and regulatory T cells-have been identified, and their contributions to host defense and immune regulation are increasingly well defined. IL-9-producing T_H9 cells were first described in 2008 and appear to play both protective and pathogenic roles in human immunity. However, key requirements for generating human T_H9 cells remain incompletely defined.

Objective: We sought to define signaling pathways that regulate IL-9 production by human CD4⁺ T cells.

Methods: Human naive and memory CD4⁺ T cells were cultured under different conditions, and the molecular mechanisms regulating IL-9 induction were determined by assessing the ability of CD4⁺ T cells from a broad range of patients (n = 92) with pathogenic variants in key immune genes (n = 21) to differentiate into IL-9⁺ cells.

Results: We identified 2 culture conditions that yielded IL-9-expressing cells from naive CD4⁺ T cells and amplified IL-9 production by in vivo-generated memory CD4⁺ T cells: TGF-β plus IL-4 (ie, T_H9 polarizing condition), and the combination of IL-21, IL-23, IL-6, IL-1β, and TGF-β (ie, T_H17 polarizing condition). Combining these conditions had a synergistic effect in generating IL-9⁺CD4⁺ T cells. IL-9 induction required STAT3-activating cytokines as well as intact signaling via the T-cell receptor and STAT5. Importantly, IL-9 induction was restrained by IFN-γ/STAT1 and IL-10.

Conclusions: Our findings revealed critical molecules involved in inducing/restraining IL-9 production by human CD4⁺ T cells, thereby identifying pathways that could be targeted to modulate IL-9 in health and disease.

Background: Pathologic tissue remodeling with scarring and tissue rigidity has been demonstrated in inflammatory, autoimmune, and allergic diseases. Eosinophilic esophagitis (EoE) is an allergic disease that is diagnosed and managed by repeated biopsy procurement, allowing an understanding of tissue fibroblast dysfunction. While EoE associated tissue remodeling causes clinical dysphagia, food impactions and esophageal rigidity and strictures, molecular mechanisms driving these complications remain under investigation.

Objective: We hypothesized that chronic EoE inflammation induces pathogenic fibroblasts with dysfunctional tissue regeneration and motility.

Methods: We used single cell RNA sequence (scRNA-Seq), fluorescence activated cell sorting analysis, and fibroblast differentiation and migration assays to decipher the induced and retained pathogenic dysfunctions in EoE versus healthy esophageal fibroblasts.

Results: Differentiation assays demonstrated that active EoE fibroblasts retain regenerative programs for rigid cells such as chondrocytes (p<0.05) but lose healthy fibroblast capacity for soft cells such as adipocytes (p<0.01) which was reflected in biopsy immunostaining (p<0.01). EoE, but not healthy, fibroblasts have pro-inflammatory and pro-rigidity transcriptional programs on scRNA-Seq. In vivo, regenerative fibroblasts reside in perivascular regions and near the epithelial junction and, during EoE, have significantly increased migration (p<0.01). Flow analysis and functional assays demonstrated that regenerative EoE fibroblasts have decreased surface CD73 expression and activity (both p<0.05) compared to healthy, indicating aberrant ATP handling. EoE fibroblast dysfunctions were induced in healthy fibroblasts by reducing CD73 activity and rescued in EoE using adenosine repletion.

Conclusion: A normalization of perturbed extracellular ATP handling and CD73 could improve pathogenic fibroblast dysfunction and tissue regeneration in type 2 inflammatory diseases.

Aerosolized particles with a biological origin are called bioaerosols. Bioaerosols from plants, animals, fungi, bacteria, and viruses are an important class of environmental exposures that are clinically relevant to asthma. However, there are important differences in the pathways by which various bioaerosols affect asthma. Additionally, differences in individual susceptibility to different bioaerosols affect exposure reduction and mitigation strategies. Strategies to reduce exposures to potential triggers of asthma are routinely considered as part of standard clinical care and asthma management guidelines. Ventilation standards in buildings may reduce bioaerosol exposure for everyone, but they are not necessarily designed specifically to protect patients with asthma. Direct measurement of a bioaerosol is not generally necessary for practical applications where the relevant source of the bioaerosol has been identified. Different types of bioaerosols can be controlled with similar strategies that prioritize source control (eg, reducing resuspension, integrated pest management, controlling moisture), and these can be supplemented by enhancing air filtration. The goal of this review is to summarize the latest information on bioaerosols, including allergens, fungi, bacteria, and viruses, that have been associated with adverse asthma outcomes and to discuss mitigation options.

Background: Airway hyperresponsiveness (AHR) is a hallmark of persistent asthma. However, effects of IL-4/13 blockade with dupilumab (Dupi) on AHR are unknown.

Objectives: This study sought to investigate the effect of 12 weeks of Dupi on AHR, asthma control, and quality of life.

Methods: After a 4-week run-in on beclomethasone/formoterol maintenance and reliever therapy (baseline), participants with uncontrolled type-2 high severe asthma received open-label Dupi 300 mg twice weekly, for 12 weeks. Mannitol challenges were done at baseline, 2, 4, and 12 weeks and following a 12-week washout. Study power was 90% to detect 1 doubling difference (dd) in mannitol PD₁₀ FEV₁ threshold at week 12.

Results: Of 24 enrolled patients, 23 completed per protocol mannitol AHR at 12 weeks. Mean baseline values were age 52 years, FEV₁ 82%, Asthma Control Questionnaire 2.53, mini-Asthma Quality of Life Questionnaire 3.84, inhaled corticosteroids dose 1300 μg; fractional exhaled nitric oxide 50 parts per billion; Eosinophils 552 cells/μL. Mannitol sensitivity as PD₁₀ was significantly attenuated by week 4, and reactivity as response dose ratio by week 2. After 12 weeks of Dupi, mean dd for PD₁₀ was 1.78 (95% CI: 1.23-2.33; P < .001) and for response dose ratio was 3.40 (95% CI: 2.25-4.55; P < .001). At week 12, Asthma Control Questionnaire improved by 1.73 (95% CI: 1.11-2.36; P < .001); mini-Asthma Quality of Life Questionnaire by 2.31 (95% CI: 1.57-3.05; P < .001); FEV₁ by 0.39 L (95% CI: 0.11-0.67; P < .01); and PEF by 61 L/min (95% CI: 24-98; P < .001). Beclomethasone/formoterol maintenance and reliever therapy requirement was reduced at 12 weeks versus baseline by 1.7 puffs/d (95% CI: 0.7-2.7; P < .01). After washout at week 24, the dd change was 0.96 (95% CI: 0.02-1.91; P < .05).

Conclusions: Dupilumab attenuated mannitol AHR to a clinically relevant degree despite concomitant inhaled corticosteroid reduction, combined with improvements in lung function, asthma control, and quality of life.

Laboratory-based immunology evaluation is essential to the diagnostic workup of patients with complex immune disorders, and is as essential, if not more so, depending on the context, as genetic testing, because it enables identification of aberrant pathways amenable to therapeutic intervention and clarifies variants of uncertain significance. There have been considerable advances in techniques and instrumentation in the clinical laboratory in the past 2 decades, although there are still "miles to go." One of the goals of the clinical laboratory is to ensure advanced diagnostic testing is widely accessible to physicians and thus patients, through reference laboratories, particularly in the context of academic medical centers. This ensures a greater likelihood of translating research discoveries into the diagnostic laboratory, on the basis of patient care needs rather than a sole emphasis on commercial utility. However, these advances are under threat from burdensome regulatory oversight that can compromise, at best, and curtail, at worst, the ability to rapidly diagnose rare immune disorders and ensure delivery of precision medicine. This review discusses the clinical utility of diagnostic immunology tools, beyond cellular immunophenotyping of lymphocyte subsets, which can be used in conjunction with clinical and other laboratory data for diagnosis as well as monitoring of therapeutic response in patients with genetic immunologic diseases.

Background: Exposure to fungi, especially Aspergillus fumigatus, can elicit potent allergic inflammation that triggers and worsens asthmatic disease. Dendritic cells (DCs) initiate allergic inflammatory responses to allergic stimuli. However, it is unclear if Af spores during isotropic growth (early spore swelling) can activate DCs to initiate allergic responses or if germination is required. This lack of basic understanding of how Af causes disease is a barrier to developing new treatments.

Objective: We sought to show that a precise Af morphotype stage during spore swelling can trigger DCs to mediate allergic inflammatory responses and ascertain if antifungal therapeutics can be effective at suppressing this process.

Methods: We used an Af strain deficient in pyrimidine biosynthesis (ΔpyrG) to generate populations of Af spores arrested at different stages of isotropic growth (swelling) via temporal removal of uracil and uridine from growth media. These arrested spore stages were cultured with bone marrow-derived DCs (BMDCs), and their activation was measured via flow cytometry and ELISA to examine which growth stage was able to activate BMDCs. These BMDCs were then adoptively transferred into the airways to assess if they were able to mediate allergic inflammation in naïve recipient mice. Allergic airway inflammation in vivo was determined via flow cytometry, ELISA, and real-time quantitative PCR. This system was also used to determine if antifungal drug (itraconazole) treatment could alter early stages of spore swelling and therefore BMDC activation and in vivo allergic inflammation upon adoptive transfer.

Results: We found that Af isotropic growth is essential to trigger BMDC activation and mediate allergic airway inflammation. Furthermore, using time-arrested Af stages, we found that at least 3 hours in growth media enabled spores to swell sufficiently to activate BMDCs to elicit allergic airway inflammation in vivo. Incubation of germinating Af with itraconazole reduced spore swelling and partially reduced their ability to activate BMDCs to elicit in vivo allergic airway inflammation.

Conclusion: Our results have pinpointed the precise stage of Af development when germinating spores are able to activate DCs to mediate downstream allergic airway inflammation. Furthermore, we have identified that antifungal therapeutics partially reduced the potential of Af spores to stimulate allergic responses, highlighting a potential mechanism by which antifungal treatment might help prevent the development of fungal allergy.

The major challenge in allergy diagnosis is development of accessible and reliable diagnostics that can predict the clinical outcome following exposure to culprit allergen(s) or cross-reactive molecules and identification of safer alternatives than the current state-of-the-art methods. There is accumulating evidence that flow-based analyses for the quantification of activated basophils and mast cells subsequent to in vitro challenge (the basophil and mast cell activation test [BAT/MAT] or basophil activation test [BAT] and mast cell activation test [MAT]) could meet the diagnostic requirements for IgE-dependent allergies, drug hypersensitivities, and subsets of autoimmune urticaria. Furthermore, the BAT and MAT have found application in research and other nondiagnostic fields. However, appropriate use of the BAT and MAT requires understanding of the diversity of the source materials used and degranulation metrics to ensure correct test performance and interpretation of results. In this review, we provide the main applications and limitations of the BAT and MAT, as performed thus far.