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Genetic testing has become an integral component of the diagnostic evaluation of patients with suspected primary immunodeficiency diseases. Results of genetic testing can have a profound effect on clinical management decisions. Therefore clinical providers must demonstrate proficiency in interpreting genetic data. Because of the need for increased knowledge regarding this practice, the American Academy of Allergy, Asthma & Immunology Primary Immunodeficiency Diseases Committee established a work group that reviewed and summarized information concerning appropriate methods, tools, and resources for evaluating variants identified by genetic testing. Strengths and limitations of tests frequently ordered by clinicians were examined. Summary statements and tables were then developed to guide the interpretation process. Finally, the need for research and collaboration was emphasized. Greater understanding of these important concepts will improve the diagnosis and management of patients with suspected primary immunodeficiency diseases. [ABSTRACT FROM AUTHOR]

Background: Autosomal dominant hyper-IgE syndrome (AD-HIES) is caused by mutations in signal transducer and activator of transcription 3 (STAT3). We describe 2 subjects in whom somatic mosaicism was associated with intermediate phenotypes. Objective: Somatic mosaics might shed light on the pathogenesis of dominant STAT3 mutations and the mechanisms behind the immunologic and nonimmunologic features of the disease. Methods: Clinical evaluations were conducted. Mutant STAT3 was amplified from different tissues and sequenced, and the percentage of mosaicism in various cell types was calculated. Flow cytometry was performed to determine percentages of IL-17+ cells, IL-22+ cells, or both. Suction blisters were induced in 1 subject, and exudate fluid was analyzed for whether emigrating neutrophils were STAT3 mutant or wild-type; neutrophils from peripheral blood were simultaneously examined. Results: The 2 subjects with STAT3 somatic mosaicism had intermediate phenotypes and were found to have preserved TH17 cell compartments and apparently normal CD8 cells. However, they still had infections, including mucocutaneous candidiasis. The percentage of STAT3 mutant neutrophils migrating into blisters at 16 hours was the same as in peripheral blood, suggesting normal chemotaxis. Conclusion: STAT3 mosaicism accounts for a milder phenotype and allows for further investigation into the pathogenesis of AD-HIES. Despite having a preserved TH17 cell compartment, both subjects with mosaicism had chronic mucocutaneous candidiasis, suggesting that candidiasis in subjects with AD-HIES is not driven solely by low TH17 cell numbers. The percentage of STAT3 mutant neutrophils emigrating into a suction blister at 16 hours was the same as the percentage in peripheral blood, suggesting that early chemotaxis of STAT3 neutrophils is normal in vivo. [Copyright &y& Elsevier]

Asthma is a complex heterogeneous disease occurring in adults and children that is characterized by distinct inflammatory patterns. While numerous studies have been performed in adults, little is known regarding the heterogeneity of severe asthma in children, particularly inflammatory signatures involving the air spaces. We sought to determine the relationship of bronchoalveolar lavage (BAL) cytokine/chemokine expression patterns in children with severe therapy-resistant asthma stratified according to neutrophilic versus nonneutrophilic BAL inflammatory cell patterns. Children with severe asthma with inadequate symptom control despite therapy underwent diagnostic bronchoscopy and BAL. Inflammatory cytokine/chemokine concentrations were determined using a multiplex protein bead assay. Analysis of BAL constituents with an unbiased clustering approach revealed distinct cytokine/chemokine patterns, and these aligned with pathways associated with type 2 innate lymphoid cells, monocytes, neutrophil trafficking, and T effector cells. All cytokines examined (n = 27) with 1 exception (vascular endothelial growth factor) were overexpressed with BAL neutrophilia compared with nonneutrophilic asthma, and this was confirmed in a cross-validation analysis. Cytokines specifically responsible for T h 17 (IL-17, IL-6, G-CSF) and T h 1 differentiation and expression (IL-12, TNF-α, IFN-γ) were enhanced in the neutrophilic cohorts. Neutrophilic groups were also characterized by higher prevalence of bacterial and viral pathogens; however, cytokine expression patterns manifested independently of pathogen expression. The results demonstrate that children with refractory asthma and neutrophilic inflammation had a BAL cytokine pattern consistent with a mixed T h 17/T h 1/T h 2 response. In contrast, nonneutrophilic asthma presented independently of cytokine overexpression. [ABSTRACT FROM AUTHOR]

Background The pathogenesis of severe asthma in childhood remains poorly understood. Objective We sought to construct the immunologic landscape in the airways of children with severe asthma. Methods Comprehensive analysis of multiple cell types and mediators was performed by using flow cytometry and a multiplex assay with bronchoalveolar lavage (BAL) specimens (n = 68) from 52 highly characterized allergic and nonallergic children (0.5-17 years) with severe treatment-refractory asthma. Multiple relationships were tested by using linear mixed-effects modeling. Results Memory CCR5 + T H 1 cells were enriched in BAL fluid versus blood, and pathogenic respiratory viruses and bacteria were readily detected. IFN-γ + IL-17 + and IFN-γ − IL-17 + subsets constituted secondary T H types, and BAL fluid CD8 + T cells were almost exclusively IFN-γ + . The T H 17-associated mediators IL-23 and macrophage inflammatory protein 3α/CCL20 were highly expressed. Despite low T H 2 numbers, T H 2 cytokines were detected, and T H 2 skewing correlated with total IgE levels. Type 2 innate lymphoid cells and basophils were scarce in BAL fluid. Levels of IL-5, IL-33, and IL-28A/IFN-λ2 were increased in multisensitized children and correlated with IgE levels to dust mite, ryegrass, and fungi but not cat, ragweed, or food sources. Additionally, levels of IL-5, but no other cytokine, increased with age and correlated with eosinophil numbers in BAL fluid and blood. Both plasmacytoid and IgE + FcεRI + myeloid dendritic cells were present in BAL fluid. Conclusions The lower airways of children with severe asthma display a dominant T H 1 signature and atypical cytokine profiles that link to allergic status. Our findings deviate from established paradigms and warrant further assessment of the pathogenicity of T H 1 cells in patients with severe asthma. [ABSTRACT FROM AUTHOR]

We present results from clinical studies on plasma infusion done in the late 1970s in patients with hypogammaglobulinemia in which we documented the short half-life of both total and allergen-specific IgE in serum. The development of specific allergic sensitization in the skin of those patients followed by the gradual decrease in sensitization over 50 days was also documented. The data are included here along with a discussion of the existing literature about the half-life of IgE in both the circulation and skin. This rostrum reinterprets the earlier clinical studies in light of new insights and mechanisms that could explain the rapid removal of IgE from the circulation. These mechanisms have clinical implications that relate to the increasing use of anti-IgE mAbs for the treatment of allergic disease. [ABSTRACT FROM AUTHOR]

Background: Severe atopic conditions associated with elevated serum IgE are heterogeneous with few known causes. Nearly every patient with autosomal-dominant hyper-IgE syndrome (AD-HIES) due to signal transducer and activator of transcription 3 (STAT3) mutations has a history of eczematous dermatitis and elevated IgE; however, clinical atopy has never been systematically studied. Objective: Understanding of genetic determinants of allergic disease may lead to novel therapies in controlling allergic disease. Methods: We conducted clinical evaluation of the rates of food allergies and anaphylaxis in patients with AD-HIES, a cohort of patients with no STAT3 mutation but with similar histories of elevated IgE and atopic dermatitis, and healthy volunteers with no history of atopy. Morphine skin prick testing, ImmunoCAP assays for allergen-specific IgE, and basophil activation were measured. A model of systemic anaphylaxis was studied in transgenic mice carrying an AD-HIES mutation. STAT3 was silenced in LAD2 and primary human mast cells to study the role of STAT3 in signaling and degranulation after IgE cross-linking. Results: Food allergies and anaphylaxis were markedly diminished in patients with AD-HIES compared with a cohort of patients with no STAT3 mutation but with similar histories of elevated IgE and atopic dermatitis. Morphine skin prick testing and basophil activation were diminished in patients with AD-HIES, whereas mice carrying an AD-HIES mutation were hyporesponsive to systemic anaphylaxis models. Rapid mast cell STAT3 serine727 phosphorylation was noted after IgE cross-linking, and inhibition of STAT3 signaling in mast cells lead to impaired FcεRI-mediated proximal and distal signaling, as well as reduced degranulation. Conclusion: This study serves as an example for how mutations in specific atopic pathways can lead to discrete allergic phenotypes, encompassing increased risk of some phenotypes but a relative protection from others. [Copyright &y& Elsevier]

Background: Mutations in signal transducer and activator of transcription (STAT) 1 cause a broad spectrum of disease, ranging from severe viral and bacterial infections (amorphic alleles) to mild disseminated mycobacterial disease (hypomorphic alleles) to chronic mucocutaneous candidiasis (CMC; hypermorphic alleles). The hypermorphic mutations are also associated with arterial aneurysms, autoimmunity, and squamous cell cancers. Objective: We sought to investigate the role of STAT1 gain-of-function mutations in phenotypes other than CMC. Methods: We initially screened patients with CMC and autoimmunity for STAT1 mutations. We functionally characterized mutations in vitro and studied immune profiles and regulatory T (Treg) cells. After our initial case identifications, we explored 2 large cohorts of patients with wild-type forkhead box protein 3 and an immune dysregulation–polyendocrinopathy–enteropathy–X-linked (IPEX)–like phenotype for STAT1 mutations. Results: We identified 5 children with polyendocrinopathy, enteropathy, and dermatitis reminiscent of IPEX syndrome; all but 1 had a variety of mucosal and disseminated fungal infections. All patients lacked forkhead box protein 3 mutations but had uniallelic STAT1 mutations (c.629 G>T, p.R210I; c.1073 T>G, p.L358W, c.796G>A; p.V266I; c.1154C>T, T385M [2 patients]). STAT1 phosphorylation in response to IFN-γ, IL-6, and IL-21 was increased and prolonged. CD4+ IL-17–producing T-cell numbers were diminished. All patients had normal Treg cell percentages in the CD4+ T-cell compartment, and their function was intact in the 2 patients tested. Patients with cells available for study had normal levels of IL-2–induced STAT5 phosphorylation. Conclusions: Gain-of-function mutations in STAT1 can cause an IPEX-like phenotype with normal frequency and function of Treg cells. [Copyright &y& Elsevier]