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Innate lymphoid cells and asthma

The recent discovery of innate lymphoid cells (ILCs) has changed our understanding of immune regulation and uncovers the importance of innate immunity in the development of asthma. Historically, asthma was thought to be a Th2 mediated disease of the adaptive immune system but it has recently become clear that there are several different phenotypes of asthma some of which are non-allergic. In their review, Yu et al discuss the various roles of ILCs in the immune system specific to different asthma phenotypes and other allergic diseases ( J Allergy Clin Immunol 2014; 133(4): 943-950 ). ILCs are lymphocytes that produce a variety of cytokines similar to CD4+ T cells, but are antigen non-specific, which allows them to function independently of adaptive immunity.  The authors explain that ILC1s are similar to Th1 cells and have been shown to inhibit eosinophilic airway inflammation by promoting eosinophil apoptosis. Several studies show the likeness of ILC2s to Th2 cells in that they pr...

Recommendations for live viral and bacterial vaccines in immunodeficient patients and their close contacts

Live vaccines and the growing neglect of adherence to routine immunizations can be life-threatening to immunodeficient patients.  This prompted the Medical Advisory Committee of the Immune Deficiency Foundation to issue recommendations based on the literature and the collective experience of the committee members. Shearer et al describe the relative risk for a child with severe immunodeficiency from close-contact spread of infectious diseases that are vaccine-preventable or from the shedding of live virus or bacteria from individuals who have received a live vaccine ( J Allergy Clin Immunol 2014; 133(4): 961-966 ) .   The risk of acquiring an infection is well known to immediate family members of an immunodeficient child. However, relatives and non-family members who have not been vaccinated or have been vaccinated with live virus or bacteria pose a serious threat to these patients. Complacency is prevalent in society regarding pertussis, measles, mumps, and rubella vacci...

Host-microbial interactions in patients with chronic rhinosinusitis

The initiation and perpetuation of chronic rhinosinusitis (CRS) is known to be associated with host-microbial interactions.   Many studies have investigated these interactions with CRS in order to understand the mechanisms of the disease and provide better treatment options.   Dr. Hamilos summarizes the knowledge of host-microbial interactions in regards to normal sinus physiology and pathology, patients with CRS with and without polyps, and allergic fungal rhinosinusitis (AFRS) ( J Allergy Clin Immunol 2014; 133(3): 640-653 ).   Much of the research on the subject of CRS has been on bacterial infection and potential defects in innate immunity that might predispose patients to sinus infections.   Of CRS patients undergoing surgical intervention, more than 50% have bacterial biofilm in their diseased sinus tissues.     Biofilm is an important survival mechanism of bacteria allowing for attachment to surfaces.   The biofilm has been described to have an ...

Genetic analysis of asthma distinguishes subphenotypes

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About 50% of asthmatics that are genetically screened have T helper type 2 (Th2)-driven inflammation that is characterized by improved symptoms with inhaled corticosteroid response, higher IgE levels, and higher peripheral blood eosinophils.   While this genetic profiling is highly valuable by elucidating the pathogenesis of asthma and tailoring individual treatment regimens, bronchial airway epithelium brushings are invasive which limits its application to childhood asthma research.   This realization led Poole et al to determine if less invasive nasal airway epithelium brushings can proxy expression changes seen in the bronchial airway transcriptome in children with asthma ( J Allergy Clin Immunol 2014, 133(3): 670-678 ) .  In a cohort of Puerto Rican children, the authors used whole transcriptome RNA sequencing (RNA-seq) on nasal airway brushings from 10 controls and 10 subjects with asthma and targeted RNA-seq on 50 asthmatics and 50 controls to profile 105 genes. Th...

Peanut oral immunotherapy increases Tregs and epigenetically modifies FOXP3

The mechanisms contributing to clinical immune tolerance are largely unknown. The objective of Syed et al was to study the changes associated with clinical immune tolerance in antigen induced T cells, basophils, and antibodies in subjects undergoing oral immunotherapy (OIT) for peanut allergy ( J Allergy Clin Immunol 2014; 133(2): 500-510 ). The induction of regulatory T (Treg) cells has been a potential mechanism of maintaining immune tolerance, with Treg deficiencies implicated in the development of allergies.  Fork head box protein 3 (Foxp3) is a transcription factor that regulates Tregs, including natural regulatory Tregs (nTregs) and induced regulatory Tregs (iTregs). Epigenetic modifications to regions within the Foxp3 locus have been associated with stable Foxp3 expression and Treg cell-suppressive function.   The authors investigated whether antigen-induced Tregs (aiTregs) and humoral and basophil immune markers are induced by OIT in clinically immune tolerant (IT...

Food allergy: clinical advances and updates

The prevalence of food allergy is on the rise with up to 10% of the population afflicted, though remarkable advances have occurred in understanding and managing food allergies.  In their review article, Sicherer and Sampson focus on advances and updates in epidemiology, pathogenesis, diagnosis and treatment of food allergy ( J Allergy Clin Immunol 2014; 133(2): 291-307 ).  They explain that numerous genetic and environmental risk factors have been identified, with rectifiable risk factors such as vitamin D insufficiency, excess dietary fat, obesity, increased hygiene and timing of exposure to foods as being potential targets to address in prevention for the future.  Interesting clinical insights on route of sensitization, allergen characterization and immune response provide guidance for diagnosis and treatment. Allergen avoidance and emergency treatment remain the current management option for patients, although numerous clinical trials are underway for more definitive t...

Insights provided by mouse models relating to food allergy

Food allergy is a growing public health concern due to its increasing prevalence and life threatening potential.  Mouse models of food allergy have become useful tools for identifying the mechanisms involved in the sensitization of food allergens which are normally harmless as well as delineating the critical immune components of the effector phase of allergic reactions to food. In their review, Oyoshi et al have summarized the importance of animal models in food allergy research contrary to concerns regarding the relevance murine models have in understanding human disease ( J Allergy Clin Immunol 2014; 133(2): 309-317 ).  Mouse models have been exceedingly useful in the study of atopic dermatitis (AD) and asthma, paving the way for food allergy research.  For example, allergic sensitization or tolerance can be induced to specific allergens under controlled environmental conditions within defined genetic backgrounds that cannot be matched in human studies. The importance ...