Mas-related G protein-coupled receptor MRGPRX2 in human basophils: Expression and functional studies

BackgroundOccupancy of MRGPRX2 heralds a new era in our understandings of immediate drug hypersensitivity reactions (IDHRs), but a constitutive expression of this receptor by basophils is debated.ObjectiveTo explore the expression and functionality of MRGPRX2 in and on basophils.MethodsBasophils from patients with birch pollen allergy, IDHRs to moxifloxacin, and healthy controls were studied in different conditions, that is, in rest, after stimulation with anti-IgE, recombinant major birch pollen allergen (rBet v 1), moxifloxacin, fMLP, substance P (SP), or other potential basophil secretagogues. In a separate set of experiments, basophils were studied after purification and resuspension in different media.ResultsResting whole blood basophils barely express MRGPRX2 on their surface and are unresponsive to SP or moxifloxacin. However, surface MRGPRX2 is quickly upregulated upon incubation with anti-IgE or fMLP. Pre-stimulation with anti-IgE can induce a synergic effect on basophil degranulation in IgE-responsive subjects after incubation with SP or moxifloxacin, provided that basophils have been obtained from patients who experienced an IDHR to moxifloxacin. Cell purification can trigger a “spontaneous” and functional upregulation of MRGPRX2 on basophils, not seen in whole blood cells, and its surface density can be influenced by distinct culture media.ConclusionBasophils barely express MRGPRX2 in resting conditions. However, the receptor can be quickly upregulated after stimulation with anti-IgE, fMLP, or after purification, making cells responsive to MRGPRX2 occupation. We anticipate that such “conditioned” basophils constitute a model to explore MRGPRX2 agonism or antagonism, including IDHRs originating from the occupation of this receptor

Distinguishing Asthma Phenotypes Using Machine Learning Approaches.

Asthma is not a single disease, but an umbrella term for a number of distinct diseases, each of which are caused by a distinct underlying pathophysiological mechanism. These discrete disease entities are often labelled as asthma endotypes. The discovery of different asthma subtypes has moved from subjective approaches in which putative phenotypes are assigned by experts to data-driven ones which incorporate machine learning. This review focuses on the methodological developments of one such machine learning technique-latent class analysis-and how it has contributed to distinguishing asthma and wheezing subtypes in childhood. It also gives a clinical perspective, presenting the findings of studies from the past 5 years that used this approach. The identification of true asthma endotypes may be a crucial step towards understanding their distinct pathophysiological mechanisms, which could ultimately lead to more precise prevention strategies, identification of novel therapeutic targets and the development of effective personalized therapies

Standard methods for Apis mellifera venom research

Honey bees have a sting which allows them to inject venomous substances into the body of an opponent or attacker. As the sting originates from a modified ovipositor, it only occurs in the female insect, and this is a defining feature of the bee species that belong to a subclade of the Hymenoptera called Aculeata. There is considerable interest in bee venom research, primarily because of an important subset of the human population who will develop a sometimes life threatening allergic response after a bee sting. However, the use of honey bee venom goes much further, with alleged healing properties in ancient therapies and recent research. The present paper aims to standardize selected methods for honey bee venom research. It covers different methods of venom collection, characterization and storage. Much attention was also addressed to the determination of the biological activity of the venom and its use in the context of biomedical research, more specifically venom allergy. Finally, the procedure for the assignment of new venom allergens has been presented. Las abejas meliferas tienen un aguijon que les permite inyectar sustancias venenosas en el cuerpo de un oponente o atacante. El aguijon es un ovipositor modificado que solo se manifiesta en el insecto hembra, siendo este una caracteristica que define a las especies de abejas que pertenecen al subclado de himenopteros llamada Aculeata. Hay un interes considerable en la investigacion del veneno de abeja, principalmente debido a que un porcentaje importante de la poblacion humana desarrollara una respuesta alergica - a veces mortal - a la picadura de abeja. Sin embargo, el uso del veneno de la abeja melifera abarca mucho mas, con presuntas propiedades curativas en terapias antiguas e investigaciones recientes. El presente trabajo tiene como objetivo estandarizar metodos seleccionados para la investigacion del veneno de las abejas meliferas. Cubre diferentes metodos de recoleccion, caracterizacion y almacenamiento de veneno. Tambien se presto mucha atencion a la determinacion de la actividad biologica del veneno y su uso en el contexto de la investigacion biomedica, mas especificamente la alergia al veneno. Finalmente, se ha presentado el procedimiento para la asignacion de nuevos alergenos de veneno

Determinants in early life for asthma development

A reliable screening test in newborns for the subsequent development of bronchial asthma (BA) has not been found yet. This is mainly due to the complexity of BA, being made up by different types and underlying mechanisms. In different studies, a number of risk factors for BA have been identified. These include a positive family history of BA, passive smoking (also during pregnancy), prematurity (including pulmonary infections, RDS and BPD), early viral respiratory infections (such as RSV-bronchiolitis), male gender, early lung function abnormalities and atopic constitution. The major risk factor for persistent BA is an underlying allergic constitution. Therefore, early symptoms and markers of allergy (i.e. The Allergic March) and a positive family history for allergy should be considered as important risk factors for the development of BA

Elucidation of pathways driving asthma pathogenesis: development of a systems-level analytic strategy.

Asthma is a genetically complex, chronic lung disease defined clinically as episodic airflow limitation and breathlessness that is at least partially reversible, either spontaneously or in response to therapy. Whereas asthma was rare in the late 1800s and early 1900s, the marked increase in its incidence and prevalence since the 1960s points to substantial gene × environment interactions occurring over a period of years, but these interactions are very poorly understood (1-6). It is widely believed that the majority of asthma begins during childhood and manifests first as intermittent wheeze. However, wheeze is also very common in infancy and only a subset of wheezy children progress to persistent asthma for reasons that are largely obscure. Here, we review the current literature regarding causal pathways leading to early asthma development and chronicity. Given the complex interactions of many risk factors over time eventually leading to apparently multiple asthma phenotypes, we suggest that deeply phenotyped cohort studies combined with sophisticated network models will be required to derive the next generation of biological and clinical insights in asthma pathogenesis

Dendritic cell reconstitution is associated with relapse-free survival and acute GVHD severity in children after allogeneic stem cell transplantation

DCs are potent APCs and key regulators of innate and adaptive immunity. After allo-SCT, their reconstitution in the peripheral blood (PB) to levels similar to those in healthy individuals tends to be slow. We investigate the age- and sex-dependant immune reconstitution of myeloid (mDC) and plasmacytoid DC (pDC) in the PB of 45 children with leukaemia or myelodysplastic syndrome (aged 1-17 years, median 10) after allo-SCT with regard to relapse, acute GVHD (aGVHD) and relapse-free survival. Low pDC/μL PB up to day 60 post SCT are associated with higher incidence of moderate or severe aGVHD (P=0.035), whereas high pDC/μL PB up to day 60 are associated with higher risk of relapse (P<0.001). The time-trend of DCs/μL PB for days 0-200 is a significant predictor of relapse-free survival for both mDCs (P<0.001) and pDCs (P=0.020). Jointly modelling DC reconstitution and complications improves on these simple criteria. Compared with BM, PBSC transplants tend to show slower mDC/pDC reconstitution (P=0.001, 0.031, respectively), but have no direct effect on relapse-free survival. These results suggest an important role for both mDCs and pDCs in the reconstituting immune system. The inclusion of mDCs and pDCs may improve existing models for complication prediction following allo-SCT