Immunology and genetics of asthma, and probiotics in the treatment of atopic dermatitis

Immunology and genetics of asthma, and probiotics in the treatment of atopic dermatitisThis past year has been disrupting, but also seen positive challenges in many aspects.And we would like to start this first issue of 2021 with a positive message.COVID-19 vaccines are coming, and hopefully, they will largely contribute to controlling the spread of the pandemic.Common vaccines trigger an immune response by an antigen-driven stimulus.However, the SARS-CoV-2-induced pandemic control is addressed not only by classic vaccine strategies but also by new, RNA-based strategies.The first review of this issue by Eberhardt and Siegrist assesses the various immunization strategies and their limitations to the pediatric population. 1 In addition, with the second wave (or third wave for some regions) pediatricians will be faced with more patients suffering from the multisystem inflammatory syndrome in children (MIS-C).The second review also addresses COVID-19 in pediatrics and discusses potential explanations for progression from "classic" COVID-19 to MIS-C. 2Asthma is a common disease in childhood, with still unmet needs regarding the understanding of immune mechanisms of progressions, as well as optimization of treatment by immunomodulators. 3,4The first study I wish to comment on in this editorial is published by Beatriz Sastre and colleagues who investigated immune mechanisms underlying the development of recurrent wheezing after bronchiolitis in infancy. 5Cells obtained from nasopharyngeal aspirates were sorted by flow cytometry to isolate type 2 innate lymphoid cells (ILC2).Cell mRNA expression was analyzed for a variety of inflammatory factors, and a large panel of pro-inflammatory and immunomodulatory factors, as well as lipid mediators and nitrites, was evaluated by ELISA and Luminex.They observed a higher expression of the ST2 + IL-33 receptor in the ILC2 population from the bronchiolitis group.This expression receptor could be increased by the presence of IL-1β, IL-2, or lipid mediators such as cysteinyl leukotrienes (LTC4 or LTE4) or prostaglandin D2.They conclude by mentioning that bronchiolitis patients had a higher percentage of ILC2 cells in the nasal aspirate and that this population of cells, by providing specific inflammatory signals, could play a significant role in the development of wheezing episodes later in life.Other studies and a review have recently addressed cell-related mechanisms of asthma and confirm the recent interest in innate-immunity-related mechanisms of asthma.