The impact of obesity on immune function in pediatric asthma

Impact of steroids on the immune profiles of children with asthma living in the inner-city

Background: Inner-city asthma is associated with high morbidity and systemic steroid use. Chronic steroid use impacts immune function; however, there is a lack of data with regard to the extent of immunosuppression in patients with asthma and who are receiving frequent systemic steroids. Objective: To identify the impact of frequent systemic steroid bursts on the immune function of children with asthma who live in the inner city. Methods: Children ages 3-18 years with asthma were divided into study (≥2 systemic steroid bursts/year) and control groups (0-1 systemic steroid bursts/year). Lymphocyte subsets; mitogen proliferation assay; total immunoglobulin G (IgG) value, and pneumococcal and diphtheria/tetanus IgG values were evaluated. Results: Ninety-one participants were enrolled (study group [n = 42] and control group [n = 49]). There was no difference in adequate pneumococcal IgG value, diphtheria/tetanus IgG value, mitogen proliferation assays, lymphocyte subsets, and IgG values between the two groups. Children who received ≥2 steroid bursts/year had a significantly lower median pneumococcal IgG serotype 7F value. Most of the immune laboratory results were normal except for the pneumococcal IgG value. Most of the participants (n/N = 72/91 [79%]) had an inadequate pneumococcal IgG level (<7/14 serotypes ≥1.3 µg/mL). The participants with inadequate pneumococcal IgG level and who received a pneumococcal polysaccharide vaccine 23 (PPSV23) boost had a robust response. There was no significant difference in infection, steroid exposure, asthma severity, or morbidities between those with adequate versus inadequate pneumococcal IgG values. Conclusion: Children with asthma who live in the inner city and receive ≥2 steroid bursts/year do not have a significantly different immune profile from those who receive ≤1 steroid bursts/year do not have a significantly different immune profile from those who do not. Although appropriately vaccinated, most participants had an inadequate pneumococcal IgG level, regardless of steroid exposure and asthma severity. These children may benefit from PPSV23.

Leveraging Systems Immunology to Optimize Diagnosis and Treatment of Inborn Errors of Immunity

Inborn errors of immunity (IEI) are monogenic disorders that can cause diverse symptoms, including recurrent infections, autoimmunity and malignancy. While many factors have contributed, the increased availability of next-generation sequencing has been central in the remarkable increase in identification of novel monogenic IEI over the past years. Throughout this phase of disease discovery, it has also become evident that a given gene variant does not always yield a consistent phenotype, while variants in seemingly disparate genes can lead to similar clinical presentations. Thus, it is increasingly clear that the clinical phenotype of an IEI patient is not defined by genetics alone, but is also impacted by a myriad of factors. Accordingly, we need methods to amplify our current diagnostic algorithms to better understand mechanisms underlying the variability in our patients and to optimize treatment. In this review, we will explore how systems immunology can contribute to optimizing both diagnosis and treatment of IEI patients by focusing on identifying and quantifying key dysregulated pathways. To improve mechanistic understanding in IEI we must deeply evaluate our rare IEI patients using multimodal strategies, allowing both the quantification of altered immune cell subsets and their functional evaluation. By studying representative controls and patients, we can identify causative pathways underlying immune cell dysfunction and move towards functional diagnosis. Attaining this deeper understanding of IEI will require a stepwise strategy. First, we need to broadly apply these methods to IEI patients to identify patterns of dysfunction. Next, using multimodal data analysis, we can identify key dysregulated pathways. Then, we must develop a core group of simple, effective functional tests that target those pathways to increase efficiency of initial diagnostic investigations, provide evidence for therapeutic selection and contribute to the mechanistic evaluation of genetic results. This core group of simple, effective functional tests, targeting key pathways, can then be equitably provided to our rare patients. Systems biology is thus poised to reframe IEI diagnosis and therapy, fostering research today that will provide streamlined diagnosis and treatment choices for our rare and complex patients in the future, as well as providing a better understanding of basic immunology.

Differential gene expression in nasal airway epithelium from overweight or obese youth with asthma

BACKGROUND

The mechanisms underlying the known link between overweight/obesity and childhood asthma are unclear. We aimed to identify differentially expressed genes and pathways associated with obesity-related asthma through a transcriptomic analysis of nasal airway epithelium.

METHODS

We compared the whole transcriptome in nasal airway epithelium of youth with overweight or obesity and asthma with that of youth of normal weight and asthma, using RNA sequencing data from a cohort of 235 Puerto Ricans aged 9-20 years (EVA-PR) and an independent cohort of 66 children aged 6-16 years in Pittsburgh (VDKA). Differential expression analysis adjusting for age, sex, sequencing plate number, and sample sorting protocol, and the first five principal components were performed independently in each cohort. Results from the two cohorts were combined in a transcriptome-wide meta-analysis. Gene enrichment and network analyses were performed on top genes.

RESULTS

In the meta-analysis, 29 genes were associated with obesity-related asthma at an FDR-adjusted p <.05, including pro-inflammatory genes known to be differentially expressed in adipose tissue of obese subjects (e.g., CXCL11, CXCL10, and CXCL9) and several novel genes. Functional enrichment analyses showed that pathways for interferon signaling, and innate and adaptive immune responses were down-regulated in overweight/obese youth with asthma, while pathways related to ciliary structure or function were up-regulated. Upstream regulatory analysis predicted significant inhibition of the IRF7 pathway. Network analyses identified "hub" genes like GBP5 and SOCS1.

CONCLUSION

Our transcriptome-wide analysis of nasal airway epithelium identified biologically plausible genes and pathways for obesity-related asthma in youth.

School Asthma Care During COVID-19: What We Have Learned and What We Are Learning

The focus of this article is to review school asthma care during coronavirus disease 2019 (COVID-19). Asthma is listed as a risk factor in some guidelines, although children with asthma appear to not be at increased risk of severe respiratory outcomes compared with children without asthma during the pandemic. Differentiating COVID-19 from allergic disease is very difficult in the school-aged children. For school management, there is firm evidence that masks do not exacerbate underlying lung conditions including asthma, and evidence to date supports that children with asthma can learn in-person at school because they do not appear to be at increased risk of COVID-19 morbidity or mortality. For children and adolescents, the COVID-19 vaccine has been demonstrated to be safe and well tolerated. School asthma management includes remaining on prescribed asthma medications. Asthma management, as with management of all pediatric conditions, must also factor in the impact of adverse social determinants and health disparities. Broadly, the pandemic has also served as a call to resource stewardship and innovation and allowed practitioners to consider how this may impact asthma care moving forward.

Do not forget asthma comorbidities in pediatric severe asthma!

Asthma is the most common chronic respiratory disease in childhood. The long-term goals in managing asthma aim to control symptoms and prevent exacerbations, as well as to reduce side effects of therapy and mortality disease-related. Most of patients have mild to moderate asthma and respond well to standard therapies. However, a minor proportion of children with asthma has severe disease that remains uncontrolled despite optimal adherence to prescribed therapy and treatment of contributory factors, including trigger exposures and comorbidities, which can mimic or worsen asthma and contribute to exacerbations and poor quality of life. Evaluation of comorbidities is fundamental to optimize the management of the disease in a subgroup of patients with poor responder asthma. The overall aim of this article is to describe characteristics of main pediatric severe asthma comorbidities reported in literature, giving clinicians tools to recognize and manage properly these conditions.

Nutrition, Obesity and Asthma Inception in Children. The Role of Lung Function

Obesity is an important public health problem. WHO estimates that about 39 million children younger than 5 years of age are overweighted or obese. On the other hand, asthma is the most prevalent chronic disease in childhood, and thus, many children share those two conditions. In the present paper we review the epidemiology of children with asthma and obesity, as well as the consequences of being obese on the respiratory system. On the one hand obesity produces an underlying T-helper 2 (TH2) low inflammation state in which numerous cytokines, which could have an impact in the respiratory system play, a role. On the other hand, some respiratory changes have been described in obese children and, specially, the development of the so called “dysanapsis” (the disproportionate scaling of airway dimensions to lung volume) which seems to be common during the first stages of life, probably related to the early development of this condition. Finally, this review deals with the role of adipokines and insulin resistance in the inception and worsening of asthma in the obese child.