A rational approach to the management of severe refractory asthma

A EUFOREA comment on a lost comorbidity of asthma

"Epidemiology of comorbidities and their association with asthma control" (Tomisa, G., Horváth, A., Sánta, B. et al. Epidemiology of comorbidities and their association with asthma control. Allergy Asthma Clin Immunol 17, 95 (2021). https://doi.org/10.1186/s13223-021-00598-3 ) is an interesting paper reflecting data collection from more than 12,000 asthmatic patients in Hungary regarding their condition and associated comorbidities. We found it valuable that the paper provides an overview of asthma comorbidities not usually considered in similar reports. Nevertheless, we believe that chronic rhinosinusitis (CRS) with or without nasal polyps (CRSwNP or CRSsNP) should have been listed due to its high incidence and prevalence, its association with asthma which is also endorsed in both GINA and EPOS, as well as in several peer-reviewed scientific papers, and to reflect the role of this comorbidity in poor control and a most severe presentation of asthma for the patient. Consequently, several targeted therapies (especially monoclonal antibodies) used for several years in severe forms of asthma are now indicated also for the effective treatment of nasal polyps.

A rare case of refractory asthma managed with azathioprine

Introduction: Azathioprine is an immune-modulating agent used in the management of autoimmune diseases and in preventing graft rejection. Its role in the management of refractory asthma is not very well-established.Case study: A 47-year-old female with an underlying severe refractory asthma, managed with high dose steroids, was seen as an outpatient. Her course was complicated by frequent asthma exacerbation and severe adverse effects of chronic steroid use. Her symptoms did not respond to standard asthma management per Guidelines for the Diagnosis and Management of Asthma 1. She was tried on other management which included methotrexate and omalizumab injections without success. Azathioprine was started as a steroid-sparing agent following which her symptoms showed dramatic improvement with fewer exacerbations, higher peak flow measurements, and she was able to wean down her daily prednisone dose from 60 mg/day to 5 mg/day.Conclusion: Azathioprine is still an investigational agent for the management of asthma and more research needs to be done to evaluate its role. To our knowledge, this is the second case report which details the therapeutic role of Azathioprine in the management of asthma.

The NR3C1 Glucocorticoid Receptor Gene Polymorphisms May Modulate the TGF-beta mRNA Expression in Asthma Patients

Glucocorticosteroids (GCs) are basic drugs in therapy of a number of diseases, including chronic diseases of the respiratory system. They are the most important anti-inflammatory drugs in the treatment of asthma. GCs after binding to the glucocorticoid receptor (GR) form the complex (transcription factor), which acts on promoter and regulatory parts of genes enhancing the expression of anti-inflammatory proteins and decreasing the proinflammatory protein synthesis, including numerous cytokines mediating inflammation in the course of asthma. Non-sensitivity or resistance to GCs favours an increase in the TGF-β expression. This cytokine plays a central role in asthma inducing fibroblast differentiation and extracellular matrix synthesis. TGF-β isoforms, 1, 2 and 3, are located on chromosome 19q13, 1q41 and 14q24, respectively. GCs reduce TGF-β 1 and TGF-β 2 production and significantly decrease the expression of upregulated TGF-β 1 and TGF-β 2 mRNA induced by exogenous TGF-β. In asthma, TGF-β may play a role in the development of the peribronchiolar and subepithelial fibrosis, which contributes to a significant clinical exacerbation of asthma. Therefore, it is possible that NR3C1 glucocorticoid receptor gene polymorphisms could exert varied effects on the TGF-β mRNA expression and fibrotic process in lungs of asthmatic patients. The aim of the study was to evaluate the impact of polymorphic forms (Tth111I, BclI, ER22/23EK, N363S) of the NR3C1 gene on the level of the TGF-β 1 mRNA expression. A total of 173 patients with asthma and 163 healthy volunteers participated in the study. Genotyping of Tth111I, BclI, ER22/23EK, and N363S polymorphisms of the NR3C1 gene was performed by using PCR-HRM and PCR-RFLP techniques. TGF-β mRNA was assessed by real time RT-PCR. Tth111I SNP significantly (p = 0.0115) correlated with the TGF-β 1 mRNA expression level. The significance of AA and GG genotypes of Tth111I SNP in increasing and decreasing the level of the TGF-β 1 mRNA expression was demonstrated. Both BclI SNP and ER22/23EK SNP did not affect the expression level of the cytokine analysed. The N363S SNP AA genotype of NR3C1 gene statistically significantly influenced the increase in the level of the TGF-β 1 mRNA expression. Thus, SNPs of NR3C1 gene play an important regulatory function in the bronchi of patients suffering from asthma. In the case of the occurrence of Tth111I and N363S polymorphic forms of the gene studied, a reduced ability of GCs to inhibit the TGF-β 1 expression can be observed.

Severe asthma in adults: an orphan disease?

Severe asthma affects fewer than 10% of patients with asthma, is associated with a severe risk of death and disability, has a great impact on health and quality of life, and represents a huge cost to patients and society. Given the poor response to treatment and the side effects associated with medications for severe asthma, more efficient, cost-effective, and phenotype-specific medications are needed. Considering severe asthma as an orphan disease could encourage the pharmaceutical industry to stratify studies based on a more detailed characterization of study subjects at baseline, resulting in the development of novel therapeutic approaches.

Innate and adaptive immune responses in asthma

The recognition that asthma is primarily an inflammatory disorder of the airways associated with T helper type 2 (T(H)2) cell-dependent promotion of IgE production and recruitment of mast cells and eosinophils has provided the rationale for disease control using inhaled corticosteroids and other anti-inflammatory drugs. As more has been discovered about the cytokine, chemokine and inflammatory pathways that are associated with T(H)2-driven adaptive immunity, attempts have been made to selectively inhibit these in the hope of discovering new therapeutics as predicted from animal models of allergic inflammation. The limited success of this approach, together with the recognition that asthma is more than allergic inflammation, has drawn attention to the innate immune response in this disease. Recent advances in our understanding of the sentinel role played by innate immunity provides new targets for disease prevention and treatment. These include pathways of innate stimulation by environmental or endogenous pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs) to influence the activation and trafficking of DCs, innate sources of cytokines, and the identification of new T cell subsets and lymphoid cells.

Pathophysiology of asthma: what has our current understanding taught us about new therapeutic approaches?

Current asthma therapy is based on the use of adrenergic bronchodilator and anti-inflammatory drugs the specificity, efficacy, duration of action, and safety of which have been derived through classical pharmacology and medicinal chemistry. That asthma is a T(H)2-type inflammatory disorder frequently associated with atopy and allergic comorbidities has led to a concentrated effort to find treatments that act selectively on this pathway. A systematic literature review was undertaken, as well as a review of the Web site Clinicaltrials.gov for ongoing trials. Targets have included T cells themselves and their associated cytokines, chemokines, and receptors mostly targeted with biological agents. With the exception of anti-human IgE, none of these have met the expectations predicted from animal models and human in vitro tests. For most of these new therapies, only a very small subpopulation appears to respond. A case is made for a different approach to drug discovery based on acquiring a greater understanding of asthma stratification, the relevant pathways involved, and the development of appropriate diagnostic tests enabling the targeting of selective treatments to those asthmatic phenotypes most likely to respond. The recognition that asthma is more than allergy mandates improved predictive animal models and an appreciation that many of the environmental insults that initiate, consolidate, and exacerbate asthma operate through an epithelium functioning in a disorderly fashion. An integrated model that places the epithelium at the forefront of asthma pathogenesis suggests that greater emphasis should be placed on therapeutics that increase the airways' resistance against the inhaled environment rather than focusing only on suppression of inflammation.

Asthma management and prevention: current perspectives

The continuing evolution of asthma treatment and prevention are reflected in updated guidelines from the National Asthma Education and Prevention Program and Global Initiative for Asthma as well as other recent publications. The 2007 Expert Panel Report 3 guidelines designate severity and control, mediated by considerations of current impairment and future risk, as the primary concepts in assessing and monitoring asthma. Severity should ideally be determined at the time of diagnosis, after which control becomes the central focus of asthma management. In the area of treatment, inhaled corticosteroids (ICSs) remain first-line therapy for long-term asthma management in children and adults. For patients whose severity of asthma requires more than low-dose ICSs, or whose asthma cannot be well controlled on monotherapy with low-dose ICSs, evidence supports the efficacy of combination therapy consisting of an ICS plus an inhaled long-acting beta(2)-agonist (LABA) or an increase to medium-dose ICSs. For children >5 years of age and adults not controlled on low-dose ICSs, the combination of a low-dose ICS plus an inhaled LABA is equivalent in terms of outcomes to the use of medium-dose ICS. For children <5 years of age not controlled on low-dose ICSs, increasing the dose of ICSs is preferred to the addition of a LABA to low-dose ICS therapy as no studies using combination therapy have been conducted for patients in this age group. With regard to asthma prevention, approaches to primary prevention (to avoid allergen sensitization) and secondary prevention (to avoid disease progression) are still very much in the developmental stage, while tertiary prevention (to avoid asthmatic stimuli) has been more successful particularly in pediatric patients. Written action plans as part of self-management processes appear to improve physician-patient communication and disease status tracking. Other considerations in successful asthma management include patient education and monitoring of adherence to treatment regimens.

Asthma management and prevention: current perspectives

The continuing evolution of asthma treatment and prevention are reflected in updated guidelines from the National Asthma Education and Prevention Program and Global Initiative for Asthma as well as other recent publications. The 2007 Expert Panel Report 3 guidelines designate severity and control, mediated by considerations of current impairment and future risk, as the primary concepts in assessing and monitoring asthma. Severity should ideally be determined at the time of diagnosis, after which control becomes the central focus of asthma management. In the area of treatment, inhaled corticosteroids (ICSs) remain first-line therapy for longterm asthma management in children and adults. For patients whose severity of asthma requires more than low-dose ICSs, or whose asthma cannot be well controlled on monotherapy with low-dose ICSs, evidence supports the efficacy of combination therapy consisting of an ICS plus an inhaled long-acting beta2-agonist (LABA) or an increase to medium-dose ICSs. For children >5 years of age and adults not controlled on low-dose ICSs, the combination of a low-dose ICS plus an inhaled LABA is equivalent in terms of outcomes to the use of medium-dose ICS. For children <5 years of age not controlled on low-dose ICSs, increasing the dose of ICSs is preferred to the addition of a LABA to low-dose ICS therapy as no studies using combination therapy have been conducted for patients in this age group. With regard to asthma prevention, approaches to primary prevention (to avoid allergen sensitization) and secondary prevention (to avoid disease progression) are still very much in the developmental stage, while tertiary prevention (to avoid asthmatic stimuli) has been more successful particularly in pediatric patients. Written action plans as part of self-management processes appear to improve physician-patient communication and disease status tracking. Other considerations in successful asthma management include patient education and monitoring of adherence to treatment regimens.

Steroid resistance in asthma: mechanisms and treatment options

Glucocorticoid insensitivity presents a profound management problem in patients with asthma because conventional therapies are not effective. Glucocorticoids, acting through the glucocorticoid receptor (GR), are able to selectively repress inflammatory gene expression by utilizing several distinct mechanisms targeting nuclear factor-varphiB and activator protein-1 activation complexes and by effects on mitogen-activated protein kinases. Different model systems often activate distinct sets of signaling molecules and different glucocorticoid responsiveness may result from differences in concentrations and timing of steroid treatment of cells, GR expression levels, and the precise inflammatory stimulus used. Thus, abnormal activation of many signaling pathways may affect corticosteroid responsiveness in patients with corticosteroid-resistant asthma. Understanding the molecular mechanisms of GR action and inaction may lead to the development of new anti-inflammatory drugs or enable clinicians to reverse the relative steroid-insensitivity that is characteristic of some patients with severe asthma.