Th2/Th17 reciprocal regulation: twists and turns in the complexity of asthma phenotypes

Evolution of pathologic B-cell subsets and serum environment-specific sIgEs in patients with atopic dermatitis and controls, from infancy to adulthood

BACKGROUND

While B-cells have historically been implicated in allergy development, a growing body of evidence supports their role in atopic dermatitis (AD). B-cell differentiation across ages in AD, and its relation to disease severity scores, has not been well defined.

OBJECTIVE

To compare the frequency of B-cell subsets in blood of 0-5, 6-11, 12-17, and ≥18 years old patients with AD versus age-matched controls.

METHODS

Flow cytometry was used to measure B-cell subset frequencies in the blood of 27 infants, 17 children, 11 adolescents, and 31 adults with moderate-to-severe AD and age-matched controls. IgD/CD27 and CD24/CD38 core gating systems and an 11-color flow cytometry panel were used to determine frequencies of circulating B-cell subsets. Serum total and allergen-specific IgE (sIgEs) levels were measured using ImmunoCAP®.

RESULTS

Adolescents with AD had lower frequencies of major B-cells subsets (p < .03). CD23 expression increased with age and was higher in AD compared to controls across all age groups (p < .04). In AD patients, multiple positive correlations were observed between IL-17-producing T-cells and B-cell subsets, most significantly non-switched memory (NSM) B-cells (r = .41, p = .0005). AD severity positively correlated with a list of B-cell subsets (p < .05). IL-9 levels gradually increased during childhood, reaching a peak in adolescence, paralleling allergen sensitization, particularly in severe AD. Principal component analysis of the aggregated environmental sIgE data showed that while controls across all ages tightly clustered together, adolescents with AD demonstrated distinct clustering patterns relative to controls.

CONCLUSIONS

Multiple correlations between B-cells and T-cells, as well as disease severity measures, suggest a complex interplay of immune pathways in AD. Unique B-cell signature during adolescence, with concurrent allergen sensitization and IL-9 surge, point to a potentially wider window of opportunity to implement interventions that may prevent the progression of the atopic march.

Transcriptomic Analysis of the Major Orphan Ichthyosis Subtypes Reveals Shared Immune and Barrier Signatures

Preliminary work suggested upregulation of inflammatory pathways in patients with common forms of ichthyosis. However, a comprehensive characterization of skin from various ichthyosis subtypes is unavailable, precluding the development of targeted treatments. Thus, we sought to characterize the immune and barrier profiles of common and subtype-specific skin transcriptomes in a large group of patients with ichthyosis. We performed a global RNA-sequencing analysis in 54 patients with ichthyosis (7 with Netherton syndrome, 13 with epidermolytic ichthyosis, 16 with lamellar ichthyosis, and 18 with congenital ichthyosiform erythroderma) and 40 healthy controls. Differentially expressed genes were defined on the basis of fold changes > 2 and false discovery rate < 0.05 criteria. We found robust and significant T helper (Th) 22/Th17 skewing in all subtypes (e.g., IL-17A/C/F, S100A7/8/9/12; P < 0.001) with modest changes in Th2 pathway, primarily in Netherton syndrome, and Th1 skewing in congenital ichthyosiform erythroderma. Across all subtypes (less evident in epidermolytic ichthyosis), lipid metabolism and barrier junction markers were downregulated (e.g., FA2H, CDH10/11/12/2; P < 0.05), whereas epidermal cornification and proliferation measures were upregulated (e.g., SPRR1A/1B/2C/2G, EREG; P < 0.05). Our findings suggest that the common ichthyosis variants share aberrations in Th17/Th22 and barrier function, with minimal Th2 modulation. This may help to elucidate the pathogeneses of these subtypes and inform the development of subtype-specific treatments.

What's the deal with efferocytosis and asthma?

Mucosal sites, such as the lung, serve as crucial, yet vulnerable barriers to environmental insults such as pathogens, allergens, and toxins. Often, these exposures induce massive infiltration and death of short-lived immune cells in the lung, and efficient clearance of these cells is important for preventing hyperinflammation and resolving immunopathology. Herein, we review recent advances in our understanding of efferocytosis, a process whereby phagocytes clear dead cells in a noninflammatory manner. We further discuss how efferocytosis impacts the onset and severity of asthma in humans and mammalian animal models of disease. Finally, we explore how recently identified genetic perturbations or biological pathway modulations affect pathogenesis and shed light on novel therapies aimed at treating or preventing asthma.

Cutaneous Manifestations in Biological-Treated Inflammatory Bowel Disease Patients: A Narrative Review

The biologic era has greatly improved the treatment of Crohn’s disease and ulcerative colitis. Biologics can however induce a wide variety of skin eruptions, especially those targeting the TNF-α and Th17 pathway. These include infusion reactions, eczema, psoriasis, lupus, alopecia areata, vitiligo, lichenoid reactions, granulomatous disorders, vasculitis, skin cancer, and cutaneous infections. It is important to recognize these conditions as treatment-induced adverse reactions and adapt the treatment strategy accordingly. Some conditions can be treated topically while others require cessation or switch of the biological therapy. TNF-α antagonists have the highest rate adverse skin eruptions followed by ustekinumab and anti-integrin receptor blockers. In this review, we provide an overview of the most common skin eruptions which can be encountered in clinical practice when treating IBD (Inflammatory bowel disease) patients and propose a therapeutic approach for each condition.

Therapeutic and prophylactic deletion of IL-4Ra-signaling ameliorates established ovalbumin induced allergic asthma

Background

Allergic asthma is a chronic inflammatory airway disease driven predominantly by a T_H2 immune response to environmental allergens. IL‐4Rα‐signaling is essential for driving T_H2‐type immunity to allergens. Anti‐T_H2 therapies have the potential to effectively reduce airway obstruction and inflammation in allergic asthma.

Objective

We investigated potential therapeutic effects of selective inhibition of this pathway in mice with established allergic airway disease. We further investigated whether IL‐4Rα disruption in systemically sensitized mice can prevent the onset of the disease.

Methods

We used Rosa^creERT2IL‐4Rα^−/lox mice, a tamoxifen (TAM)‐inducible IL‐4Rα knockdown model to investigate the role of IL‐4/IL‐13 signaling prior to the onset of the disease and during the effector phase in the ovalbumin‐induced allergic airway disease.

Results

Inducible deletion of IL‐4Rα demonstrated therapeutic effects, on established allergic airway disease, and prevented the development of ovalbumin‐induced airway hyperreactivity, eosinophilia, and goblet cell metaplasia in allergen‐sensitized mice. Interestingly, IL‐4Rα knockdown after allergic sensitization did not induce T_H17, a neutrophilic inflammatory response as observed in global IL‐4Rα‐deficient mice after intranasal allergen challenge.

Conclusion

Abrogation of IL‐4Rα signaling after allergic sensitization would have significant therapeutic benefit for T_H2‐type allergic asthma.

The role of interleukin-17 in asthma: a protective response?

While there now exist effective treatments for type 2 high, eosinophilic asthma, there are no specific therapies for 40–50% of people with asthma with other phenotypes, which result from poorly understood underlying pathological mechanisms. One such pathology is neutrophilic inflammation, which has been associated with interleukin (IL)-17 family cytokines. Human genetic studies identified IL-17 polymorphisms associated with asthma; in murine models of allergic airways disease, IL-17A contributes to airway hyperresponsiveness, and in humans, elevated airway IL-17A levels are repeatedly observed in severe asthma. However, the directionality of this association is unknown, and the assumption that IL-17 cytokines drive disease pathology remains speculative. Here, we explore the evidence underlying the relationship between IL-17 and asthma, we review lessons learned from investigating IL-17 in other inflammatory diseases, and discuss the possibility that IL-17 may even be protective in asthma rather than pathogenic. We also critically examine the newly proposed paradigm of a reciprocal relationship between type 2 and type 17 airways inflammation. In summary, we suggest an association between IL-17 and asthma, but research is needed examining the diverse functions of these cytokines, their longitudinal stability, their response to clinical interventions, and for mechanistic studies determining whether they are protective or pathogenic.

IL-17 cytokines have been implicated in neutrophilic asthma by genetic, murine and human data. Here, previous studies are critiqued and the assumption their dominant role is pathogenic rather than protective of airway epithelial barrier integrity is challenged.http://bit.ly/3axB4Zs

Mechanisms and therapeutic strategies for non-T2 asthma

Non-T2 asthma is traditionally defined as asthma without features of T2 asthma. The definition is arbitrary and is generally based on the presence of neutrophils in sputum, or the absence (or normal levels) of eosinophils or other T2 markers in sputum (paucigranulocytic), airway biopsies or in blood. This definition may be imprecise as we gain more knowledge from applying transcriptomics and proteomics to blood and airway samples. The prevalence of non-T2 asthma is also difficult to estimate as most studies are cross-sectional and influenced by concomitant treatment with glucocorticosteroids, and by the presence of recognized or unrecognized airway infections. No specific therapies have shown any clinical benefits in patients with asthma that is associated with a non-T2 inflammatory process. It remains to be seen if such an endotype truly exists and to identify treatments to target that endotype. Meanwhile, identifying intense airway neutrophilia as an indicator of airway infection and airway hyperresponsiveness as an indicator of smooth muscle dysfunction, and treating them appropriately, and not increasing glucocorticosteroids in patients who do not have obvious T2 inflammation, seem reasonable.

Evolution of pathologic T-cell subsets in patients with atopic dermatitis from infancy to adulthood

BACKGROUND

The circulating immune phenotype was defined in adults and young children with early atopic dermatitis (AD), but chronologic changes in the blood of infants and children with AD through adolescence have not been explored.

OBJECTIVE

We sought to compare immune activation and cytokine polarization in the blood of 0- to 5-year-old (n = 39), 6- to 11-year-old (n = 26), 12- to 17-year-old (n = 21) and 18-year-old or older (n = 43) patients with AD versus age-matched control subjects.

METHODS

Flow cytometry was used to measure IFN-γ, IL-9, IL-13, IL-17, and IL-22 cytokine levels in CD4⁺/CD8⁺ T cells, with inducible costimulator molecule and HLA-DR defining midterm and long-term T-cell activation, respectively, within skin-homing/cutaneous lymphocyte antigen (CLA)⁺ versus systemic/CLA^- T cells. Unsupervised clustering differentiated patients based on their blood biomarker frequencies.

RESULTS

Although CLA⁺ T_H1 frequencies were significantly lower in infants with AD versus all older patients (P < .01), frequencies of CLA⁺ T_H2 T cells were similarly expanded across all AD age groups compared with control subjects (P < .05). After infancy, CLA^- T_H2 frequencies were increased in patients with AD in all age groups, suggesting systemic immune activation with disease chronicity. IL-22 frequencies serially increased from normal levels in infants to highly significant levels in adolescents and adults compared with levels in respective control subjects (P < .01). Unsupervised clustering aligned the AD profiles along an age-related spectrum from infancy to adulthood (eg, inducible costimulator molecule and IL-22).

CONCLUSIONS

The adult AD phenotype is achieved only in adulthood. Unique cytokine signatures characterizing individual pediatric endotypes might require age-specific therapies. Future longitudinal studies, comparing the profile of patients with cleared versus persistent pediatric AD, might define age-specific changes that predict AD clearance.

Increased cardiovascular and atherosclerosis markers in blood of older patients with atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is associated with increased systemic inflammation and cardiovascular risk. Although previous studies have found increased inflammatory proteins in the blood of patients with AD, detailed comparison among patients with AD of different ages is unavailable.

OBJECTIVE

To characterize the blood proteomic signature of patients with AD as a function of age.

METHODS

We used the OLINK high-throughput proteomic assay to measure serum inflammatory and cardiovascular risk proteins in 71 patients with moderate to severe AD from 3 age groups (18-40 years old [n = 26], 41-60 years old [n = 24], and >60 years old [n = 21]) compared with 37 age-matched controls. Total and allergen-specific serum IgEs were also measured.

RESULTS

When we compared patients with AD from 3 different age groups with their respective controls, we identified a total of 172 differentially expressed proteins. T_H2 chemokines (CCL13, CCL17) were consistently elevated in patients with AD across all ages (P < .05), whereas T_H1 (CXCL10) and T_H17 (KYNU, CCL20) markers incrementally increased with age in both patients with AD and healthy subjects. Elderly patients with AD (>60 years old) exhibited striking upregulation of key proinflammatory proteins, including markers of atherosclerosis (CCL4, CCL7, SORT1), cardiovascular risk (GDF15, MPO, ST2), cell adhesion (CDH3), and apoptosis (FAS; all P < .05) compared with younger patients with AD and age-matched controls. We also found that total and allergen-specific serum IgEs decreased significantly with age in patients with AD (P < .05).

CONCLUSION

Elderly patients with AD had increased levels of systemic inflammatory markers, including those associated with cardiovascular and atherosclerosis risk, which may explain their increased incidence of cardiovascular disease. This finding suggests that older patients with AD may benefit from cardiovascular disease screening and prevention.

Antagonistic effect of vitamin E on nAl2O3-induced exacerbation of Th2 and Th17-mediated allergic asthma via oxidative stress

Some basic research has shown that nanomaterials can aggravate allergic asthma. However, its potential mechanism is insufficient. Based on the research that alumina nanopowder (nAl₂O₃) has been reported to cause lung tissue damage, the purpose of this study was to explore the relationship between nAl₂O₃ and allergic asthma as well as its molecular mechanism. In this study, Balb/c mice were sensitized with ovalbumin (OVA) to construct the allergic asthma model while intratracheally administered 0.5, 5 or 50 mg kg^-1·day^-1 nAl₂O₃ for 3 weeks. It was observed that exposure to nAl₂O₃ exacerbated airway hyperresponsiveness (AHR), airway remodeling, and inflammation cell infiltration, leading to lung function damage in mice. Results revealed that nAl₂O₃ could increase ROS levels and decrease GSH levels in lung tissue, promote the increases of the T-IgE, TGF-β, IL-1β and IL-6 levels, stimulate the overexpression of transcription factors GATA-3 and RORγt, decrease the levels of IFN-γ and IL-10 and increase the levels of IL-4 and IL-17A, resulting in the imbalance of Th1/Th2 and Treg/Th17 immune responses. In addition, antioxidant Vitamin E (Vit E) could alleviate asthma-like symptoms through blocking oxidative stress. The study displayed that exposure of nAl₂O₃ deteriorated allergic asthma through promoting the imbalances of Th1/Th2 and Treg/Th17.

Th17 cells in Bulgarian children with chronic obstructive lung diseases

INTRODUCTION AND OBJECTIVES

Th17 lymphocytes are now widely believed to be critical in various chronic pulmonary diseases. However, there is still a small number of investigations regarding children. We aimed to assess the percentage of Th17 lymphocytes and IL-17A in peripheral blood of children with chronic obstructive lung diseases.

PATIENTS AND METHODS

We included a total of 42 children: 20 with bronchial asthma (BA), 12 with cystic fibrosis (CF) and 10 healthy children without a history of allergies, aged 4-17 years. Th17 cells (CD3+CD4+CD161+CCR6+) were determined in peripheral blood by flow cytometry. The concentration of serum IL-17A was measured by ELISA.

RESULTS

The BA patients had a significantly higher percentage of Th17 (12.40±1.16%) compared to the CF children (7.64±0.87%, p=0.0035) and healthy (7.25±0.45%, p=0.008). Stratifying the BA group, we found higher levels of Th17 in patients with severe BA (p=0.03), whereas patients with moderate BA had Th17 cells close to those in CF and healthy children. We found that patients with better control of BA had Th17 closer to those with CF (p=0.98) than BA children with poor control (p<0.001) (post hoc, Bonferroni correction). CF patients with concomitant P. aeruginosa infection showed slightly higher percentages of Th17 cells than those without infection (8.08±3.09% vs. 6.25±2.42%, p=0.294).

CONCLUSIONS

The percentage of Th17 cells was significantly increased in the peripheral blood of children with severe BA compared to the children with moderate BA, which suggests that the former could possibly benefit from future target therapies.

Atopic dermatitis in African American patients is TH2/TH22-skewed with TH1/TH17 attenuation

BACKGROUND

African Americans (AA) are disproportionately impacted by atopic dermatitis (AD), with increased prevalence and therapeutic challenges unique to this population. Molecular profiling data informing development of targeted therapeutics for AD are derived primarily from European American (EA) patients. These studies are absent in AA, hindering development of effective treatments for this population.

OBJECTIVE

We sought to characterize the global molecular profile of AD in the skin of AA patients as compared with that of EA AD and healthy controls.

METHODS

We performed RNA-Seq with reverse transcription polymerase chain reaction validation and immunohistochemistry studies in lesional and nonlesional skin of AA and EA AD patients vs healthy controls.

RESULTS

African American AD lesions were characterized by greater infiltration of dendritic cells (DCs) marked by the high-affinity immunoglobulin E (IgE) receptor (FcεR1+) compared with EA AD (P < .05). Both AD cohorts showed similarly robust up-regulation of Th2-related (CCL17/18/26) and Th22-related markers (interleukin [IL]-22, S100A8/9/12), but AA AD featured decreased expression of innate immune (tumor necrosis factor [TNF], IL-1β), Th1-related (interferon gamma [IFN-γ], MX1, IL-12RB1), and Th17-related markers (IL-23p19, IL-36G, CXCL1) vs EA AD (P < .05). The Th2 (IL-13) and Th22-related products (IL-22, S100A8/9/12) and serum IgE were significantly correlated with clinical severity (Scoring of Atopic Dermatitis [SCORAD]) in AA. Fillagrin (FLG) was exclusively down-regulated in EA AD, whereas loricrin (LOR) was down-regulated in both AD cohorts and negatively correlated with SCORAD in AA.

CONCLUSION

The molecular phenotype of AA AD skin is characterized by attenuated Th1 and Th17 but similar Th2/Th22-skewing to EA AD. Our data encourages a personalized medicine approach accounting for phenotype-specific characteristics in future development of targeted therapeutics and clinical trial design for AD.

Intranasal instillation of miR‑410 targeting IL‑4/IL‑13 attenuates airway inflammation in OVA‑induced asthmatic mice

Asthma is a common chronic inflammatory respiratory disease characterised by airway inflammation and hyperresponsiveness. The present study was designed to clarify the effect of intranasal miR-410 administration in an ovalbumin (OVA)-induced murine model of asthma. It was found that miR-410 expression was significantly decreased in the lungs of OVA-induced asthmatic mice (P<0.05) and miR-410 was overexpressed via intranasal instillation. Bioinformatics indicated that the 3′-untranslated regions of interleukin (IL)-4 and IL-13 messenger RNAs (mRNAs) contain miR-410 binding sites. The IL-4 and IL-13 genes were confirmed to be miR-410-regulated using the dual-luciferase reporter assay. Additionally, intranasal administration of miR-410 markedly attenuated airway inflammation and reduced infiltration of inflammatory cells into bronchoalveolar lavage fluid (P<0.05) as determined by bronchoalveolar lavage fluid analysis. Moreover, miR-410 significantly decreased the lung expression of IL-4 and IL-13 (P<0.05), although the levels of mRNAs encoding IL-4 and IL-13 in lungs did not change significantly as determined by real-time PCR analysis. In conclusion, we found that intranasal administration of miR-410 effectively inhibited airway inflammation in OVA-induced asthmatic mice by targeting IL-4 and IL-13 at the post-transcriptional level. miR-410 is thus a promising treatment for allergic asthma.

The Cell Research Trends of Asthma: A Stem Frequency Analysis of the Literature

Objective

This study summarized asthma literature indexed in the Medical Literature Analysis and Retrieval System Online (MEDLINE) and explored the history and present trends of asthma cell research by stem frequency ranking to forecast the prospect of future work.

Methods

Literature was obtained from MEDLINE for the past 30 years and divided into three groups by decade as the retrieval time. The frequency of stemmed words in each group was calculated using Python with Apache Spark and the Natural Language Tool Kit for ranking. The unique stems or shared stems of 3 decades were summarized.

Results

A total of 1331, 4393, and 7215 records were retrieved from 3 decades chronologically, and the stem ranking of the top 50 were listed by frequency. The number of stems shared with 3 decades was 26 and with the first and last 2 decades was 5 and 13.

Conclusions

The number of cell research studies of asthma has increased rapidly, and scholars have paid more attentions on experimental research, especially on mechanistic research. Eosinophils, mast cells, and T cells are the hot spots of immunocyte research, while epithelia and smooth muscle cells are the hot spots of structural cell research. The research trend is closely linked with the development of experimental technology, including animal models. Early studies featured basic research, but immunity research has dominated in recent decades. The distinct definition of asthma phenotypes associated with genetic characteristics, immunity research, and the introduction of new cells will be the hot spots in future work.

Intraperitoneal administration of the anti-IL-23 antibody prevents the establishment of intestinal nematodes in mice

Previous studies have established that an increased Th-9 response creates a hostile environment for nematode parasites. Given that IL-23, a cytokine required for maintenance of the IL-17-secreting phenotype, has inhibitory effects on IL-9 production, we hypothesized that reducing circulating IL-23 by treatment with anti-IL-23 antibodies would reduce the establishment and development of parasitic intestinal nematodes. In this study, we show that animals treated with anti-IL-23 monoclonal antibodies showed a drastic reduction in the number of mouse pinworms (Aspiculuris tetraptera) recovered from the intestine (p < 0.001) at 23 days post-infection compared to the untreated animals. The cytokine levels in Peyer's patches (PP) in treated and infected animals increase the expression of interleukins such as IL-25, IL-21, and IL-9, augmenting mucus production in the crypts, and boosting chemokines, such as OX40 and CCL20 in the mucosa. Our results suggest that the Th17/Th2 regulatory mechanism provoked by the administration of the anti-IL-23 antibody prevents the implantation of the intestinal nematode in mice. The diminished inflammatory IL-17 levels alter the Th9 environment perhaps as a consequence of IL-17 inhibiting IL-9 expression. These Th9 conditions may explain the successful treatment against Inflammatory Bowel Disease (IBD) both with antibodies against IL-23 or through parasitization with nematodes.

The Influence of the Microbiome on Early-Life Severe Viral Lower Respiratory Infections and Asthma-Food for Thought?

Severe viral lower respiratory infections are a major cause of infant morbidity. In developing countries, respiratory syncytial virus (RSV)-bronchiolitis induces significant mortality, whereas in developed nations the disease represents a major risk factor for subsequent asthma. Susceptibility to severe RSV-bronchiolitis is governed by gene-environmental interactions that affect the host response to RSV infection. Emerging evidence suggests that the excessive inflammatory response and ensuing immunopathology, typically as a consequence of insufficient immunoregulation, leads to long-term changes in immune cells and structural cells that render the host susceptible to subsequent environmental incursions. Thus, the initial host response to RSV may represent a tipping point in the balance between long-term respiratory health or chronic disease (e.g., asthma). The composition and diversity of the microbiota, which in humans stabilizes in the first year of life, critically affects the development and function of the immune system. Hence, perturbations to the maternal and/or infant microbiota are likely to have a profound impact on the host response to RSV and susceptibility to childhood asthma. Here, we review recent insights describing the effects of the microbiota on immune system homeostasis and respiratory disease and discuss the environmental factors that promote microbial dysbiosis in infancy. Ultimately, this knowledge will be harnessed for the prevention and treatment of severe viral bronchiolitis as a strategy to prevent the onset and development of asthma.