The basic immunology of asthma.

In many asthmatics, chronic airway inflammation is driven by IL-4-, IL-5-, and IL-13-producing Th2 cells or ILC2s. Type 2 cytokines promote hallmark features of the disease such as eosinophilia, mucus hypersecretion, bronchial hyperresponsiveness (BHR), IgE production, and susceptibility to exacerbations. However, only half the asthmatics have this "type 2-high" signature, and "type 2-low" asthma is more associated with obesity, presence of neutrophils, and unresponsiveness to corticosteroids, the mainstay asthma therapy. Here, we review the underlying immunological basis of various asthma endotypes by discussing results obtained from animal studies as well as results generated in clinical studies targeting specific immune pathways.

Qingfei oral liquid alleviates airway hyperresponsiveness and mucus hypersecretion via TRPV1 signaling in RSV-infected asthmatic mice.

Pediatric asthma is exacerbated by Respiratory Syncytial Virus (RSV) infection, and Transient Receptor Potential Vanilloid 1 (TRPV1) promotes production of inflammatory cytokines and mucus hypersecretion in the pathology of this disease. Our previous research revealed that Qingfei oral liquid (QF) inhibited airway inflammation and mucus hypersecretion in RSV-infected asthmatic mice models and that this may be associated with the TRPV1-regulation of NF-κB and Mucin 5AC (MUC5AC) expression, but the exact mechanism is unknown. In the present study, LC-MS was used for analyzing the chemicals in QF, ovalbumin (OVA)-induced asthmatic mice inhaled RSV three consecutive times to create an RSV-infected asthmatic model. We found treatment from QF alleviated airway hyperresponsiveness (AHR) and reduced congestion, edema, and infiltration of inflammatory cells into pulmonary tissues. Additionally, QF was found to decrease expression of NF-κB and its downstream inflammatory cytokines IL-1ß, IL-4, IL-5, and IL-13, as well as a decrease in MUC5AC and pro-inflammatory cytokines in PKC via a reduction in Protein Kinase C-dependent signaling. These findings suggest that QF can alleviate AHR and mucus hypersecretion caused by RSV infection in asthmatic mice, and its mechanism may be associated with the regulation of the TRPV1 signaling pathway.

Pelargonium sidoides radix extract EPs 7630 reduces rhinovirus infection through modulation of viral binding proteins on human bronchial epithelial cells.

Bronchial epithelial cells are the first target cell for rhinovirus infection. The course of viral infections in patients with acute bronchitis, asthma and COPD can be improved by oral application of Pelargonium sidoides radix extract; however, the mechanism is not well understood. This study investigated the in vitro effect of Pelargonium sidoides radix extract (EPs 7630) on the expression of virus binding cell membrane and host defence supporting proteins on primary human bronchial epithelial cells (hBEC). Cells were isolated from patients with severe asthma (n = 6), moderate COPD (n = 6) and non-diseased controls (n = 6). Protein expression was determined by Western-blot and immunofluorescence. Rhinovirus infection was determined by immunofluorescence as well as by polymerase chain reaction. Cell survival was determined by manual cell count after live/death immunofluorescence staining. All parameters were determined over a period of 3 days. The results show that EPs 7630 concentration-dependently and significantly increased hBEC survival after rhinovirus infection. This effect was paralleled by decreased expression of the inducible co-stimulator (ICOS), its ligand ICOSL and cell surface calreticulin (C1qR). In contrast, EPs 7630 up-regulated the expression of the host defence supporting proteins ß-defensin-1 and SOCS-1, both in rhinovirus infected and un-infected hBEC. The expression of other virus interacting cell membrane proteins such as MyD88, TRL2/4 or ICAM-1 was not altered by EPs 7630. The results indicate that EPs 7630 may reduce rhinovirus infection of human primary BEC by down-regulating cell membrane docking proteins and up-regulating host defence proteins.

Impact of two oral doses of 100,000 IU of vitamin D3 in preschoolers with viral-induced asthma: a pilot randomised controlled trial.

BACKGROUND: New evidence supports the use of supplemental vitamin D in the prevention of exacerbation of asthma; however, the optimal posology to sufficiently raise serum levels while maximising adherence is unclear. The objective was to ascertain the efficacy of high-dose vitamin D3 in increasing serum vitamin D in preschoolers with asthma and provide preliminary data on safety and efficacy outcomes. METHODS: We conducted a 7-month, triple-blind, randomised, placebo-controlled, pilot trial of children aged 1-5 years with viral-induced asthma. Participants were allocated to receive two oral doses of 100,000 IU vitamin D3 (intervention) or identical placebo (control) 3.5 months apart, once in the fall and once in the winter. Serum 25-hydroxyvitamin D (25OHD) was measured by tandem mass spectrometry at baseline, 10 days, 3.5 months, 3.5 months + 10 days, and 7 months. The main outcome was the change in serum 25OHD from baseline (Δ25OHD) over time and at 3.5 and 7 months; other outcomes included the proportion of children with 25OHD ≥ 75 nmol/L, safety, and adverse event rates. RESULTS: Children (N = 47) were randomised (intervention, 23; control, 24) in the fall. There was a significant adjusted group difference in the Δ25OHD (95% confidence interval) of 57.8 (47.3, 68.4) nmol/L, p < 0.0001), with a time (p < 0.0001) and group*time interaction effect (p < 0.0001), in favour of the intervention. A significant group difference in the Δ25OHD was observed 10 days after the first (119.3 [105.8, 132.9] nmol/L) and second (100.1 [85.7, 114.6] nmol/L) bolus; it did not reach statistical significance at 3.5 and 7 months. At 3.5 and 7 months, respectively, 63% and 56% of the intervention group were vitamin D sufficient (≥ 75 nmol/L) compared to 39% and 36% of the control group. Hypercalciuria, all without hypercalcaemia, was observed in 8.7% of intervention and 10.3% of control samples at any time point. Exacerbations requiring rescue oral corticosteroids, which appear as a promising primary outcome, occurred at a rate of 0.87/child. CONCLUSION: Two oral boluses of 100,000 IU vitamin D3,once in the fall and once in the winter, rapidly, safely, and significantly raises overall serum vitamin D metabolites. However, it is sufficient to maintain 25OHD ≥ 75 nmol/L throughout 7 months in only slightly more than half of participants. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02197702 (23 072014). Registered on 23 July 2014.

Vitamin D intervention in preschoolers with viral-induced asthma (DIVA): a pilot randomised controlled trial.

BACKGROUND: Trials in school-aged children suggest vitamin D supplementation reduces asthma exacerbations. Primary aim: to examine whether vitamin D3 (100,000 IU) rapidly raises serum 25-hydroxyvitamin D (25OHD) ≥75 nmol/L in asthmatic preschoolers. METHODS: In a double-blind, randomised, placebo-controlled trial, preschool-aged children with asthma received 100,000 IU vitamin D3 (intervention) or placebo (control), followed by 400 IU vitamin D3 daily for 6 months. Serum 25OHD was measured at baseline, 10 days, 3 and 6 months. Outcomes included the group difference in 25OHD change from baseline at 3 months (Δ25OHD); the proportion of children with 25OHD ≥75 nmol/L at 3 months; the pattern in serum vitamin D over 6 months; the proportion of children with hypercalciuria at any time point (safety); and group rates for oral corticosteroids. Continuous outcomes were analysed using generalised linear mixed models and group rate ratios of events per child were assessed using a Poisson distribution model. RESULTS: Twenty-two children were randomised (intervention:11; control:11) during winter. At 3 months, the group difference in Δ25OHD (7.2 nmol/L; 95 % CI: -13.7, 28.1) was not significant; yet, 100 % versus 54.5 % (intervention versus control) had serum 25OHD ≥75 nmol/L. There was a significant group difference in Δ25OHD at 10 days (110.3 nmol/L; 95 % CI: 64.0, 156.6). One child in each group had transient hypercalciuria at 10 days. Group oral corticosteroids rates were 0.82 and 1.18/child, intervention versus control (rate ratio = 0.68; 95 % CI: 0.30, 1.62; non-significant). CONCLUSIONS: Following 100,000 IU vitamin D3, all children reached serum 25OHD ≥75 nmol/L, compared with half who received placebo. Daily supplementation, sun exposure and insufficient power may explain the absence of a significant 3-month group difference in Δ25OHD. No clinically important alterations in bone metabolism biomarkers occurred. Group oral corticosteroid rates will inform sample size calculations for the larger trial. ( NCT01999907 , 25 November 2013).

Do we really need to keep redesigning ß2-agonists for the management of asthma?

There is an enormous drive to refine therapeutic designs and delivery systems, but in this review we ask if this is always the right direction? We choose to play devil's advocate, and argue that refining drug design is not always needed, and what is actually needed is a greater understanding of the biology of the disease. Here we focus on asthma and the ß2-agonist group of bronchodilators as an example of how a class of therapeutic has been developed and continues to be developmentally refined. In this review, we define viral-induced exacerbations as the greatest cause of lung attacks and the most crucial time ß2-agonist therapy is needed. We explore the reasons why ß2-agonist therapy fails in patients with rhinovirus-induced exacerbations, and explain why further "engineered" ß2-agonist therapies are likely to continue to fail in this subset of asthmatic population. We justify our perspective by returning to the biology that underlies the cause of disease and highlight the need for "more research" into alternative therapies for this population of asthmatic patients.

BuShenYiQi Formula strengthens Th1 response and suppresses Th2-Th17 responses in RSV-induced asthma exacerbated mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The prevalence of allergic asthma has been increased rapidly in recent years. About 20% of all these sufferers have experienced asthma exacerbation. Although corticosteroids and ß-agonists therapy improves serious asthma symptoms, they can׳t completely cure these allergic diseases. BuShenYiQi Formula (BSYQF) has been widely used to treat bronchial asthma and its exacerbation for decades in Huashan Hospital of Fudan University, China. Nevertheless, the mechanisms of BSYQF' anti-asthmatic effects haven׳t been fully elucidated. In this study, we evaluated the involvement of Th1, Th2 and Th17 cells in the anti-asthmatic effects of BSYQF in Respiratory Syncytial Virus (RSV)-induced asthma exacerbated mice. MATERIALS AND METHODS: BALB/c mice were challenged with ovalbumin (OVA), followed by RSV infections for establishment of asthma exacerbated model. Airway hyperresponsiveness (AHR) was examined by direct airway resistance analysis. Bronchoalveolar lavage fluid (BALF) was assessed for inflammatory cell counts and secreted levels of cytokines. Lung tissues were detected for inflammatory cell infiltration and mucus hypersecretion. Subsequently, CD4(+)T cells and alveolar macrophages were sorted and purified from mice lungs in different groups. CD4(+)T cell subpopulations including the expression levels of important transcription factors in T lymphocyte polarization were examined. In asthma exacerbation group, the purified CD4(+)T cells and macrophages were co-cultured, and the changes of co-cultured cells with BSYQF treatment were further analyzed in vitro. RESULTS: BSYQF significantly attenuated airway hyperresponsiveness and inhibited inflammatory cell infiltration, especially for excessive infiltration of eosinophils and neutrophils. Histopathological analysis showed that BSYQF could suppress airway inflammation and RSV replication. The decreases of antigen-specific IgE, IL-4, IL-5, IL-6, IL-17a and increases of IFN-γ, IL-12 were observed in BALF, lung homogenate or serum after BSYQF treatment. We further confirmed that BSYQF could down-regulate Th2-Th17 cell proportions with lower expressions of GATA3, STAT6 and RORγT, and up-regulate Th1 cell proportion with higher expression of T-bet. And as a result of strengthened Th1-response, activated macrophages were also observed by remarkable enhancement of signature gene expressions and phagocytosis. CONCLUSIONS: BSYQF can significantly attenuate RSV-induced asthma exacerbation. These effects may be mediated at least partially by regulating the balance between Th1 and Th2-Th17 responses.

Specific IgE against Staphylococcus aureus enterotoxins: an independent risk factor for asthma.

BACKGROUND: The role of IgE in patients with severe asthma is not fully understood. OBJECTIVE: We sought to investigate whether IgE to Staphylococcus aureus enterotoxins might be relevant to disease severity in adult asthmatic patients. METHODS: Specific IgE antibody concentrations in serum against enterotoxins, grass pollen (GP), and house dust mite allergens and total IgE levels were measured in adult cohorts of 69 control subjects, 152 patients with nonsevere asthma, and 166 patients with severe asthma. Severe asthma was defined as inadequately controlled disease despite high-dose inhaled corticosteroids plus at least 2 other controller therapies, including oral steroids. RESULTS: Enterotoxin IgE positivity was significantly greater in patients with severe asthma (59.6%) than in healthy control subjects (13%, P< .001). Twenty-one percent of patients with severe asthma with enterotoxin IgE were considered nonatopic. Logistic regression analyses demonstrated significantly increased risks for enterotoxin IgE-positive subjects to have any asthma (OR, 7.25; 95% CI, 2.7-19.1) or severe asthma (OR, 11.09; 95% CI, 4.1-29.6) versus enterotoxin IgE-negative subjects. The presence of GP or house dust mite IgE antibodies was not associated with either significantly increased risk for asthma or severity. Oral steroid use and hospitalizations were significantly increased in patients with enterotoxin IgE and nonatopic asthma. GP IgE was associated with a higher FEV(1) percent predicted value, and enterotoxin IgE was associated with a lower FEV(1) percent predicted value. CONCLUSIONS: Staphylococcal enterotoxin IgE antibodies, but not IgE against inhalant allergens, are risk factors for asthma severity. We hypothesize that the presence of enterotoxin IgE in serum indicates the involvement of staphylococcal superantigens in the pathophysiology of patients with severe asthma.

[Effects of San'ao decoction and its analogous prescriptions on airway inflammation in mice with respiratory syncytial virus- and ovalbumin-induced asthma].

OBJECTIVE: To evaluate the effects of San'ao decoction (SAD) and its analogous prescriptions (APs), compounds of traditional Chinese herbal medicine for asthma, on airway inflammation in mice with respiratory syncytial virus (RSV)- and ovalbumin (OVA)-induced asthma. METHODS: A total of 110 mice were randomly divided into control group, untreated group, dexamethasone (DM) group, small-dose SAD (SAD-S) group, large-dose SAD (SAD-L) group, AP I-S group, AP I-L group, AP II-S group, AP II-L group, AP III-S group, and AP III-L group. The asthma model was reproduced by sensitization with multipoint intraperitoneal injection of OVA, followed by repeated inhalation of OVA combined with intranasal instillation of RSV. Cells in bronchoalveolar lavage fluid (BALF) were counted and classified. The supernatant of the BALF was used for detecting the contents of interleukin-4 (IL-4), interleukin-5 (IL-5) and interferon-gamma (IFN-gamma) by enzyme-linked immunosorbent assay. Pathological changes in lung tissue were observed by hematoxylin and eosin staining and the scores of pathological changes were also calculated to determine the degree of inflammation. RESULTS: Compared with the control group, the amounts of lymphocytes, eosinophils, neutrophils in BALF in the untreated group were increased significantly (P<0.01); the changes of lung histopathology in the untreated group were much more serious, and the content of IFN-gamma was sharply decreased, while the contents of IL-4 and IL-5 were significantly increased (P<0.05). The counts of eosinophils in BALF of the treated groups all decreased obviously (P<0.01) as compared with the untreated group. The count of the neutrophils in BALF of the AP II-L group was obviously lower than that in the untreated group (P<0.01). Most of Chinese herbal formulas and DM could increase the level of IFN-gamma, and decrease the level of IL-4. All concentrations of the APs and SAD could decrease the level of IL-5 as compared with the untreated group, especially of the AP II-L and AP I-L (P<0.05, P<0.01). CONCLUSION: SAD and its APs had some therapeutic effects on RSV-induced asthma in mice. Among the formulas, AP II has a better therapeutic efficacy in treatment of asthma by decreasing the amount of neutrophils.

[Clinical study on effect of jiexiao oral liquid in preventing and curing virus induced asthma in children].

OBJECTIVE: To observe the effect and the possible mechanism of Jiexiao Oral Liquid (JXOL) in preventing and curing virus induced asthma in children. METHODS: One hundred and sixty patients of acute upper respiratory tract infection (AURTI) with asthma history were randomly divided into 2 groups. JXOL was given to the treated group within 24 hrs after occurrence of AURTI symptoms, and virazole of 10-15 mg.kg-1.d-1 was given to the control group, the therapeutic course for both groups was 7 days. Changes of clinical symptoms, signs, therapeutic effect, pulmonary function and immuno-globulin in patients were observed. RESULTS: The total effective rate of the treated group was 83.8%, the clinical control rate was 48.8%, while those in the control group were 62.5% and 23.8% respectively, showing significant difference between them (P < 0.01). JXOL could obviously improve the indexes of forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF), reduce the level of IgE, as compared with those before treatment, the difference was significant (P < 0.01 or P < 0.05); it also showed significant difference as compared with those in the control group after treatment. The changes of IgA, IgG and IgM after treatment showed insignificant difference. CONCLUSION: JXOL was effective in preventing and curing virus induced asthma in children, it also shows pulmonary function improving and immune regulating effects.

Expression of intercellular adhesion molecule-1 (ICAM-1) in nasal epithelial cells of atopic subjects: a mechanism for increased rhinovirus infection?

Since clinical experimental studies indicate that upper respiratory tract viral infections may exacerbate acute asthma symptoms in atopic/asthmatic individuals, we have investigated the expression and modulation of ICAM-1 on human nasal epithelial cells (HNEC) from normal and atopic subjects. ICAM-1 is the attachment molecule for the majority of serotypes of human rhinovirus (HRV), including HRV-14, and is also critical for the migration and activation of immune effector cells. Basal ICAM-1 expression was significantly higher in HNEC obtained by brushings from atopic compared with non-atopic subjects (P = 0.031), and was also significantly increased on atopic HNEC harvested in season compared with out of season (P < 0.05). Atopic HNEC showed further up-regulation in ICAM-1 expression when cultured with clinically relevant allergen (P = 0.032). ICAM-1 levels on normal HNEC were also increased by infection with HRV-14 (P < 0.05). Basal expression of ICAM-1 on atopic nasal polyp epithelial cells (EC) was significantly higher than on both normal and atopic nasal HNEC. This elevated nasal polyp ICAM-1 level was not increased further by allergen, although HRV infection resulted in a small significant increase. Recovered viral titres from HRV-infected nasal polyp EC were 1.5-fold higher than from infected normal nasal HNEC. The data are consistent with the hypothesis that allergen, by enhancing expression of the HRV attachment target on host cells, facilitates viral infection in atopic subjects; simultaneously HRV-induced increases in ICAM-1 levels would favour migration and activation of immune effector cells to the airway, resulting in enhanced atopic inflammation.