Biological mechanisms underlying the clinical effects of allergen-specific immunotherapy in asthmatic children

Effectiveness of sublingual immunotherapy with house dust mite drops in asthmatic children at different ages

Background

Respiratory allergies in children, such as asthma and rhinitis, are becoming progressively common every year. Recent studies found that pediatric patients with asthma receiving regular medication and specific immunotherapy (SIT) had improved therapeutic outcomes in a wide age range. However, there are few studies that have examined the effectiveness of SIT treatment in children with allergic asthma at different ages in terms of the degree of asthma control, improvements in lung function, and changes in exhaled nitric oxide (FeNO).

Method

A total of 200 asthmatic pediatric patients who had been receiving regular treatment for at least a year were split into the observation and the control groups, which depended on whether sublingual immunotherapy was added based on conventional treatment medicines. The children who were divided by an age cut-off of 6 years old in these two groups were compared before and after therapy based on the exhaled levels of FeNO, pulmonary function, visual analog scale, medication scores, daytime and nighttime ratings of asthma symptom, and rhinitis symptom scores.

Results

Before treatment, there was no significant difference between the observation group and the control group in various indicators of the patients under 6 years old; and in the older children (6-16 years old) group, the scores of FVC, FEV1, and FEF25 in the observation group were significantly lower than those in the control group (P < 0.05). The FEF75, FEF50, FEF25, and MMEF75/MMEF25 indexes in the observation group were significantly higher than those in the control group after treatment (P < 0.05), but there was no statistical significance in other indexes (P > 0.05). The scores of ACT, FEF75, FEF50, MMEF72/MMEF25, and FeNO in the observation group were all higher than those in the control group after treatment (P < 0.05), and the differences in other indexes were not statistically significant (P > 0.05). Between the young-age group and the elder group, there was no significant difference in all indexes in the observation group before and after treatment (P > 0.05).

Conclusion

Children with asthma of all ages can considerably benefit from sublingual immunotherapy. Specifically, younger patients showed greater tendency on the improvement of small airway resistance, whereas school-age children with asthma significantly improved their small airway resistance as well as their asthma control and inflammation alleviation.

Special Issue on ‘Asthma and Allergic Inflammation’

Asthma is a chronic inflammatory airway disease, driven by either allergic or non-allergic stimuli, which usually manifests as wheezing, reversible airflow limitation, and bronchial hyperresponsiveness [...]

Effects of subcutaneous immunotherapy in allergic rhinitis children sensitive to dust mites

BACKGROUND

Subcutaneous immunotherapy (SCIT) is now the only treatment that can modify the natural course of allergic rhinitis (AR). However, not all children with AR benefit from SCIT.

OBJECTIVE

To evaluate the efficacy of SCIT in dust-mites-induced AR children and explore correlative factors predicting treatment response to SCIT.

METHODS

225 children aged 4-17 years old with AR were recruited from January 2016 to September 2019, and monitored at baseline, 4, 12, and 24 months after the start of SCIT treatment. The visual-analogue-score (VAS) was used to assess the clinical symptoms. Multivariate binary logistic regression analyses and receiver operating characteristic curves were used to explore correlative factors in predicting the efficacy of SCIT.

RESULTS

The significant declines in VAS started after 4 months of SCIT and continued to improve throughout the study compared with baseline. An increase in children's age (OR=0.688, 95%CI: 0.479-0.988) and those with allergic history (OR=0.097, 95%CI: 0.009-1.095) were negatively associated with the risk of poor efficacy. Polysensitized children were more likely to suffer poor efficacy (OR=15.511 95%CI: 1.319-182.355). The clinical response at month 4 (r=0.707) and month 12 (r=0.925) was related to that at month 24. The area under the curve (AUC) for improvement at month 4 and month 12 was 0.746 and 0.860, respectively.

CONCLUSION

Our study confirmed the clinical efficacy of SCIT in AR children. Children with younger age, negative allergic history, and multiple allergens may predict a worse efficacy. The onset of action and the clinical response to SCIT in the second year can be predicted as early as by month 4.

Benefit Effect of Sublingual Dust Mite Drops on the Control of Asthma in Children

AIM

To evaluate the effect of sublingual dust mite drops on inhaled corticosteroid replacement and its effect on asthma control level.

METHODS

Two hundred children with asthma who had received regular treatment for one year or more were divided into the observation group (71 cases) and control group (89 cases) according to whether sublingual dust mite drops were added on the basis of conventional treatment drugs. After treatment, C-ACT score, VAS score, drug score, lung function, exhaled nitric oxide level, and "ICS avoidance" were compared between the two groups.

RESULTS

Before treatment, FVC and PEF25 scores in the observation group were lower than those in the control group, and the difference was statistically significant. There was no significant difference in other indicators between the two groups. There was no statistical significance in each index between the single allergic group and the multiple allergic group. Both the observation group and the control group showed statistically significant differences in each index before and after treatment. C-ACT score, FVC, FEV1, PEF, PEF75, PEF50, PEF25, MMEF75/MMEF25 after treatment were all higher than before treatment in both groups; VAS score, drug score and FeNO after treatment were all lower than before treatment. Except PEF, the difference between the observation group and the control group before and after treatment was statistically significant. Among them, after treatment, the increased values of C-ACT, FVC, FEV1, PEF75, PEF50, PEF25, MMEF75/MMEF25 in the observation group were higher than those in the control group, while the decreased values of VAS score, drug score and FeNO were higher than those in the control group. The differences were statistically significant. After treatment, the increased value of FEV1 in the single allergic group was higher than that in the multiple allergic group, and the difference was statistically significant. There was no statistical significance in the changes in other indexes between the two groups before and after treatment. The ICS avoidance rate in the observation group was 57.4% (58/100), higher than that in the control group (17.0%, 17/100), and the difference was statistically significant (χ2=35.108, P < 0.01). The ICS avoidance rate was 55.6% (15/27) in the single allergic group and 58.1% (43/74) in the multiple allergic group, and there was no significant difference between the two groups (χ2=0.053, P=0.818).

CONCLUSION

Sublingual dust mite drops can significantly improve the asthma control levels in children with asthma and have the effect of inhaled corticosteroid replacement.

Prevalence of food allergen and aeroallergen sensitization among children in Sichuan province

Food allergen and aeroallergen sensitization are common allergic diseases worldwide, with widely varying estimates of prevalence in children. Our study investigated the characteristics of ingestion and inhalation allergy among children from Sichuan province in Southwest China, so as to get public awareness of these disorders.A total of 1722 children between 0 and 14 years' old were enrolled in this study. They were outpatients in the West China Second University Hospital during June 2019 to September 2019. Serum specific IgE specific to 10 types of food allergen and 10 types of aeroallergen were estimated. Nutrition indicators were tested by electrochemical luminescence.59.70% children were allergic to at least 1 allergen, comprising 24.90% to aeroallergen and 38.81% to food allergen, respectively, whereas 36.28% children were allergic to both aeroallergen and food allergen. Milk was the most common food allergen, and egg came in second place. With regard to aeroallergen, house dust mite held the maximum proportion (65.02%), whereas dust mite followed behind. Inhalation allergy was more commonly seen in boys than girls. Bronchitis was the most common symptom of both allergies. In addition, the highest incidence age for children to be sensitive to food allergen and aeroallergen were 0∼2 years' old and 3∼5 years' old, respectively. It is worth mentioning that there was no significant difference in nutritional status between children with or without allergic diseases.Our findings reveal that milk, egg, house dust mite, and dust mite are the most common allergens among children in Sichuan province. Boys are more susceptible to aeroallergen than girls. Furthermore, the prevalence of ingestion and inhalation allergy varies from different age groups, and has no correlation with nutritional status. In brief, the analysis of the pattern of food allergen and aeroallergen sensitization is invaluable to effective diagnosis and treatment of allergic diseases.

Real-Life effects of benralizumab on exacerbation number and lung hyperinflation in atopic patients with severe eosinophilic asthma

BACKGROUND

The humanized monoclonal antibody benralizumab targets the α subunit of the interleukin-5 (IL-5) receptor and the FcγRIIIa receptor expressed by natural killer cells. Through this dual mechanism of action, benralizumab neutralizes the pro-eosinophil functions of IL-5 and promotes eosinophil apoptosis.

OBJECTIVES AND METHODS

The present real-life study aimed to evaluate, in 22 allergic patients with severe eosinophilic asthma, the effects of benralizumab on asthma exacerbations and lung hyperinflation.

RESULTS

In this regard here we show that, after 24 weeks of add-on treatment, benralizumab completely depleted peripheral blood eosinophils (from 810 to 0 cells/μL; p < 0.0001), and significantly decreased both asthma exacerbation number (from 4 to 0; p < 0.0001) and residual volume (from 2720 to 2300 mL; p < 0.01). Moreover, at the same time point (24 weeks) benralizumab also increased pre-bronchodilator FEV₁ (from 1295 to 1985 mL; p < 0.0001), FVC (from 2390 to 2974 mL; p < 0.0001), FEF_25-75 (from 0.6 to 1.42 L/sec; p < 0.0001), IC (from 1940 to 2460 mL; not significant), and ACT score (from 14.73 to 22.95; p < 0.0001), as well as reduced prednisone intake (from 25 to 0 mg; p < 0.0001).

CONCLUSION

In conclusion, our results suggest that via its anti-eosinophil actions benralizumab improved airflow limitation, lung hyperinflation, and respiratory symptoms, as well as lowered asthma exacerbation rate and abrogated OCS consumption in most patients.

Real-life evaluation of mepolizumab efficacy in patients with severe eosinophilic asthma, according to atopic trait and allergic phenotype

BACKGROUND

Anti-interleukin-5 (IL-5) monoclonal antibodies can be used as add-on biological therapies in allergic and non-allergic patients with severe eosinophilic asthma. However, within such a therapeutic context real-life investigations are lacking.

OBJECTIVE

Therefore, the aim of the present observational study was to evaluate the effects of mepolizumab in allergic and non-allergic subjects with severe eosinophilic asthma.

METHODS

Relevant clinical, functional, laboratory, and pharmacotherapeutic parameters were assessed in the above patient subgroups.

RESULTS

After one year of add-on biological treatment with mepolizumab, our 88 patients experienced a remarkable improvement of their severe asthma, documented by a better symptom control, expressed by a significant improvement in asthma control test (ACT) score. Indeed, the mean value (±standard deviation) of ACT score increased from 12.55 (±3.724) to 21.08 (±3.358). Moreover, significant improvements were also detected with regard to the median values (interquartile range) of forced expiratory volume in one second (FEV₁ ), blood eosinophil numbers, annual rate of disease exacerbations, and daily intake of oral corticosteroids (OCS). In particular, FEV₁ enhanced from 1640 mL (1110-2275) to 1920 mL (1525-2615), blood eosinophil count dropped from 711.0 cells/μL (500.0-1022) to 90.00 cells/μL (50.00-117.5), the annual rate of asthma exacerbations decreased from 3.000 (2.000-6.000) to 0.000 (0.000-1.000), and the daily prednisone intake fell from 6.250 mg (0.000-25.00) to 0.000 mg (0.000-0.000). After one year of mepolizumab treatment, the improvements in clinical, functional, and haematological parameters were quite similar in patient subgroups characterized by skin prick test (SPT) negativity or positivity, respectively. A significant correlation was observed between serum IgE levels and OCS intake decrease (r = -0.2257; P < .05).

CONCLUSION AND CLINICAL RELEVANCE

Hence, our real-life data suggest that mepolizumab can represent a valid add-on therapeutic option for patients with severe eosinophilic asthma, irrespective of IgE serum concentrations, and allergic sensitization.

Risk Factors for Safety of Allergen-Specific Sublingual Immunotherapy in Children with Allergic Rhinitis

A good compliance often attributes to good efficacy and safety of sublingual immunotherapy (SLIT). However, few studies have been conducted on the safety of SLIT treatment in children. We aimed to confirm the pretreatment parameters to predict the safety in children who underwent SLIT. 601 children with allergic rhinitis (AR) treated with SLIT were enrolled in this study. Baseline clinical information and laboratory parameters were collected. The clinical response and adverse events (AEs) were recorded and evaluated. A multivariate logistic regression model was established to confirm the predictors for AEs. The AEs were reported in 75 children (13.8%). The serum-specific IgE (s-IgE) level was significantly correlated with the occurrence of AEs by multivariate logistic regression analysis. Our receiver operating characteristic (ROC) analysis of the serum s-IgE levels &#x3e;21.6 IU/mL had the best sensitivity (83.7%) and specificity (76.7%) to predict safety. The serum s-IgE level was significantly correlated with safety of SLIT in children, which may be helpful for patient selection before SLIT.

Omalizumab lowers asthma exacerbations, oral corticosteroid intake and blood eosinophils: Results of a 5-YEAR single-centre observational study

Omalizumab is a humanized monoclonal antibody which binds to human immunoglobulins E (IgE), thus preventing their interactions with both high affinity and low affinity IgE receptors. Therefore, omalizumab is currently recommended for add-on biological therapy of uncontrolled allergic asthma, mainly characterized by type 2 airway eosinophilic inflammation. Because omalizumab has been the first, and for a long time the only available monoclonal antibody for add-on treatment of type 2 asthma, some long-term studies have been published which provide a clear evidence of the therapeutic effectiveness of the anti-IgE pharmacological strategy. Within this context, the present single-centre observational study refers to 15 patients with severe allergic asthma, treated with omalizumab for at least 5 years at the Respiratory Unit of "Magna Græcia" University Hospital located in Catanzaro, Italy. In these asthmatic subjects we observed significant increases in asthma control test (ACT) score, with respect to baseline (14.60 ± 2.97), after 1 year (19.20 ± 2.98; p < 0.0001) and 5 years (21.67 ± 2.38; p < 0.0001) of add-on treatment with omalizumab. More importantly, omalizumab significantly lowered the number of annual asthma exacerbations (baseline: 3.66 ± 2.01) after 1 year (0.83 ± 1.14; p < 0.0001) and 5 years (0.63 ± 0.99; p < 0.0001), respectively. This excellent therapeutic outcome made it possible to drastically decrease the daily oral intake of prednisone (baseline: 22.50 ± 5.17 mg) after 1 year (1.83 ± 4.06 mg; p < 0.0001), as well as after 5 years (1.66 ± 3.61 mg; p < 0.0001). With regard to lung function, omalizumab significantly and persistently enhanced FEV₁ (baseline: 1636 ± 628.4 mL) after 1 year (2000 ± 679.7 mL; p < 0.05) and 5 years (1929 ± 564.8 mL; p < 0.05), respectively. Such relevant clinical and functional improvements were associated with reductions of blood eosinophil counts (baseline: 646.0 ± 458.9 cells/μl), already detectable after 1 year (512.7 ± 327.8 cells/μl; not significant), which reached the threshold of statistical significance after 5 years (326.0 ± 171.8 cells/μl; p < 0.05). Therefore, these real-life data referring to our single-centre observational investigation further corroborate the long-term therapeutic ability of omalizumab to improve several clinical, functional and haematological signatures of severe type 2 asthma.

Benralizumab: From the Basic Mechanism of Action to the Potential Use in the Biological Therapy of Severe Eosinophilic Asthma

Asthma is a very frequent chronic airway disease that includes many different clinical phenotypes and inflammatory patterns. In particular, eosinophilic bronchial inflammation is often associated with allergic as well as nonallergic asthma. The most important cytokine involved in the induction, maintenance, and amplification of airway eosinophilia in asthma is interleukin-5 (IL-5), released by both T helper 2 (Th2) lymphocytes and group 2 innate lymphoid cells (ILC2). Hence, IL-5 and its receptor are suitable targets for selective biologic drugs which can play a key role in add-on treatment of severe eosinophilic asthma refractory to corticosteroids. Within such a context, the anti-IL-5 monoclonal antibodies mepolizumab and reslizumab have been developed and approved for biological therapy of uncontrolled eosinophilic asthma. In this regard, on the basis of several successful randomized controlled trials, the anti-IL-5 receptor benralizumab has also recently obtained the approval from US Food and Drug Administration (FDA).

Omalizumab, the first available antibody for biological treatment of severe asthma: more than a decade of real-life effectiveness

Omalizumab was the first, and for a long time the only available monoclonal antibody for the add-on treatment of severe allergic asthma. In particular, omalizumab selectively targets human immunoglobulin (Ig)E, forming small-size immune complexes that inhibit IgE binding to its high- and low-affinity receptors. Therefore, omalizumab effectively blunts the immune response in atopic asthmatic patients, thus significantly improving the control of asthma symptoms and successfully preventing disease exacerbations. These very positive effects of omalizumab make it possible to drastically decrease both referrals to the emergency room and hospitalizations for asthma exacerbations. Such important therapeutic actions of omalizumab have been documented by several randomized clinical trials, and especially by more than 10 years of real-life experience in daily clinical practice. Omalizumab can also interfere with airway remodelling by inhibiting the activation of IgE receptors located on structural cells such as bronchial epithelial cells and airway smooth muscle cells. Moreover, omalizumab is characterized by a very good safety and tolerability profile. Hence, omalizumab represents a valuable therapeutic option for the add-on biological treatment of severe allergic asthma.