Novel immunotherapeutic approaches for allergy and asthma

The lncRNA PVT1/miR-590-5p/FSTL1 axis modulates the proliferation and migration of airway smooth muscle cells in asthma

OBJECTIVE

Asthma is a prevalent chronic inflammatory airway disease that is characterised by airway remodelling and airway hyperresponsiveness. Abnormal proliferation and migration of airway smooth muscle cells (ASMCs) contribute to airway remodelling in asthma. However, the molecular mechanism underlying an increased ASMC mass in asthma remains elusive. Herein, we aimed at investigating the regulation of lncRNA PVT1 on ASMCs and focussing on the mechanism in the proliferation and migration.

METHODS

Expression levels of lncRNA PVT1 and miR-590-5p in the serum collected from 24 children with asthma and 10 control children were determined by qRT-PCR. ASMCs proliferation and migration prior to and post platelet-derived growth factor subunit B (PDGF-BB) stimulation were examined by CCK-8 test and transwell assay. Dual-luciferase reporter assay was performed to determine miR-590-5p interaction with lncRNA PVT1 and follistatin-like 1 (FSTL1). Expression of lncRNA PVT1, miR-590-5p, FSTL1, C-Myc, cyclin D1, and cyclin-dependent kinase 1 (CDK1) was tested by quantitative real-time PCR (qRT-PCR) and immunoblotting analysis.

RESULTS

The expression level of lncRNA PVT1 was higher but the expression level of miR-590-5p was lower in the serum of children with asthma than in control children. The expression level of lncRNA PVT1 was negatively correlated with the expression level of miR-590-5p in asthma. LncRNA PVT1 was upregulated upon PDGF-BB stimulation. LncRNA PVT1 knockdown by its specific shRNA repressed PDGF-BB-induced promotion of proliferation and migration in ASMCs and triggered an elevated miR-590-5p along with declined C-Myc, cyclin D1, and CDK1. The effects of lncRNA PVT1 knockdown on PDGF-BB-induced ASMCs were lost upon miR-590-5p inhibition. MiR-590-5p targeted FSTL1 gene and declined its expression, thus suppressing ASMC proliferation and migration following PDGF-BB stimulation and downregulating C-Myc, cyclin D1, and CDK1 expressions. The effects of miR-590-5p on PDGF-BB-induced ASMCs were lost upon FSTL1 overexpression.

CONCLUSION

These results support the notion that the lncRNA PVT1/miR-590-5p/FSTL1 axis modulates ASMCs proliferation and migration following PDGF-BB stimulation, providing a potential therapeutic target to attenuate airway remodelling in asthma.

Principles of Allergen Immunotherapy and Its Clinical Application in China: Contrasts and Comparisons with the USA

Allergen immunotherapy (AIT) for allergic rhinitis (AR), asthma, and other allergic diseases has developed quickly. House dust mite (HDM), Artemisia (wormwood), Humulus japonicus (Japanese hop), Alternaria alternata, and Cladosporium herbarum are the five most common inhalant allergens in China. AIT has been performed in China for over 60 years. With the support of the Chinese Medical Association (CMA) and the Chinese Medical Doctors Association (CMDA), the Chinese College of Allergy and Asthma (CCAA) was established in 2016 as a specialized branch of CDMA and is the main certification authority for AIT. Chinese allergists and scientists have made tremendous progress in the development of AIT. There have been many publications by Chinese allergists and scientists worldwide encompassing original research studies, systematic reviews, case studies, and clinical trials. Currently, conventional subcutaneous immunotherapy (SCIT) is the preferred AIT in China, but sublingual immunotherapy (SLIT) is beginning to gain recognition. An increasing number of clinical trials have been conducted to investigate the clinical efficacy and side effects of SLIT and SCIT. In China, HDM is the only commercial standardized allergen extracts in clinical use, whereas the others are crude allergen extracts. Besides standardized allergen extracts, other forms of hypoallergenic extracts are still being investigated and developed in China. Immunotherapy in China is similar to that in the USA in which allergen extracts can be mixed for SCIT. However, allergen extracts cannot be mixed for SCIT in Europe.

Human dendritic cell DC-SIGN and TLR-2 mediate complementary immune regulatory activities in response to Lactobacillus rhamnosus JB-1

The microbiota is required for optimal host development and ongoing immune homeostasis. Lactobacilli are common inhabitants of the mammalian large intestine and immunoregulatory effects have been described for certain, but not all, strains. The mechanisms underpinning these protective effects are beginning to be elucidated. One such protective organism is Lactobacillus rhamnosus JB-1 (Lb. rhamnosus JB-1). Lb. murinus has no such anti-inflammatory protective effects and was used as a comparator organism. Human monocyte-derived dendritic cells (MDDCs) were co-incubated with bacteria and analysed over time for bacterial adhesion and intracellular processing, costimulatory molecule expression, cytokine secretion and induction of lymphocyte polarization. Neutralising antibodies were utilized to identify the responsible MDDC receptors. Lb. rhamnosus JB-1 adhered to MDDCs, but internalization and intracellular processing was significantly delayed, compared to Lb. murinus which was rapidly internalized and processed. Lb. murinus induced CD80 and CD86 expression, accompanied by high levels of cytokine secretion, while Lb. rhamnosus JB-1 was a poor inducer of costimulatory molecule expression and cytokine secretion. Lb. rhamnosus JB-1 primed MDDCs induced Foxp3 expression in autologous lymphocytes, while Lb. murinus primed MDDCs induced Foxp3, T-bet and Ror-γt expression. DC-SIGN was required for Lb. rhamnosus JB-1 adhesion and influenced IL-12 secretion, while TLR-2 influenced IL-10 and IL-12 secretion. Here we demonstrate that the delayed kinetics of bacterial processing by MDDCs correlates with MDDC activation and stimulation of lymphocytes. Thus, inhibition or delay of intracellular processing may be a novel strategy by which certain commensals may avoid the induction of proinflammatory responses.

Experimental hookworm infection and gluten microchallenge promote tolerance in celiac disease

BACKGROUND

Celiac disease (CeD) is a common gluten-sensitive autoimmune enteropathy. A gluten-free diet is an effective treatment, but compliance is demanding; hence, new treatment strategies for CeD are required.

OBJECTIVE

Parasitic helminths hold promise for treating inflammatory disorders, so we examined the influence of experimental hookworm infection on the predicted outcomes of escalating gluten challenges in CeD subjects.

METHODS

A 52-week study was conducted involving 12 adults with diet-managed CeD. Subjects were inoculated with 20 Necator americanus larvae, and escalating gluten challenges consumed as pasta were subsequently administered: (1) 10 to 50 mg for 12 weeks (microchallenge); (2) 25 mg daily + 1 g twice weekly for 12 weeks (GC-1g); and (3) 3 g daily (60-75 straws of spaghetti) for 2 weeks (GC-3g). Symptomatic, serologic, and histological outcomes evaluated gluten toxicity. Regulatory and inflammatory T cell populations in blood and mucosa were examined.

RESULTS

Two gluten-intolerant subjects were withdrawn after microchallenge. Ten completed GC-1g, 8 of whom enrolled in and completed GC-3g.

PRIMARY OUTCOMES

median villous height-to-crypt depth ratios (2.60-2.63; P = .98) did not decrease as predicted after GC-1g, and the mean IgA-tissue transglutaminase titers declined, contrary to the predicted rise after GC-3g.

SECONDARY OUTCOMES

quality of life scores improved (46.3-40.6; P = .05); celiac symptom indices (24.3-24.3; P = .53), intra-epithelial lymphocyte percentages (32.5-35.0; P = .47), and Marsh scores were unchanged by gluten challenge. Intestinal T cells expressing IFNγ were reduced following hookworm infection (23.9%-11.5%; P = .04), with corresponding increases in CD4(+) Foxp3(+) regulatory T cells (0.19%-1.12%; P = .001).

CONCLUSIONS

Necator americanus and gluten microchallenge promoted tolerance and stabilized or improved all tested indices of gluten toxicity in CeD subjects.

Amelioration of ovalbumin-induced allergic airway disease following Der p 1 peptide immunotherapy is not associated with induction of IL-35

In the present study, we show therapeutic amelioration of established ovalbumin (OVA)-induced allergic airway disease following house dust mite (HDM) peptide therapy. Mice were sensitized and challenged with OVA and HDM protein extract (Dermatophagoides species) to induce dual allergen sensitization and allergic airway disease. Treatment of allergic mice with peptides derived from the major allergen Der p 1 suppressed OVA-induced airway hyperresponsiveness, tissue eosinophilia, and goblet cell hyperplasia upon rechallenge with allergen. Peptide treatment also suppressed OVA-specific T-cell proliferation. Resolution of airway pathophysiology was associated with a reduction in recruitment, proliferation, and effector function of T(H)2 cells and decreased interleukin (IL)-17⁺ T cells. Furthermore, peptide immunotherapy induced the regulatory cytokine IL-10 and increased the proportion of Fox p3⁺ cells among those expressing IL-10. Tolerance to OVA was not associated with increased IL-35. In conclusion, our results provide in vivo evidence for the creation of a tolerogenic environment following HDM peptide immunotherapy, leading to the therapeutic amelioration of established OVA-induced allergic airway disease.

Effectiveness of subcutaneous versus sublingual immunotherapy for the treatment of allergic rhinoconjunctivitis and asthma: a systematic review

BACKGROUND

Allergen-specific immunotherapy is widely used in the management of patients with allergic rhinoconjunctivitis and asthma, but the best route of delivery is unclear.

OBJECTIVE

We performed a systematic review of studies with head-to-head comparison of effectiveness and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) in the treatment of allergic rhinoconjunctivitis and asthma.

METHODS

MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were searched through December 21, 2012. We included English language randomized controlled trials that enrolled patients with allergic rhinoconjunctivitis and/or asthma with head-to-head comparisons of SCIT with SLIT. Paired reviewers extracted detailed information from included articles on standardized forms and assessed the risk of bias in each article.

RESULTS

Eight trials compared the effectiveness and safety of SCIT and SLIT. The effectiveness of the 2 forms of immunotherapy in managing allergic asthma and rhinoconjunctivitis were reported in 4 and 6 clinical trials, respectively. Low-grade evidence supports greater effectiveness of SCIT than SLIT for asthma symptom reduction and also at reducing a combined measure of rhinitis symptoms and medication use. Moderate-grade evidence supports greater effectiveness of SCIT than SLIT for nasal and/or eye symptom reduction. All 8 trials reported on adverse events with an episode of anaphylaxis reported in a child treated with SCIT.

CONCLUSION

Our review provides low-grade evidence to support that SCIT is superior to SLIT for reduction in asthma symptoms and moderate-grade evidence for reduction of allergic rhinoconjunctivitis. Additional studies are required to strengthen this evidence base for clinical decision making.

Nanoparticulate adjuvants and delivery systems for allergen immunotherapy

In the last decades, significant progress in research and clinics has been made to offer possible innovative therapeutics for the management of allergic diseases. However, current allergen immunotherapy shows limitations concerning the long-term efficacy and safety due to local side effects and risk of anaphylaxis. Thus, effective and safe vaccines with reduced dose of allergen have been developed using adjuvants. Nevertheless, the use of adjuvants still has several disadvantages, which limits its use in human vaccines. In this context, several novel adjuvants for allergen immunotherapy are currently being investigated and developed. Currently, nanoparticles-based allergen-delivery systems have received much interest as potential adjuvants for allergen immunotherapy. It has been demonstrated that the incorporation of allergens into a delivery system plays an important role in the efficacy of allergy vaccines. Several nanoparticles-based delivery systems have been described, including biodegradable and nondegradable polymeric carriers. Therefore, this paper provides an overview of the current adjuvants used for allergen immunotherapy. Furthermore, nanoparticles-based allergen-delivery systems are focused as a novel and promising strategy for allergy vaccines.

Regulation of the immune response and inflammation by histamine and histamine receptors

Histamine is a biogenic amine with extensive effects on many cell types, including important immunologic cells, such as antigen-presenting cells, natural killer cells, epithelial cells, and T and B lymphocytes. Histamine and its 4 receptors represent a complex system of immunoregulation with distinct effects dependent on receptor subtypes and their differential expression. These are influenced by the stage of cell differentiation, as well as microenvironmental influences, leading to the selective recruitment of effector cells into tissue sites accompanied by effects on cellular maturation, activation, polarization, and effector functions, which lead to tolerogenic or proinflammatory responses. In this review we discuss the regulation of histamine secretion, receptor expression, and differential activation of cells within both the innate and adaptive immune responses. It is clear that the effects of histamine on immune homeostasis are dependent on the expression and activity of the 4 currently known histamine receptors, and we also recognize that 100 years after the original identification of this biogenic amine, we still do not fully understand the complex regulatory interactions between histamine and the host immune response to everyday microbial and environmental challenges.

Specific immunotherapy and turning off the T cell: how does it work?

OBJECTIVE

To examine T-regulatory (Treg) cell functions in allergic immune responses and their roles during allergen specific immunotherapy based on recent developments and current understanding of immune regulation.

DATA SOURCES

PubMed search of English-language articles regarding Treg cells and allergen specific immunotherapy.

STUDY SELECTION

Articles on the subject matter were selected and reviewed.

RESULTS

Allergen specific immunotherapy is the ultimate treatment modality targeting the immunopathogenic mechanisms of allergic disorders. A diminished allergen-specific T-cell proliferation and suppressed secretion of T(H)1- and T(H)2-type cytokines are the characteristic hallmarks. In addition, Treg cells inhibit the development of allergen-specific T(H)2 and T(H)1 cell responses and therefore exert key roles in healthy immune response to allergens. Treg cells potently suppress IgE production and directly or indirectly control the activity of effector cells of allergic inflammation, such as eosinophils, basophils, and mast cells.

CONCLUSION

As advancements in the field of allergen specific immunotherapy ensue, they may provide novel progression of more rational and safer approaches for the prevention and treatment of allergic disorders. Currently, the Treg cell field is an open research area to increase our understanding in mechanisms of peripheral tolerance to allergens.