Mechanisms of peripheral tolerance to allergens

The joint effect of cumulative doses for outdoor air pollutants exposure in early life on asthma and wheezing among young children

BACKGROUND

Constrained by no proper way to assess cumulative exposure, the joint effect of air pollution cumulative exposure doses on childhood asthma and wheezing (AW) was not understood.

OBJECTIVE

To assess the association between cumulative exposure to multiple air pollutants in early life and childhood AW.

METHODS

We designed a nested case-control study based on the birth cohort in Jinan City. Children with AW followed up within 2 years after birth were treated as cases, and non-cases in this cohort were treated as the control source population, and the propensity score matching method was used to match each case to 5 controls. We calculated the individual cumulative outdoor exposure doses for each period using an inverse distance weighted model, alongside the complex Simpson's formula, accounting for outdoor time and respiratory volume. The Least absolute shrinkage and selection operator (Lasso) regression was performed to screen for covariates. To analyze the joint effects of pollutants, we employed the weighted quantile sum (WQS) regression model in conjunction with conditional logistic regression.

RESULTS

84 cases and 420 controls were included in this study. The odds ratio (OR) with 95% confidence interval (CI) of the impact of cumulative exposure (mg/m3) after birth on childhood AW was 1.78 (1.15-2.74) for SO2, 1.69 (1.11-2.57) for NO2, and 1.65 (1.09-2.52) for PM2.5, respectively. Furthermore, with each 25th percentile increase in the WQS index, the overall risk of cumulative doses for six pollutants exposure after birth on AW increased by an adjusted OR of 1.10 (1.03, 1.18), and SO2, PM2.5, and NO2 contributed the most to the WQS index. However, no statistically significant association was found between cumulative exposure to all pollutants before birth and childhood AW.

CONCLUSIONS

There was a joint effect of the cumulative exposure dose of outdoor air pollutants after birth on AW in children aged 0-2 years. And traffic-related pollutants (SO2, PM2.5, and NO2) make a greater contribution to the joint effect.

Characterisation of macrophage infiltration and polarisation based on integrated transcriptomic and histological analyses in Primary Sjögren's syndrome

Background

Primary Sjögren's syndrome (pSS) is a progressive inflammatory autoimmune disease. Immune cell infiltration into glandular lobules and ducts and glandular destruction are the pathophysiological hallmarks of pSS. Macrophages are one of the most important cells involved in the induction and regulation of an inflammatory microenvironment. Although studies have reported that an abnormal tissue microenvironment alters the metabolic reprogramming and polarisation status of macrophages, the mechanisms driving macrophage infiltration and polarisation in pSS remain unclear.

Methods

Immune cell subsets were characterised using the single-cell RNA sequencing (scRNA-seq) data of peripheral blood mononuclear cells (PBMCs) from patients with pSS (n = 5) and healthy individuals (n = 5) in a public dataset. To evaluate macrophage infiltration and polarisation in target tissues, labial salivary gland biopsy tissues were subjected to histological staining and bulk RNA-seq (pSS samples, n = 24; non-pSS samples, n = 12). RNA-seq data were analysed for the construction of macrophage co-expression modules, enrichment of biological processes and deconvolution-based screening of immune cell types.

Results

Detailed mapping of PBMCs using scRNA-seq revealed five major immune cell subsets in pSS, namely, T cells, B cells, natural killer (NK) cells, dendritic cells (DCs) and monocyte-macrophages. The monocyte-macrophage subset was large and had strong inflammatory gene signatures. This subset was found to play an important role in the generation of reactive oxygen species and communicate with other innate and adaptive immune cells. Histological staining revealed that the number of tissue-resident macrophages was high in damaged glandular tissues, with the cells persistently surrounding the tissues. Analysis of RNA-seq data using multiple algorithms demonstrated that the high abundance of pro-inflammatory M1 macrophages was accompanied by the high abundance of other infiltrating immune cells, senescence-associated secretory phenotype and evident metabolic reprogramming.

Conclusion

Macrophages are among the most abundant innate immune cells in PBMCs and glandular tissues in patients with pSS. A bidirectional relationship exists between macrophage polarisation and the inflammatory microenvironment, which may serve as a therapeutic target for pSS.

Mechanisms of climate change and related air pollution on the immune system leading to allergic disease and asthma

Climate change is considered the greatest threat to global health. Greenhouse gases as well as global surface temperatures have increased causing more frequent and intense heat and cold waves, wildfires, floods, drought, altered rainfall patterns, hurricanes, thunderstorms, air pollution, and windstorms. These extreme weather events have direct and indirect effects on the immune system, leading to allergic disease due to exposure to pollen, molds, and other environmental pollutants. In this review, we will focus on immune mechanisms associated with allergy and asthma-related health risks induced by climate change events. We will review current understanding of the molecular and cellular mechanisms by which the changing environment mediates these effects.

Mast cells-fetal mast cells crosstalk with maternal interfaces during pregnancy: Friend or foe?

Mast cells (MC) are hematopoietic immune cells that play a major role during allergic reactions in adults by releasing a myriad of vasoactive and inflammatory mediators. MC seed all vascularized tissues and are most prominent in organs with a barrier function such as skin, lungs, and intestines. These secreted molecules cause mild symptoms such as localized itchiness and sneezing to life-threatening symptoms (i.e., anaphylactic shock). Presently, despite the extensive research on Th2-mediated immune responses in allergic diseases in adults, we are still unable to determine the mechanisms of the role of MC in developing pediatric allergic (PA) disorders. In this review, we will summarize the most recent findings on the origin of MC and discuss the underappreciated contribution of MC in the sensitization phase to maternal antibodies during pregnancy in allergic reactions and other diseases such as infectious diseases. Then, we will lay out potential MC-dependent therapeutic strategies to be considered in future investigations to understand the remaining gaps in MC research for a better quality of life for these young patients.

Impact of the mucosal milieu on antibody responses to allergens

Respiratory and digestive mucosal surfaces are continually exposed to common environmental antigens, which include potential allergens. Although innocuous in healthy individuals, allergens cause allergy in predisposed subjects and do so by triggering a pathologic T_H2 cell response that induces IgE class switching and somatic hypermutation in allergen-specific B cells. The ensuing affinity maturation and plasma cell differentiation lead to the abnormal release of high-affinity IgE that binds to powerful FcεRI receptors on basophils and mast cells. When cross-linked by allergen, FcεRI-bound IgE instigates the release of prestored and de novo-induced proinflammatory mediators. Aside from causing type I hypersensitivity reactions underlying allergy, IgE affords protection against nematodes or venoms from insects and snakes, which raises questions as to the fundamental differences between protective and pathogenic IgE responses. In this review, we discuss the impact of the mucosal environment, including the epithelial and mucus barriers, on the induction of protective IgE responses against environmental antigens. We further discuss how perturbations of these barriers may contribute to the induction of pathogenic IgE production.

Microbial Dysbiosis Tunes the Immune Response Towards Allergic Disease Outcomes

The hygiene hypothesis has been popularized as an explanation for the rapid increase in allergic disease observed over the past 50 years. Subsequent epidemiological studies have described the protective effects that in utero and early life exposures to an environment high in microbial diversity have in conferring protective benefits against the development of allergic diseases. The rapid advancement in next generation sequencing technology has allowed for analysis of the diverse nature of microbial communities present in the barrier organs and a determination of their role in the induction of allergic disease. Here, we discuss the recent literature describing how colonization of barrier organs during early life by the microbiota influences the development of the adaptive immune system. In parallel, mechanistic studies have delivered insight into the pathogenesis of disease, by demonstrating the comparative effects of protective T regulatory (Treg) cells, with inflammatory T helper 2 (Th2) cells in the development of immune tolerance or induction of an allergic response. More recently, a significant advancement in our understanding into how interactions between the adaptive immune system and microbially derived factors play a central role in the development of allergic disease has emerged. Providing a deeper understanding of the symbiotic relationship between our microbiome and immune system, which explains key observations made by the hygiene hypothesis. By studying how perturbations that drive dysbiosis of the microbiome can cause allergic disease, we stand to benefit by delineating the protective versus pathogenic aspects of human interactions with our microbial companions, allowing us to better harness the use of microbial agents in the design of novel prophylactic and therapeutic strategies.

Mechanisms of allergen immunotherapy supporting its disease-modifying effect

Allergen immunotherapy (AIT) is considered the only disease-modifying treatment available at present for allergic disorders. Its main benefits include improvement of symptoms, decreased need for pharmacotherapy, prevention of new sensitizations and sustained effect after AIT completion. The key pillars of AIT-induced tolerance include a shift from Th2 to Th1 response, an increase of regulatory T and B cells, pro-inflammatory effector cell downregulation and IgE suppression, in addition to IgG4, IgA and IgD induction. AIT may also induce trained immunity, characterized by a durable decrease in group 2 of innate lymphoid cells (ILCs) and increased ILC1 and ILC3s. Understanding the immune mechanisms of AIT is essential for validating biomarkers for the prediction of AIT response and for achieving AIT success.

Allergic Diseases: A Comprehensive Review on Risk Factors, Immunological Mechanisms, Link with COVID-19, Potential Treatments, and Role of Allergen Bioinformatics

The prevalence of allergic diseases is regarded as one of the key challenges in health worldwide. Although the precise mechanisms underlying this rapid increase in prevalence are unknown, emerging evidence suggests that genetic and environmental factors play a significant role. The immune system, microbiota, viruses, and bacteria have all been linked to the onset of allergy disorders in recent years. Avoiding allergen exposure is the best treatment option; however, steroids, antihistamines, and other symptom-relieving drugs are also used. Allergen bioinformatics encompasses both computational tools/methods and allergen-related data resources for managing, archiving, and analyzing allergological data. This study highlights allergy-promoting mechanisms, algorithms, and concepts in allergen bioinformatics, as well as major areas for future research in the field of allergology.

Favorable prognosis of vaccine-associated immune thrombocytopenia in children is correlated with young age at vaccination: Retrospective survey of a nationwide disease registry

Childhood vaccine-associated immune thrombocytopenia (ITP) has a mostly favorable prognosis. To identify factors associated with prognosis, a retrospective survey was conducted with children with ITP who were registered in the Japanese Society of Pediatric Hematology/Oncology registry from 2008 to 2011. A total of 477 patients were categorized into four groups by event preceding ITP onset: vaccine-precedence (VP; n = 43), vaccine/infection-precedence (VIP; n = 34), infection-precedence (IP; n = 162), and no vaccine/infection-precedence (NVI; n = 238). Compared to IP and NVI, VP and VIP were significantly younger at diagnosis, with the age distribution peaking at infancy, and more frequently had favorable prognosis. Time to platelet recovery to 100 × 10³/µL was significantly faster for VP and VIP than NVI. Multivariate Cox regression analysis with sex, age at diagnosis, infection-precedence, and vaccine-precedence as variables revealed age < 36 months (HR 0.992, 95% CI 0.989-0.995; p < 0.001) and male sex (HR 0.770, 95% CI 0.623-0.952; p = 0.015) as associated factors, but not infection-precedence (p = 0.149) or vaccine-precedence (p = 0.650). In subgroup analysis in patients < 36 months, age at diagnosis (p < 0.001) was the only associated factor. Favorable prognosis of childhood vaccine-associated ITP is correlated with young age at vaccination, but not with vaccination itself.

Subjects develop tolerance to Pru p 3 but respiratory allergy to Pru p 9: A large study group from a peach exposed population

Peach tree allergens are present in fruit, pollen, branches, and leaves, and can induce systemic, respiratory, cutaneous, and gastrointestinal symptoms. We studied the capacity of peach fruit/Pru p 1, Pru p 3, Pru p 4, Pru p 7 and peach pollen/Pru p 9 for inducing symptoms following oral or respiratory exposure in a large group of subjects. We included 716 adults (aged 21 to 83 y.o.) exposed to peach tree pollen and fruit intake in the study population. Participants completed a questionnaire and were skin tested with a panel of inhalant and food allergens, including peach tree pollen, Pru p 9 and peach fruit skin extract. Immunoglobulin E antibodies (SIgE) to Pru p 1, Pru p 3, Pru p 4 and Pru p 7 were quantified. Sensitised subjects underwent oral food challenge with peach fruit and nasal provocation test with peach tree pollen and Pru p 9. The prevalence of sensitisation to peach fruit was 5% and most of these had SIgE to Pru p 3, with a very low proportion to Pru p 4 SIgE and no SIgE to Pru p 1 and Pru p 7. In only 1.8%, anaphylaxis was the clinical entity induced. Cases with positive skin tests to peach and SIgE to Pru p 3 presented a good tolerance after oral challenge with peach fruit. The prevalence of skin sensitisation to peach tree pollen was 22%, with almost half recognising Pru p 9. This induced respiratory symptoms in those evaluated by nasal provocation. In a large population group exposed to peach fruit and peach tree pollen, most individuals were tolerant, even in those with SIgE to Pru p 3. A positive response to Pru p 9 was associated with respiratory allergy.

Hymenoptera Venom Immunotherapy: Immune Mechanisms of Induced Protection and Tolerance

Hymenoptera venom allergy is one of the most severe allergic diseases, with a considerable prevalence of anaphylactic reaction, making it potentially lethal. In this review, we provide an overview of the current knowledge and recent findings in understanding induced immune mechanisms during different phases of venom immunotherapy. We focus on protection mechanisms that occur early, during the build-up phase, and on the immune tolerance, which occurs later, during and after Hymenoptera venom immunotherapy. The short-term protection seems to be established by the early desensitization of mast cells and basophils, which plays a crucial role in preventing anaphylaxis during the build-up phase of treatment. The early generation of blocking IgG antibodies seems to be one of the main reasons for the lower activation of effector cells. Long-term tolerance is reached after at least three years of venom immunotherapy. A decrease in basophil responsiveness correlates with tolerated sting challenge. Furthermore, the persistent decline in IgE levels and, by monitoring the cytokine profiles, a shift from a Th2 to Th1 immune response, can be observed. In addition, the generation of regulatory T and B cells has proven to be essential for inducing allergen tolerance. Most studies on the mechanisms and effectiveness data have been obtained during venom immunotherapy (VIT). Despite the high success rate of VIT, allergen tolerance may not persist for a prolonged time. There is not much known about immune mechanisms that assure long-term tolerance post-therapy.

Update on food allergy

Food allergy is a major public health issue with growing prevalence in the urbanized world and significant impact on the lives of allergic patients and their families. Research into the risk factors that have contributed to this increase and their underlying immune mechanisms could lead us to definitive ways for treatment and prevention of food allergy. For the time being, introduction of peanut and other allergenic foods in the diet at the time of weaning seems to be an effective way to prevent the development of food allergy. Improved diagnosis and appropriate management and support of food allergic patients are central to patient care with food immunotherapy and biologics making the transition to clinical practice. With the new available treatments, it is becoming increasingly important to include patients' and family preferences to provide a management plan tailored to their needs.

Antigen presentation between T cells drives Th17 polarization under conditions of limiting antigen

T cells form immunological synapses with professional antigen-presenting cells (APCs) resulting in T cell activation and the acquisition of peptide antigen-MHC (pMHC) complexes from the plasma membrane of the APC. They thus become APCs themselves. We investigate the functional outcome of T-T cell antigen presentation by CD4 T cells and find that the antigen-presenting T cells (Tpres) predominantly differentiate into regulatory T cells (Treg), whereas T cells that have been stimulated by Tpres cells predominantly differentiate into Th17 pro-inflammatory cells. Using mice deficient in pMHC uptake by T cells, we show that T-T antigen presentation is important for the development of experimental autoimmune encephalitis and Th17 cell differentiation in vivo. By varying the professional APC:T cell ratio, we can modulate Treg versus Th17 differentiation in vitro and in vivo, suggesting that T-T antigen presentation underlies proinflammatory responses in conditions of antigen scarcity.

Novel method to analyze cell kinetics for the rapid diagnosis and determination of the causative agent in allergy

Drug-induced allergy (DIA), an unexpectedly triggered side effect of drugs used for therapeutic purposes, is a serious clinical issue that needs to be resolved because it interrupts the treatment of the primary disease. Since conventional allergy testing is insufficient to accurately predict the occurrence of DIA or to determine the drugs causing it, the development of diagnostic and predictive tools for allergic reactions is important. We demonstrated a novel method, termed high-sensitive allergy test (HiSAT), for the rapid diagnosis of allergy (within 1 hr; with true-positive diagnosis rates of 89% and 9% for patients with and without allergy-like symptoms, respectively). HiSAT analyzes the cell kinetics as an index against chemotactic factors in a patient’s serum, as different from the diagnosis using conventional methods. Once allergy has occurred, HiSAT can be used to determine the causative medicine using culture supernatants incubated with the subject’s lymphocytes and the test allergen. This test is more efficient (60%) than the lymphocyte transformation test (20%). Furthermore, in HiSAT, cell mobility significantly increases in a dose-dependent manner against supernatant incubated with lymphocytes from a subject with pollinosis collected at a time when the subject is without allergic symptoms and the antigen. The result demonstraed that HiSAT might be a promising method to rapidly diagnose DIA or to determine with high accuracy the antigen causing allergy.

Granulocyte and monocyte adsorptive apheresis induces apoptosis of neutrophils and release of a novel chemoattractant for desensitization of interleukin-8 response - In vitro and in vivo results

OBJECTIVE

Apoptotic cells participate in maintenance of homeostasis of the adaptive immune system. Granulocyte/monocyte adsorptive apheresis (GMA) performed with an Adacolumn has been shown to have clinical efficacy together with immunomodulatory effects for immune-mediated disorder cases, such as inflammatory bowel disease (IBD) or psoriatic arthritis. Although induction of apoptosis in neutrophils by GMA has been observed, the detailed mechanism remains unclear.

METHODS

To focus on phagocytosis-induced cell death (PICD) that induces apoptotic neutrophils, a comparative study utilizing a GMA-carrier (leukocyte adsorbing carrier for Adacolumn) and yeast particles was performed with in vitro and in vivo examinations.

RESULTS

L-selectin was significantly (P = 0.0133) shed, reactive oxygen species (ROS) production was promoted (P = 0.0019), and apoptosis induction was enhanced (P = 0.0087) by peripheral blood co-cultured with the GMA-carrier or yeast particles as compared to incubated blood alone. Furthermore, degranulation of myeloperoxidase, elastase, and lactoferrin was increased by both treatments, while the highest level of interleukin-1 receptor antagonist release was found with GMA-carrier treatment (P = 0.0087) as compared to the yeast particles. Plasma from blood treated with the GMA-carrier showed chemotactic activity, and suppressed neutrophil migration to IL-8 and LTB₄. In vivo results demonstrated that neutrophil chemotaxis to IL-8 was desensitized (P = 0.0078) in rabbits following GMA apheresis, while CXCR1 and CXCR2 expressions in neutrophils were reduced by exposing peripheral blood to the GMA-carrier.

CONCLUSIONS

GMA may regulate the immune system in patients with an immune-mediated disorder by inducing a biological response of neutrophils with a PICD-like reaction.

The Benefits of Vitamin D Supplementation for Athletes: Better Performance and Reduced Risk of COVID-19

The COVID-19 pandemic is having major economic and personal consequences for collegiate and professional sports. Sporting events have been canceled or postponed, and even when baseball and basketball seasons resumed in the United States recently, no fans were in attendance. As play resumed, several players developed COVID-19, disrupting some of the schedules. A hypothesis now under scientific consideration is that taking vitamin supplements to raise serum 25-hydroxyvitamin D [25(OH)D] concentrations could quickly reduce the risk and/or severity of COVID-19. Several mechanisms have been identified through which vitamin D could reduce the risks of infection and severity, death, and long-haul effects of COVID-19: (1) inducing production of cathelicidin and defensins to reduce the survival and replication of the SARS-CoV-2 virus; (2) reducing inflammation and the production of proinflammatory cytokines and risk of the "cytokine storm" that damages the epithelial layer of the lungs, heart, vascular system, and other organs; and (3) increasing production of angiotensin-converting enzyme 2, thus limiting the amount of angiotensin II available to the virus to cause damage. Clinical trials have confirmed that vitamin D supplementation reduces risk of acute respiratory tract infections, and approximately 30 observational studies have shown that incidence, severity, and death from COVID-19 are inversely correlated with serum 25(OH)D concentrations. Vitamin D supplementation is already familiar to many athletes and sports teams because it improves athletic performance and increases playing longevity. Thus, athletes should consider vitamin D supplementation to serve as an additional means by which to reduce risk of COVID-19 and its consequences.

Immunogenicity of a new allergoid from Felis domesticus

BACKGROUND

The chemical modification of allergens with glutaraldehyde improves safety while maintaining clinical efficacy, which permits the administration of higher doses of immunotherapy, reducing the risk of adverse reactions. The aim of this study is to evaluate the immunogenic capacity of a new cat dander polymer by immunizing mice and quantifying immunoglobulins in serum, in comparison with the non-modified allergen.

METHODS

The study consists of the immunization of three mice groups with the polymerized and the native extract, together with a negative control group. The immunoglobulin levels in serum have been measured by indirect ELISA. By means of the non-parametric Mann-Whitney U test, it was determined if there were significant differences in the values of specific antibodies between groups.

RESULTS

The group immunized with the allergoid showed significantly higher specific IgG and IgG1 values to dander allergens and specific IgG to the major allergen Fel d 1, while there were no significant changes in IgG2a and IgE values. These results could be due to a higher immunization dose. The vaccine formulation was based on the optimal defined dose for clinical efficacy of allergen immunotherapy.

CONCLUSIONS

This preclinical study carried out with the present assay has established that the allergoid of cat dander extract, as designed for its optimal use in allergen immunotherapy, produces a higher specific IgG than the native extract, in addition to showing significantly higher specific IgG1 levels, evidencing a greater effectiveness in immunization.

Mechanisms of allergen-specific immunotherapy and allergen tolerance

Allergen-specific immunotherapy (AIT) is the mainstay treatment for the cure of allergic disorders, with depicted efficacy and safety by several trials and meta-analysis. AIT impressively contributes to the management of allergic rhinitis, asthma and venom allergies. Food allergy is a new arena for AIT with promising results, especially via novel administration routes. Cell subsets with regulatory capacities are induced during AIT. IL-10 and transforming growth factor (TGF)-β are the main suppressor cytokines, in addition to surface molecules such as cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) within the micro milieu. Modified T- and B-cell responses and antibody isotypes, increased activity thresholds for eosinophils, basophils and mast cells and consequent limitation of inflammatory cascades altogether induce and maintain a state of sustained allergen-specific unresponsiveness. Established tolerance is reflected into the clinical perspectives as improvement of allergy symptoms together with reduced medication requirements and evolved disease severity. Long treatment durations, costs, reduced patient compliance and risk of severe, even life-threatening adverse reactions during treatment stand as major limiting factors for AIT. By development of purified non-allergenic, highly-immunogenic modified allergen extracts, and combinational usage of them with novel adjuvant molecules via new routes may shorten treatment durations and possibly reduce these drawbacks. AIT is the best model for custom-tailored therapy of allergic disorders. Better characterization of disease endotypes, definition of specific biomarkers for diagnosis and therapy follow-up, as well as precision medicine approaches may further contribute to success of AIT in management of allergic disorders.

Tolerance mechanisms in allergen immunotherapy

PURPOSE OF REVIEW

Allergen immunotherapy is the only treatment modality which alters the natural course of allergic diseases by restoring immune tolerance against allergens. Deeper understanding of tolerance mechanisms will lead to the development of new vaccines, which target immune responses and promote tolerance.

RECENT FINDINGS

Successful allergen immunotherapy (AIT) induces allergen-specific peripheral tolerance, characterized mainly by the generation of allergen-specific Treg cells and reduction of Th2 cells. At the early phase, AIT leads to a decrease in the activity and degranulation of mast cells and basophils and a decrease in inflammatory responses of eosinophils in inflamed tissues. Treg cells show their effects by secreting inhibitory cytokines including interleukin (IL)-10, transforming growth factor-β, interfering with cellular metabolisms, suppressing antigen presenting cells and innate lymphoid cells (ILCs) and by cytolysis. AIT induces the development of regulatory B cells producing IL-10 and B cells expressing allergen-specific IgG4. Recent investigations have demonstrated that AIT is also associated with the formation of ILC2reg and DCreg cells which contribute to tolerance induction.

SUMMARY

Research done so far, has shown that multiple molecular and cellular factors are dysregulated in allergic diseases and modified by AIT. Studies should now focus on finding the best target and ideal biomarkers to identify ideal candidates for AIT.

Efficacy of Granulocyte and Monocyte Adsorptive Apheresis in Patients With Inflammatory Bowel Disease Showing Lost Response to Infliximab

BACKGROUND AND AIMS

In inflammatory bowel disease [IBD] patients, antibody-to-infliximab [ATI] generation is responsible for loss of response [LOR] and infusion reaction [IR] to infliximab. An immuno-therapeutic approach is considered an option to overcome LOR. Granulocyte/monocyte adsorptive apheresis [GMA] using an Adacolumn has been shown to have clinical efficacy together with immunomodulatory effects in IBD patients.

METHODS

We developed an ATI-CAI assay utilizing a C1q immobilized plate and applied it to measure ATI in patients who were receiving infliximab, including 56 with sustained response, 76 with LOR and six with IR. Furthermore, 14 patients with LOR and two with paradoxical skin reactions who received infliximab + GMA combination therapy were analysed.

RESULTS

Fourteen patients with LOR, seven with Crohn's disease and seven with ulcerative colitis, showed significantly improved clinical indices [p = 0.0009], and decreased ATI [p = 0.0171] and interleukin-6 [p = 0.0537] levels at week 8 following initiation of infliximab + GMA therapy. Nine patients who received combination therapy achieved remission, which was maintained to week 24 with infliximab alone. Additionally, cutaneous lesions in two patients with IR were improved. ATI-CAI assay efficiency was not influenced by infliximab concentration during the test. Pre- and post-infliximab infusion ATI levels were not different. Patients with ATI greater than the 0.153 μg/mL cut-off value were likely to experience LOR [odds ratio 3.0].

CONCLUSIONS

Patients who received infliximab + GMA therapy appeared to regain clinical response to infliximab by a decrease in ATI level. Furthermore, the concentration of infliximab in the test did not influence ATI measurement, but was associated with clinical response.

Initiating pollen sensitization - complex source, complex mechanisms

The mechanisms involved in the induction of allergic sensitization by pollen are not fully understood. Within the last few decades, findings from epidemiological and experimental studies support the notion that allergic sensitization is not only dependent on the genetics of the host and environmental factors, but also on intrinsic features of the allergenic source itself. In this review, we summarize the current concepts and newest advances in research focusing on the initial mechanisms inducing pollen sensitization. Pollen allergens are embedded in a complex and heterogeneous matrix composed of a myriad of bioactive molecules that are co-delivered during the allergic sensitization. Surprisingly, several purified allergens were shown to lack inherent sensitizing potential. Thus, growing evidence supports an essential role of pollen-derived components co-delivered with the allergens in the initiation of allergic sensitization. The pollen matrix, which is composed by intrinsic molecules (e.g. proteins, metabolites, lipids, carbohydrates) and extrinsic compounds (e.g. viruses, particles from air pollutants, pollen-linked microbiome), provide a specific context for the allergen and has been proposed as a determinant of Th2 polarization. In addition, the involvement of various pattern recognition receptors (PRRs), secreted alarmins, innate immune cells, and the dependency of DCs in driving pollen-induced Th2 inflammatory processes suggest that allergic sensitization to pollen most likely results from particular combinations of pollen-specific signals rather than from a common determinant of allergenicity. The exact identification and characterization of such pollen-derived Th2-polarizing molecules should provide mechanistic insights into Th2 polarization and pave the way for novel preventive and therapeutic strategies against pollen allergies.

EAACI Allergen Immunotherapy User's Guide

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

Omega 3 Supplementation Can Regulate Inflammatory States in Gas Station Workers: A Double-Blind Placebo-Controlled Clinical Trial

Environmental exposure to diesel particulate matter and commercial gasoline in gas station workers might induce oxidative stress and changes in the balance of the immune system. In this study, the immunomodulatory impacts of omega 3 fatty acid (ω3FA) supplement were assessed on inflammatory and anti-inflammatory markers in gas station workers in a double-blind placebo-controlled clinical trial. Fifty-three men working in gas stations were treated with ω3FA (n = 29) or placebo (n = 24) for 60 days. C-reactive protein, interleukin-12 (IL-12), transforming growth factor β (TGF-β), interferon γ (IFN-γ), tumor necrosis factor α, IL-10, and IL-17 levels were measured by enzyme-linked immunosorbent assay method before and after the completion of the trial. The concentrations of IFN-γ and IL-17 were significantly decreased in ω3FA group compared with the placebo group (P < 0.001). Moreover, the levels of inhibitory cytokines including TGF-β and IL-10 significantly were increased in ω3FA group (P < 0.001). Overall, ω3FA nutritional supplementation can be useful in reducing inflammatory immune responses and maintaining immune tolerance in people with high exposure to inflammation-inducing factors. [Figure: see text].

[Development of an Immune Regulation Technology Targeting the Skin and Promotion of the Practical Applications of Transcutaneous Vaccination/Immunotherapy]

In the premise of vaccination and allergen-specific immunotherapy, transcutaneous formulations have an advantage over conventional subcutaneous injections in terms of convenience, simplicity of delivery, and painless administration into the skin. Additionally, since transcutaneous formulations can be rendered cold-chain free, they do not require expert handling during transportation, storage, and stockpiling, which enables reductions in costs and distribution to distant areas. Furthermore, transcutaneous formulations are effective for improving adherence in children with phobias toward injection needles and may help in persuading them to perform self-vaccination and home immunotherapy against allergies in the future. We have been promoting the development of innovative "patch-type formulations for vaccination and immunotherapy" which regard skin as an immune organ and utilize our original transcutaneous administration devices (hydrophilic gel patch and microneedle patch) for their delivery. We have confirmed the safety and efficacy of transcutaneous formulations not only in demonstration experiments using animals but also in physician-initiated clinical studies. Additionally, in order to elucidate the mechanism for the induction of immune responses by transcutaneous formulations, we analyzed the immunological events occurring in the skin and regional lymph nodes which accompanied the application of transcutaneous administration devices or the delivery of antigens (vaccines and allergens) to the skin surface layer. This review presents our results from basic to clinical research on the development of transcutaneous formulations for vaccines and allergen-specific immunotherapy.

Therapeutic potential of peptides from Ole e 1 in olive-pollen allergy

Olive-pollen allergy is one of the leading causes of respiratory allergy in Mediterranean countries and some areas of North America. Currently, allergen-specific immunotherapy is the only etiophatogenic treatment. However, this approach is not fully optimal, safe, or effective. Thus, efforts continue in the search for novel immunotherapy strategies, being one of the most promising the use of peptides derived from major allergens. This work tries to determine the therapeutic potential and safety of 5 dodecapeptides derived from the main allergen of olive-pollen allergy, Ole e 1. The immunomodulatory capacity of these peptides was studied using peripheral blood mononuclear cells (PBMCs) obtained from 19 olive-pollen-allergic patients and 10 healthy controls. We determined the capacity of these peptides to inhibit the proliferative response toward olive-pollen allergenic extract and to induce the regulatory cytokines, IL-10 and IL-35. To test the safety and absence of allergenicity of the peptides, the basophil activation was analyzed by flow-cytometry, using peripheral blood. The results showed that two of five peptides inhibited near to 30% the proliferative response against the total olive-pollen allergenic extract in olive-pollen-allergic patients. Inhibition increased to nearly 35% when the 5 peptides were used in combination. In both cases, a statistically significant induction of IL-10 and IL-35 secretion was observed in the supernatants of allergic patients PBMCs cultures. None of the 5 peptides induced basophil activation and cross-link inflammatory cell-bound IgE. In conclusion, these results open up new possibilities in the treatment of olive-pollen allergy, which could solve some of the problems facing current therapy approaches.

The blockade of PD-1/PD-L1 pathway promotes the apoptosis of CD19+ CD25+ Bregs and suppresses the secretion of IL-10 in patients with allergic rhinitis

PD-1/PD-L1 pathway is crucial to immune regulation by controlling the balance between T cell tolerance and activation. However, the association between PD-1/PD-L1 pathway and regulatory B cells has not been fully investigated in allergic rhinitis. In this study, we detected the number of peripheral CD19⁺ CD25⁺ Bregs and the expression of IL-10 on this cell subset in healthy control and patients with allergic rhinitis using flow cytometry. Then, we evaluated the level of PD-L1 in CD19⁺ CD25⁺ Bregs and investigated the correlation between PD-L1 and CD4⁺ follicular T helper cells. Finally, we studied the effects of anti-PD-L1 on the apoptosis of Bregs and the production of IL-10. Comparing with healthy controls, the percentage of CD19⁺ CD25⁺ Bregs and the expression of IL-10 were both significantly decreased in AR group. In addition, the expression of PD-L1 on CD19⁺ CD25⁺ Bregs was also lower in allergic rhinitis patients. Interestingly, a negative correlation was found between the expression of PD-L1⁺ Bregs and CD4⁺ CXCR5⁺ follicular T helper cells. In vitro assay revealed that anti-PD-L1 promoted Bregs apoptosis and inhibited the expression of IL-10 in CD19⁺ CD25⁺ Bregs. Collectively, these results suggest that PD-L1 expressed on CD19⁺ CD25⁺ Bregs may be a potential regulator in the treatment of allergic rhinitis. Blockade of PD-1/PD-L1 pathway might be a valuable pathogenic target for allergic rhinitis through inhibiting the secretion of immunosuppressive cytokine and promoting CD19⁺ CD25⁺ Bregs apoptosis.

The regulatory B cell-mediated peripheral tolerance maintained by mast cell IL-5 suppresses oxazolone-induced contact hypersensitivity

The function of regulatory immune cells in peripheral tissues is crucial to the onset and severity of various diseases. Interleukin-10 (IL-10)-producing regulatory B (IL-10⁺ B_reg) cells are known to suppress various inflammatory diseases. However, evidence for the mechanism by which IL-10⁺ B_reg cells are generated and maintained is still very limited. Here, we found that IL-10⁺ B_reg cells suppress the activation of IL-13-producing type 2 innate lymphoid cells (IL-13⁺ ILC2s) in an IL-10-dependent manner in mice with oxazolone-induced severe contact hypersensitivity (CHS). Mast cell (MC) IL-5 was important for maintaining the population of IL-10⁺ B_reg cells in peripheral lymphoid tissues. Overall, these results uncover a previously unknown mechanism of MCs as a type of immunoregulatory cell and elucidate the cross-talk among MCs, IL-10⁺ B_reg cells, and IL-13⁺ ILC2s in CHS.

Immune Tolerance Therapy: A New Method for Treatment of Traumatic Brain Injury

Objective:

Due to the special anatomical structure and pathophysiological mechanism of the central nervous system (CNS), there is a big difference between the repair of brain injury and other systems of the body. More and more evidence shows that targetedly reducing the autoimmune response of brain tissue without affecting the immune function in other parts of the body will be the best optimized treatment for brain injury.

Data Sources:

This review was based on data in articles published in PubMed up to June 5, 2017, with the following keywords: “immune tolerance”, “traumatic brain injury”, and “central nervous system”.

Study Selection:

Original articles and critical reviews on immune tolerance and brain damage were selected for this review. References of the retrieved articles were also screened to search for potentially relevant papers.

Results:

The CNS is isolated from the immune system through the blood-brain barrier. After brain injury, brain antigens are released into the systemic circulation to induce damaging immune responses. Immune tolerance can effectively reduce the brain edema and neurological inflammatory response after brain injury, which is beneficial to the recovery of neurological function. The clinical application prospect and theoretical research value of the treatment of immune tolerance on traumatic brain injury (TBI) is worth attention.

Conclusions:

The establishment of immune tolerance mechanism has a high clinical value in the treatment of TBI. It opens up new opportunities for the treatment of brain damage.

IL-10 Receptor or TGF-β Neutralization Abrogates the Protective Effect of a Specific Nondigestible Oligosaccharide Mixture in Cow-Milk-Allergic Mice

Background

Dietary nondigestible, short-chain galacto-, long-chain fructo-, and pectin-derived acidic oligosaccharides (GFAs) lower the effector response in cow-milk-allergic (CMA) mice; and forkhead box P3 (Foxp3)-positive regulatory T cells (Tregs) were shown to contribute to this.

Objective

The aim of this study was to assess the contribution of interleukin 10 (IL-10) and transforming growth factor β (TGF-β) to the protective effect of the GFA diet in CMA mice.

Methods

Female C3H/HeOuJ mice, 3-4 wk old, were orally sensitized with cholera toxin (Sham) or whey and cholera toxin (Whey) 1 time/wk for 5 consecutive weeks and challenged with whey 1 wk later. The mice were fed a control or 1% GFA (9:2:1) (Whey+GFA) diet starting 2 wk before the first sensitization. In a second experiment, the mice were also injected with αIL-10 receptor (αIL-10r), αTGF-β, or isotype control antibodies 24 h before each sensitization. The acute allergic skin response, anaphylaxis score, whey-specific IgE, mucosal mast cell protease 1 (mMCP-1), and Treg frequency in the mesenteric lymph nodes (MLNs) and intestinal Foxp3, Il10, and Tgfb mRNA expression were determined.

Results

In Whey+GFA mice, intestinal Il10, Tgfb, or Foxp3 mRNA expression was 2-10 times higher (P < 0.05) and the MLN Treg frequency was 25% higher compared with Whey mice (P < 0.05). The acute allergic skin response was 50% lower in Whey+GFA mice compared with Whey mice (P < 0.01), and IL-10 receptor (IL-10r) or TGF-β neutralizing antibodies prevented this protective effect (P < 0.001). The Whey mice had higher serum mMCP-1 concentrations and whey-immunoglobulin E (-IgE) levels than Sham mice (P < 0.01), whereas these were not higher in Whey+GFA mice, and neutralizing antibodies partially interfered with these responses.

Conclusions

Dietary GFAs enhance the Treg frequency in the MLNs and mucosal IL-10 and TGF-β transcription while suppressing the allergic effector response. Neutralizing antibodies showed that the allergy-protective effect of the GFA diet was mediated by IL-10 and TGF-β in CMA mice.

Immunological Mechanisms in Allergic Diseases and Allergen Tolerance: The Role of Treg Cells

The immune system regulates itself to establish an appropriate immune response to potentially harmful pathogens while tolerating harmless environmental antigens and self-antigens. A central role in this balance is played by regulatory T cells (Tregs) through various ways of actions. By means of molecule secretion and cell-cell contact mechanisms, Tregs may have the capacity to modulate effector T cells and suppress the action of proinflammatory cytokines across a broad range of cell types. As a result, abnormal regulatory T cell function has been pointed as a main cause in the development of allergic diseases, a major public health problem in industrialized countries, with a high socioeconomic impact. This prevalence and impact have created an international interest in improving the allergy diagnosis and therapy. Additionally, research has sought to gain a better understanding of the molecular mechanisms underlining this kind of disease, in order to a better management. At this respect, the role of Treg cells is one of the most promising areas of research, mainly because of their potential use as new immunotherapeutical approaches. Therefore, the aim of this review is to update the existing knowledge of the role of Tregs in this pathology deepening in their implication in allergen-specific therapy (AIT).

Dietary Intervention with β-Lactoglobulin-Derived Peptides and a Specific Mixture of Fructo-Oligosaccharides and Bifidobacterium breve M-16V Facilitates the Prevention of Whey-Induced Allergy in Mice by Supporting a Tolerance-Prone Immune Environment

Cow's milk allergy (CMA) prevails in infants and brings increased risk of developing other allergic diseases. Oral administration of specific β-lactoglobulin (BLG)-derived peptides (PepMix) and a specific blend of short- and long-chain fructo-oligosaccharides and Bifidobacterium breve M-16V (FF/Bb) was found to partially prevent CMA development in mice. In this study, we aimed to expand the knowledge on the preventive potential and the underlying mechanisms of this approach. Three-week-old female C3H/HeOuJ mice were orally exposed to PepMix±FF/Bb prior to a 5-week oral sensitization with whole whey and cholera toxin as an adjuvant. The acute allergic skin response was determined after an intradermal challenge with whole whey protein. Following an oral challenge with whey, regulatory T cells (T_regs) in the small intestine lamina propria (SI-LP) and mRNA expression of immune markers in the Peyer's patches (PP) were investigated. The early impact of PepMix and FF/Bb interventions on the immune system during the oral tolerance (OT) induction phase was investigated after the last OT administration. Pre-exposing mice to PepMix+FF/Bb partially prevented the acute allergic skin response compared to PBS and increased T_regs and activated T cells in the SI-LP compared to sham-sensitized mice. It also increased the mRNA expression of Tbet over GATA3 in the PP of whey-sensitized mice. Directly upon the 6-day OT phase, FF/Bb intervention enhanced cecal content levels of propionic and butyric acid in PepMix-fed mice and the former was positively correlated with Foxp3⁺ cell numbers in the colon. In the PP of PepMix+FF/Bb-exposed mice, IL-22 mRNA expression increased and IL-10 followed the same tendency, while the Foxp3 expression was increased over GATA3 and RorγT. In the colon, the Tbet mRNA expression increased over GATA3, while IL-22 decreased. In addition, the Foxp3⁺/GATA3⁺ and regulatory/effector T cell ratios in the mesenteric lymph nodes and the CD11b⁺/CD11b^- conventional dendritic cells ratio in the SI-LP were increased. In conclusion, the FF/Bb diet facilitates the capacity of the specific BLG-peptides to partially prevent the allergic response after sensitization to whole whey protein, possibly by creating a tolerance-prone environment during the OT phase. Such a dietary intervention might contribute to tailoring successful strategies for CMA prevention.

Murine models for mucosal tolerance in allergy

Immunity is established by a fine balance to discriminate between self and non-self. In addition, mucosal surfaces have the unique ability to establish and maintain a state of tolerance also against non-self constituents such as those represented by the large numbers of commensals populating mucosal surfaces and food-derived or air-borne antigens. Recent years have seen a dramatic expansion in our understanding of the basic mechanisms and the involved cellular and molecular players orchestrating mucosal tolerance. As a direct outgrowth, promising prophylactic and therapeutic models for mucosal tolerance induction against usually innocuous antigens (derived from food and aeroallergen sources) have been developed. A major theme in the past years was the introduction of improved formulations and novel adjuvants into such allergy vaccines. This review article describes basic mechanisms of mucosal tolerance induction and contrasts the peculiarities but also the interdependence of the gut and respiratory tract associated lymphoid tissues in that context. Particular emphasis is put on delineating the current prophylactic and therapeutic strategies to study and improve mucosal tolerance induction in allergy.

Deciphering the black box of food allergy mechanisms

OBJECTIVE

To review our current understanding of immunotherapy, the immune mechanisms underlying food allergy, and the methodological advances that are furthering our understanding of the role of immune cells and other molecules in mediating food allergies.

DATA SOURCES

Literature searches were performed using the following combination of terms: allergy, immunotherapy, food, and mechanisms. Data from randomized clinical studies using state-of-the-art mechanistic tools were prioritized.

STUDY SELECTIONS

Articles were selected based on their relevance to food allergy.

RESULTS

Current standard of care for food allergies is avoidance of allergenic foods and the use of epinephrine in case of severe reaction during unintentional ingestion. During the last few decades, great strides have been made in understanding the cellular and molecular mechanisms underlying food allergy, and this information is spearheading the development of exciting new treatments.

CONCLUSION

Immunotherapy protocols are effective in desensitizing individuals to specific allergens; however, recurrence of allergic sensitization is common after discontinuation of therapy. Interestingly, in a subset of individuals, immunotherapy is protective against allergens even after discontinuation of immunotherapy. Whether this protection is permanent is currently unknown because of inadequate long-term follow-up data. Research on understanding the underlying mechanisms may assist in modifying protocols to improve outcome and enable sustained unresponsiveness, rather than a temporary relief against food allergies. The cellular changes brought about by immunotherapy are still a black box, but major strides in our understanding are being made at an exciting pace.

Differences and similarities between sublingual immunotherapy of allergy and oral tolerance

Allergen immunotherapy is the only treatment altering the natural course of IgE-mediated allergies. Whereas the subcutaneous route for immunotherapy (SCIT) has been historically considered as a reference, we discuss herein the relative advantages of the sublingual and oral routes as alternatives to SCIT in order to elicit allergen-specific tolerance. The buccal and gut immune systems are similarly organized to favor immune tolerance to antigens/allergens, due to the presence of tolerogenic dendritic cells and macrophages promoting the differentiation of CD4⁺ regulatory T cells. Sublingual immunotherapy (SLIT) is now established as a valid treatment option, with clinical efficacy demonstrated in allergic rhinoconjunctivitis (to either grass, tree, weed pollens or mite allergens) and encouraging results obtained in the management of mild/moderate allergic asthma. While still exploratory, oral immunotherapy (OIT) has shown promising results in the desensitization of patients with food allergies. We review at both biological and clinical levels the perspectives currently pursued for those two mucosal routes.

Randomized controlled trial of oral immunotherapy for egg allergy in Japanese patients

BACKGROUND

Egg allergy is one of the most common food allergies in young children. While oral immunotherapy (OIT) is not routinely recommended in current guidelines, it has been considered as a potential alternative treatment strategy. Studies on OIT for food allergy have been explored, but no controlled trials have been reported in Japan.

METHODS

The first oral food challenge (OFC) was performed before treatment to ensure diagnosis and evaluate the threshold dose for egg using the double-blind, placebo-controlled food challenge. Participants were randomly assigned by computerized algorithm to receive OIT using egg (OIT group) or no egg (egg elimination [EE] group). A second OFC was performed in both groups approximately 6 months after therapy. Blood samples were collected and egg white-specific immunoglobulin (Ig)E and IgG4 were measured before and after the treatment period.

RESULTS

Eight of the 14 patients (57%) in the OIT group had no allergic reaction to 4 g dry egg powder whereas none of the 16 patients in the EE group did. All 14 patients in the OIT group had increased threshold for egg powder in the second OFC compared with baseline. There was no significant change in egg white-specific IgE level during therapy. After therapy, egg white-specific IgG4 increased significantly in the OIT group, but not in the EE group.

CONCLUSION

OIT is effective in increasing the threshold for allergens and inducing desensitization in Japanese egg allergy patients, similarly to North American and European patients.

The relationship of serum vitamins A, D, E and LL-37 levels with allergic status, tonsillar virus detection and immune response

Background

Tonsils have an active role in immune defence and inducing and maintaining tolerance to allergens. Vitamins A, D, and E, and antimicrobial peptide LL-37 may have immunomodulatory effects. We studied how their serum levels were associated with allergy status, intratonsillar/nasopharyngeal virus detection and intratonsillar expression of T cell- and innate immune response-specific cytokines, transcription factors and type I/II/III interferons in patients undergoing tonsillectomy.

Methods

110 elective tonsillectomy patients participated. Serum levels of vitamins A, 25(OH)D, and E, LL-37 and allergen-specific IgE as well as nasopharyngeal/intratonsillar respiratory viruses were analyzed. The mRNA expression of IFN-α, IFN-β, IFN-γ, IL-10, IL-13, IL-17, IL-28, IL-29, IL-37, TGF-β, FOXP3, GATA3, RORC2 and Tbet in tonsils were analyzed by quantitative RT-PCR.

Results

The median age of the patients was 16 years (range 3–60), 28% of subjects had atopy, and 57% carried ≥1 respiratory virus in nasopharynx. Detection of viruses decreased by age. Higher vitamin A levels showed borderline significance with less viral detection (P = 0.056). Higher 25(OH)D was associated with less allergic rhinitis and atopy (P < 0.05) and higher vitamin E with less self-reported allergy (P < 0.05). In gene expression analyses, 25(OH)D was associated with higher IL-37, vitamin A with higher IFN-γ and vitamin E with less IL-28 (P < 0.05). LL-37 was associated with less FOXP3, RORC2 and IL-17 in tonsils (P < 0.05).

Conclusions

Vitamin D and E levels were associated with less allergic disorders. Vitamin A was linked to antiviral and vitamin D with anti-inflammatory activity. LL-37 and was linked to T regulatory cell effects.

Immune Regulation by Ubiquitin Tagging as Checkpoint Code

The immune system is equipped with effective machinery to mobilize its activation to defend invading microorganisms, and at the same time, to refrain from attacking its own tissues to maintain immune tolerance. The balance of activation and tolerance is tightly controlled by diverse mechanisms, since breakdown of tolerance could result in disastrous consequences such as the development of autoimmune diseases. One of the mechanisms is by the means of protein ubiquitination, which involves the process of tagging a small peptide ubiquitin to protein substrates. E3 ubiquitin ligases are responsible for catalyzing the final step of ubiquitin-substrate conjugation by specifically recognizing substrates to determine their fates of degradation or functional modification. The ubiquitination process is reversible, which is carried out by deubiquitinating enzymes to release the ubiquitin molecule from the conjugated substrates. Protein ubiquitination and deubiquitination serve as checkpoint codes in many key steps of lymphocyte regulation including the development, activation, differentiation, and tolerance induction. In this chapter, we will discuss a few E3 ligases and deubiquitinating enzymes that are important in controlling immune responses, with emphasis on their roles in T cells.

Polyspecificity of Anti-lipid A Antibodies and Its Relevance to the Development of Autoimmunity

The process of natural selection favours germ-line gene segments that encode CDRs that have the ability to recognize a range of structurally related antigens. This presents an immunological advantage to the host, as it can confer protection against a common pathogen and still cope with new or changing antigens. Cross-reactive and polyspecific antibodies also play a central role in autoimmune responses, and a link has been shown to exist between auto-reactive B cells and certain bacterial infections. Bacterial DNA, lipids, and carbohydrates have been implicated in the progression of autoimmune diseases such as systemic lupus erythematosus. As well, reports of anti-lipid A antibody polyspecificity towards single-stranded DNA together with the observed sequence homology amongst isolated auto- and anti-lipid A antibodies has prompted further study of this phenomenon. Though the lipid A epitope appears cryptic during Gram-negative bacterial infection, there have been several reported instances of lipid A-specific antibodies isolated from human sera, some of which have exhibited polyspecificity for single stranded DNA. In such cases, the breakdown of negative selection through polyspecificity can have the unfortunate consequence of autoimmune disease. This review summarizes current knowledge regarding such antibodies and emphasizes the features of S1-15, A6, and S55-5, anti-lipid A antibodies whose structures were recently determined by X-ray crystallography.

Immunoproteomic analysis of house dust mite antigens reveals distinct classes of dominant T cell antigens according to function and serological reactivity

BACKGROUND

House dust mite (HDM) allergens are a common cause of allergy and allergic asthma. A comprehensive analysis of proteins targeted by T cells, which are implicated in the development and regulation of allergic disease independent of their antibody reactivity, is still lacking.

OBJECTIVE

To comprehensively analyse the HDM-derived protein targets of T cell responses in HDM-allergic individuals, and investigate their correlation with IgE/IgG responses and protein function.

METHODS

Proteomic analysis (liquid chromatography-tandem mass spectrometry) of HDM extracts identified 90 distinct protein clusters, corresponding to 29 known allergens and 61 novel proteins. Peripheral blood mononuclear cells (PBMC) from 20 HDM-allergic individuals were stimulated with HDM extracts and assayed with a set of ~2500 peptides derived from these 90 protein clusters and predicted to bind the most common HLA class II types. 2D immunoblots were made in parallel to elucidate IgE and IgG reactivity, and putative function analyses were performed in silico according to Gene Ontology annotations.

RESULTS

Analysis of T cell reactivity revealed a large number of T cell epitopes. Overall response magnitude and frequency was comparable for known and novel proteins, with 15 antigens (nine of which were novel) dominating the total T cell response. Most of the known allergens that were dominant at the T cell level were also IgE reactive, as expected, while few novel dominant T cell antigens were IgE reactive. Among known allergens, hydrolase activity and detectable IgE/IgG reactivity are strongly correlated, while no protein function correlates with immunogenicity of novel proteins. A total of 106 epitopes accounted for half of the total T cell response, underlining the heterogeneity of T cell responses to HDM allergens.

CONCLUSIONS AND CLINICAL RELEVANCE

Herein, we define the T cell targets for both known allergens and novel proteins, which may inform future diagnostics and immunotherapeutics for allergy to HDM.

Markers of tolerance development to food allergens

IgE-mediated reactions to food allergens are the most common cause of anaphylaxis in childhood. Although allergies to cow's milk, egg, or soy proteins, in contrast to peanut and tree nut allergens, resolve within the first 6 years of life in up to 60% due to natural tolerance development, this process is not well understood. At present, there is no cure or treatment for food allergy that would result in an induction of tolerance to the symptom-eliciting food. Avoidance, providing an emergency plan and education, is the standard of treatment. Oral immunotherapeutic approaches have been proven reasonable efficacy; however, they are associated with high rates of side-effects and low numbers of patients achieving tolerance. Nevertheless, mechanisms that take place during oral immunotherapy may help to understand tolerance development. On the basis of these therapeutic interventions, events like loss of basophil activation and induction of regulatory lymphocyte subsets and of blocking antibodies have been described. Their functional importance at a clinical level, however, remains to be investigated in detail. Consequently, there is eminent need to understand the process of tolerance development to food allergens and define biomarkers to develop and monitor new treatment strategies for food allergy.

Mechanisms of Aeroallergen Immunotherapy: Subcutaneous Immunotherapy and Sublingual Immunotherapy

Allergen immunotherapy (AIT) is an effective way to treat allergic disorders, targeting the underlying mechanisms and altering the disease course by inducing a long-lasting clinical and immune tolerance to allergens. Although sublingual and subcutaneous routes are used in daily practice, many novel ways to decrease side effects and duration and increase efficacy have been pursued. Further studies are needed to develop biomarkers for the identification of AIT responder patients and also to use the developed knowledge in allergy prevention studies. Future directions in AIT include treatments for autoimmune diseases, chronic infections, organ transplantation, and breaking immune tolerance to cancer cells.

Immunologic alterations and efficacy of subcutaneous immunotherapy with Dermatophagoides pteronyssinus in monosensitized and polysensitized patients

BACKGROUND

There is a continuing debate about whether monoallergen subcutaneous immunotherapy (SCIT) is able to modulate immune and clinical responses toward main causal allergen in polysensitized patients.

OBJECTIVE

To investigate short-term immunologic changes and clinical effectiveness of SCIT with Dermatophagoides pteronyssinus in monosensitized and polysensitized patients who have rhinitis with or without asthma.

METHODS

Nineteen monosensitized and 24 polysensitized patients participated in this prospective, self-placebo-controlled, interventional study. Cluster immunotherapy with D pteronyssinus was administered after 2 months of placebo in both groups. Immunologic parameters, including CD203c expression on basophils after allergen stimulation, total IgE, specific IgE, and specific IgG4, were evaluated at baseline, after placebo, and after immunotherapy. Clinical effectiveness was assessed using monthly symptom-medication scores, visual analog scale, quality-of-life questionnaire, and nasal allergen provocation test.

RESULTS

At baseline, polysensitized patients had higher CD203c expression on basophils than monosensitized patients (P = .007). Activated basophils expressing CD203c, total IgE, and specific IgG4 were significantly increased after immunotherapy compared with baseline and placebo in the polysensitized group (P < .025). After immunotherapy, specific IgE and D pteronyssinus-induced CD203c expression were significantly higher in polysensitized than monosensitized patients (P < .05). The total symptom scores and the Mini Rhinoconjunctivitis Quality of Life Questionnaire scores in polysensitized patients and the visual analog scale scores in both groups were lower after immunotherapy compared with baseline and placebo (P < .025). Titrated nasal allergen provocation test with D pteronyssinus increased after immunotherapy in the monosensitized group (P < .05).

CONCLUSION

This study indicates that monosensitized and polysensitized patients have distinct humoral response and basophil behavior to SCIT. However, a single-allergen immunotherapy corresponding to the most clinically troublesome allergy in polysensitized patients can lead to early clinical efficacy comparable to that seen in monosensitized patients.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01795846.

Initial immunological changes as predictors for house dust mite immunotherapy response

BACKGROUND

Although specific immunotherapy is the only aetiological treatment for allergic disorders, the underlying mechanisms are not fully understood. Specific immunotherapy induces changes in lymphocyte Th subsets from Th2 to Th1/Treg. Whether differences in immunological patterns underlie patient response to immunotherapy has not yet been established.

OBJECTIVES

We studied the immunological changes occurring during a 1-year period of Dermatophagoides pteronyssinus (DP) immunotherapy and their relation with clinical outcome.

METHODS

We included 34 patients with DP allergy who received subcutaneous specific immunotherapy (SCIT) for 1 year. Following treatment, patients were classified as responders or non-responders. Fourteen allergic subjects who did not receive SCIT were included as controls. Peripheral blood was obtained at 0, 1, 3, 6 and 12 months and cultured with nDer p 1. Phenotypic changes, cytokine production and basophil response were analysed by flow cytometry; transcription factors were measured by mRNA quantification. Serum immunoglobulin levels were also measured.

RESULTS

After 1 year of SCIT, 82% of cases showed improved symptoms (responders). Although increases in sIgG4 were observed, BAT reactivity was not modified in these patients. Increases in T-BET/FOXP3 as well as nDer p 1-specific Th1/Treg frequencies were also observed, along with a decrease in Th2, Th9 and Th17. These changes corresponded to changes in cytokine levels.

CONCLUSION

Patients who respond well to DP-SCIT show immunological differences compared to non-responders. In responders, basal differences include a lower frequency of Th1 and higher frequencies of Th2, Th9 and Th17 cells. After 1 year of treatment, an increased production of sIgG4 was observed in responders, along with a change in Th2 response towards Th1/Treg.

MARKERS OF ATOPIC REACTIVITY IN THE PUPILS WITH SEVERE BRONCHIAL ASTHMA

The aim of the work was to increase the effectiveness of treatment of the severe asthma phenotype in school-age children, taking into account the diagnostic value of atopic reactivity indicators. The study involved 30 pupils with severe asthma and 30 children with moderate-heavy version of it. Amid severe asthma increases risk of higher concentrations of IL-4 and IL-5 in the serum, and almost in every second child was observed the increased concentrations of Ig E (more than 545,3 IU/mL, odds ratio was 1,9 (95 % CI 1,1-3,4). In the group of patients with severe asthma were significantly more frequent cases of the skin hypersensitivity to household allergens with respect to the members of the second group. There were separated the indices of clinical and epidemiological risk and diagnostic value of some markers of atopic reactivity for verification of the severe asthma phenotype. It was established that the development of severe asthma in children marked tendency to reduce the metabolic activity of eosinophilic granulocytes in blood (in terms of intracellular content of cationic proteins and peroxidase) and phagocytic ability of these effector cells of allergic inflammation. For the phenotype of severe asthma the risk of high concentration of IL-4 and IL-5 in serum increased in 3,1 times, but this paraclinical test is rather suitable for verification of this phenotype (SP – 84,6% (95 % Sp 75,9–91,1)) than for its detection (Se – 36,4 % (95 % CI 26,9–46,6)).