Immunoglobulin E-Mediated Autoimmunity

Comparative efficacy and safety of the treatment by Omalizumab for chronic idiopathic urticaria in the general population: A systematic review and network meta-analysis

BACKGROUND

Omalizumab is the only licensed drug that serves as a third-line treatment for chronic idiopathic urticaria (CIU). The optimum doses of omalizumab remain controversial. Therefore, this study aims to estimate the efficacy and safety of different doses of omalizumab in the treatment of CIU patients.

MATERIALS AND METHODS

Four databases were searched from the database's creation to April 8, 2023. Several keywords such as omalizumab and urticarias were used to retrieve related studies. The meta-analytical outcomes were analyzed in R 4.2.1 software and Stata 15.1 software. Cochrane risk-of-bias tool Ver. 2 was used to evaluate the risk of bias in randomized controlled trials (RCTs).

RESULTS

In total, 2331 patients were included. Five indexes were employed to assess, including weekly Itch Severity Score (ISS7), weekly Hive Severity Score (HSS7), weekly Urticaria Activity Score (UAS7), Dermatology Life Quality Index (DLQI), and adverse events (AE). A 300 mg dose of omalizumab was the optimum dose to treat CIU, followed by the 150 mg dose. Furthermore, 600 mg of omalizumab only showed a significant difference from the placebo in HSS7. No significant statistical difference was observed in AE. Meta-regression analysis revealed that time, as a covariate, was statistically significant in the comparison of omalizumab 150 mg with placebo.

CONCLUSION

300 mg of omalizumab was the optimum dosage to treat CIU patients, with a 150 mg dose also exhibiting good efficacy. Further studies are required to explore the efficacy and safety of different doses of omalizumab in the treatment of CIU patients.

Dietary Galacto-oligosaccharides Ameliorate Atopic Dermatitis-like Skin Inflammation and Behavioral Deficits by Modulating Gut Microbiota-Brain-Skin Axis

Atopic dermatitis (AD), a chronic, highly pruritic, and inflammatory skin disorder, often coexists with psychiatric comorbidities including anxiety and depression, posing considerable challenges for treatment. The current research aims at evaluating the efficacy and potential therapeutic mechanism of galacto-oligosaccharides (GOS) on AD-like skin lesions and comorbid anxiety/depressive disorders. Macroscopical and histopathological examination showed that GOS could markedly relieve skin inflammation by decreasing the production of IgE, IL-4, IL-13, IFN-γ, and TNF-α and regulating the PPAR-γ/NF-κB signaling in DNFB-induced AD mice. Moreover, GOS significantly improved the anxiety- and depressive-like symptoms as mirrored by the behavior tests including FST, TST, OFT, and EZM through normalizing the neurotransmitter levels of 5-HT, DA, NE, and CORT in the brain. Mechanistically, by virtue of the high-throughput 16S rRNA gene sequencing and GC-MS techniques, GOS restructured the gut microbiota and specifically induced the proliferation of Lactobacillus and Alloprevotella, leading to an increase in the total content of fecal SCFAs, in particular acetate and butyrate. Pearson correlation analysis found a marked correlation among the altered gut microbiota/SCFAs, AD-associated skin manifestations, and comorbid behavioral phenotypes. Collectively, this work highlights that GOS is a promising strategy against both AD and associated depressive symptoms by modulating the gut microbiota-brain-skin axis.

Unveiling the Allergy-Meniere Connection: Exploring the Impact of Allergen Positivity on Meniere's Disease Severity

Meniere's Disease is a rare ear disorder that can cause severe morbidity to the patient and has no definitive treatment to date. Endolymphatic hydrops is the critical event. Though symptomatology is well understood, the exact etiology of Endolymphatic hydrops attack is still unclear. Twenty-five consecutive patients of Meniere's Disease diagnosed in the Vertigo clinic aged 12 to 70 years were included. Their allergic status was evaluated using a skin prick test. Allergic and non-allergic patients were then identified. Comparison between the two groups was made to identify the effect of allergy on the severity of symptoms using vertigo scales, Functional level scale, Dizziness handicap index, and Pure tone average staging. The prevalence of allergy among Meniere's Disease patients was 56%. The most common allergen found in our study was tyrophagus(n = 8). Polysensitization was more common(n = 12). Airborne allergens were more common than food allergens. There was no significant relationship between the severity scales and the allergen positivity status (p > 0.05). The prevalence of allergy is more among patients with Meniere's Disease. The Endolymphatic sac is allergy prone. The occurrence of endolymphatic hydrops may be due to a cross-reaction of allergen-induced IgE antibodies to self-antigen. Management of the specific allergen may help decrease symptomatology in these patients. Allergen-specific therapies have a promising role in the treatment of allergic conditions and provide a long-term symptom-free period in affected individuals. This can be applied in patients with Meniere's Disease having associated allergic features based on their skin prick test results.

The role of Aedes aegypti in inducing/aggravating IgE-mediated allergic airway disease: extensive computational studies for identification of allergenic proteins

Respiratory allergies have become a major public health concern and affect one-third of the world's population. Several factors like environmental changes, industrialization, and immunologic interactions are reported to contribute to allergic respiratory diseases. Immunological reactions because of mosquito bite (allergic proteins) have been reported to have a high contribution to IgE-mediated allergic airway disease but they are largely ignored. In this study, we aim to predict the potential allergens (proteins) from Aedes aegypti that might play a role in the reactions of IgE-mediated allergic airway diseases. The allergens are identified from an extensive literature search and the 3D structures were prepared using the SwissDock server. Computational studies were performed to identify the potential allergens that might be responsible for IgE-mediated allergies. Our docking and molecular dynamics (MD) simulation results suggest that ADE-3, an allergen from Aedes aegypti, has the highest docking score and is predicted to be responsible for IgE-mediated allergic reaction(s). Overall, this study highlights the importance of immunoinformatics, and the obtained information can be used for designing prophylactic peptide vaccine candidates and inhibitors for controlling IgE-mediated inflammations.Communicated by Ramaswamy H. Sarma.

Comorbid Inducible Urticaria Is Linked to Non-Autoimmune Chronic Spontaneous Urticaria: CURE Insights

BACKGROUND

Patients with chronic spontaneous urticaria (CSU) can have comorbid inducible urticaria (CIndU). How comorbid CIndU affects patients and their CSU is largely unclear.

OBJECTIVE

To compare patients with CSU with and without comorbid CIndUs for differences in demographic features, clinical characteristics, and laboratory markers.

METHODS

We analyzed 708 patients with CSU of our Urticaria Center of Reference and Excellence enrolled in CURE, the chronic urticaria registry. CURE data collected until October 2022 were used to compare patients with and without comorbid CIndU for their demographic characteristics, disease onset, activity, impact, and control, as well as concomitant allergic and autoimmune diseases and laboratory parameters associated with autoimmune CSU.

RESULTS

Of 708 patients with CSU, 247 (35%) had comorbid CIndU. Compared with patients with standalone CSU, patients with CSU with comorbid CIndU were significantly younger, had earlier disease onset, longer disease duration, higher impact on quality of life, and a higher rate of concomitant allergic diseases. Moreover, patients with CSU with comorbid CIndU less often had features linked to autoimmune CSU such as angioedema, concomitant autoimmune diseases, eosinopenia, low levels of total IgE, and low total IgE combined with elevated anti-thyroid peroxidase IgG.

CONCLUSIONS

Autoimmune CSU may be less common in patients with comorbid CIndU than without, and comorbid CIndU may point to autoallergic CSU.

Is Atopic Dermatitis a Risk Factor for Thyroid Autoimmunity? - A Cross-Sectional Study from a Tertiary Care Center in India

Background

Because of the counter-regulation of Th1 and Th2 cells, Th1-type autoimmune diseases like thyroid autoimmunity and Th2-mediated allergic diseases like atopic dermatitis (AD) should occur in mutually exclusive populations. However, thyroid autoimmunity has been associated with chronic urticaria, and atopy is considered a cause of both AD and urticaria.

Objectives

To assess the frequency of thyroid autoimmunity in children with AD and to study the correlation between the clinical severity of AD using the SCORing Atopic Dermatitis (SCORAD) score, and biochemical parameters of serum immunoglobulin E (IgE), absolute eosinophil count, and vitamin D levels.

Materials and Methods

A hospital-based cross-sectional study was conducted, recruiting children (0-18 years) with AD. Patients on drugs affecting thyroid dysfunction and those with sick euthyroid syndrome or an immunodeficiency disorder were excluded. Clinical severity was assessed using SCORAD, and the thyroid profile, anti-thyroid peroxidase antibodies, antinuclear antibody (ANA), absolute eosinophil count, serum IgE, and vitamin D levels were measured.

Results

Thyroid autoimmunity was diagnosed in 18.9% (10/53) of children. There was a significant correlation between SCORAD and serum IgE (r = 0.432, P = 0.002) and absolute eosinophil count (r = 0.575, P = <0.001). There was a negative correlation between SCORAD and vitamin D levels (r = -0.373, P = 0.006).

Conclusions

Thyroid autoimmunity may be associated with AD, and a high index of suspicion is essential. Vitamin D also should be supplemented in children with AD as it is frequently found to be low, especially in severe cases. Multi-center case-control studies are required to determine the prevalence of thyroid autoimmunity in children with AD.

Allergic manifestations in women with silicone breast implants

INTRODUCTION

Silicone breast implants (SBI) result in immune dysregulation and are associated with autoimmune diseases. Recently, we reported dysregulated levels of IgG autoantibodies directed against G protein-coupled receptors (GPCRs) of the autonomic nervous system which were linked to the autoimmune dysautonomia in silicone breast implant illness (SBII).

AIMS

We aimed to explore the possible association between allergy with dysregulated IgE autoantibodies directed against GPCRs of the autonomic nervous system in women with SBI.

METHODS

Circulating levels of IgE autoantibodies against GPCRs of the autonomic nervous system (adrenergic, muscarinic, endothelin and angiotensin receptors) have been evaluated in women with SBIs who complained of allergic symptoms, and compared to subjects with SBI without allergic manifestations and to age-matched healthy women without SBI.

RESULTS

We report a significant dysregulation in three circulating autoantibodies: IgE-beta1 adrenergic receptor (B1AR), IgE-alpha 1 adrenergic receptor (A1AR) and IgE-muscarinic acetylcholine receptor type 1 (M1R) autoantibodies in women with SBI who complained of allergic symptoms.

CONCLUSIONS

Allergic reactions associated with SBI are not uncommon. Imbalance of circulating levels of IgE autoantibodies against GPCRs of the autonomic nervous system might play a role not only in allergic reactions, but also in other enigmatic aspects of SBII such as autoimmune dysautonomia.

Serum IgE anti-dsDNA autoantibodies in patients with proliferative lupus nephritis are associated with tubulointerstitial inflammation

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the overproduction of multiple autoantibodies. Lupus nephritis (LN), the most common cause of morbidity and mortality, requires early detection. However, only a limited number of serum biomarkers have been associated with the disease activity of LN. Serum IgE anti-dsDNA autoantibodies are prevalent in patients with SLE and may be associated with the pathogenesis of LN. In this study, serum samples from 88 patients with biopsy-proven proliferative LN were collected along with complete clinical and pathological data to investigate the clinical and pathological associations of anti-dsDNA IgE autoantibodies using ELISA. This study found that the prevalence of IgE anti-dsDNA autoantibodies in patients with proliferative LN was 38.6% (34/88). Patients with anti-dsDNA IgE autoantibodies were more prone to acute kidney injury (17/34 vs. 14/54; p = .025). Levels of anti-dsDNA IgE autoantibodies were associated with interstitial inflammation (r = 0.962, p = .017). Therefore, anti-dsDNA IgE autoantibody levels are associated with tubulointerstitial inflammation in patients with proliferative LN.

Immunoglobulin E autoantibodies in atopic dermatitis associate with Type-2 comorbidities and the atopic march

BACKGROUND

Autoreactive immunoglobulin E (IgE) antibodies to self-peptides within the epidermis have been identified in patients with atopic dermatitis (AD). Prevalence, concomitant diseases, patient characteristics, and risk factors of IgE autoantibody development remain elusive. We aimed to determine IgE autoantibodies in serum samples (n = 672) from well-characterized patients with AD and controls (1.2-88.9 years).

METHODS

Atopic dermatitis patients were sub-grouped in AD with comorbid Type-2 diseases ("AD + Type 2"; asthma, allergic rhinitis, food allergy, n = 431) or "solely AD" (n = 115). Also, subjects without AD but with Type-2 diseases ("atopic controls," n = 52) and non-atopic "healthy controls" (n = 74) were included. Total proteins from primary human keratinocytes were used for the immunoassay to detect IgE autoantibodies. Values were compared to already known positive and negative serum samples.

RESULTS

Immunoglobulin E autoantibodies were found in 15.0% (82/546) of all analyzed AD-patients. "AD + Type 2" showed a higher prevalence (16.4%) than "solely AD" (9.6%). "Atopic controls" (9.6%) were comparable with "solely AD" patients, while 2.7% of healthy controls showed IgE autoantibodies. Of those with high levels of IgE autoantibodies, 15 out of 16 were patients with "AD + Type 2". AD patients with IgE autoantibodies were younger than those without. Patients with IgE autoreactivity also displayed higher total serum IgE levels. Factors that affected IgE autoantibody development were as follows: birth between January and June, cesarean-section and diversity of domestic pets.

CONCLUSIONS

Immunoglobulin E autoantibodies in AD seem to associate with the presence of atopic comorbidities and environmental factors. The potential value of IgE autoantibodies as a predictive biomarker for the course of AD, including the atopic march, needs further exploration.

Autoreactive IgE: Pathogenic role and therapeutic target in autoimmune diseases

Autoimmunity is the break of tolerance to self-antigens that leads to organ-specific or systemic diseases often characterized by the presence of pathogenic autoreactive antibodies (AAb) produced by plasmablast and/or plasma cells. AAb are prevalent in the general population and not systematically associated with clinical symptoms. In contrast, in some individuals, these AAb are pathogenic and drive the development of signs and symptoms of antibody-mediated autoimmune diseases (AbAID). AAb production, isotype profiles, and glycosylations are promoted by pro-inflammatory triggers linked to genetic, environmental, and hormonal parameters. Recent evidence supports a role for pathogenic AAb of the IgE isotype in a number of AbAID. Autoreactive IgE can drive the activation of mast cells, basophils, and other types of FcεRI-bearing cells and may play a role in promoting autoantibody production and other pro-inflammatory pathways. In this review, we discuss the current knowledge on the pathogenicity of autoreactive IgE in AbAID and their status as therapeutic targets. We also highlight unresolved issues including the need for assays that reproducibly quantify IgE AAbs, to validate their diagnostic and prognostic value, and to further study their pathophysiological contributions to AbAID.

Clinical characteristics and outcome of autoimmune pancreatitis based on serum immunoglobulin G4 level: A single-center, retrospective cohort study

BACKGROUND

Autoimmune pancreatitis (AIP) has been linked with elevated immunoglobulin (Ig) G4 levels. The characteristics and outcomes of AIP based on serum markers have not been fully evaluated.

AIM

To compare clinical features, treatment efficacy, and outcome of AIP based on serum IgG4 levels and analyze predictors of relapse.

METHODS

A total of 213 patients with AIP were consecutively reviewed in our hospital from 2006 to 2021. According to the serum IgG4 level, all patients were divided into two groups, the abnormal group (n = 148) with a high level of IgG4 [> 2 × upper limit of normal (ULN)] and the normal group (n = 65). The t-test or Mann-Whitney U test was used to compare continuous variables. Categorical parameters were compared by the χ2 test or Fisher's exact test. Kaplan-Meier curves and log-rank tests were established to assess the cumulative relapse rates. Univariate and multivariate analyses were used to investigate potential risk factors of AIP relapse.

RESULTS

Compared with the normal group, the abnormal group had a higher average male age (60.3 ± 10.4 vs 56.5 ± 12.9 years, P = 0.047); higher level of serum total protein (72.5 ± 7.9 g/L vs 67.2 ± 7.5 g/L, P < 0.001), IgG4 (1420.5 ± 1110.9 mg/dL vs 252.7 ± 106.6 mg/dL, P < 0.001), and IgE (635.6 ± 958.1 IU/mL vs 231.7 ± 352.5 IU/mL, P = 0.002); and a lower level of serum complement C3 (100.6 ± 36.2 mg/dL vs 119.0 ± 45.7 mg/dL, P = 0.050). In addition, a lower number of cases with abnormal pancreatic duct and pancreatic atrophy (23.6% vs 37.9%, P = 0.045; 1.6% vs 8.6%, P = 0.020, respectively) and a higher rate of relapse (17.6% vs 6.2%, P = 0.030) were seen in the abnormal group. Multivariate analyses revealed that serum IgG4 [(> 2 × ULN), hazard ratio (HR): 3.583; 95% confidence interval (CI): 1.218-10.545; P = 0.020] and IgA (> 1 × ULN; HR: 5.908; 95%CI: 1.199-29.120; P = 0.029) and age > 55 years (HR: 2.383; 95%CI: 1.056-5.378; P = 0.036) were independent risk factors of relapse.

CONCLUSION

AIP patients with high IgG4 levels have clinical features including a more active immune system and higher relapse rate. Several factors, such as IgG4 and IgA, are associated with relapse.

An Investigation of the Relationship Between Isolated Anti-dense Fine-Speckled 70 Autoantibodies and Allergen-Specific Immunoglobulin E

Background Although the mechanisms of the formation of anti-dense fine-speckled 70 (anti-DFS70) antibodies are not fully known, there is evidence in the literature that allergic reactions may play a role in their formation. Immunoglobulin E (IgE)-mediated immunopathological mechanisms are increasingly being elucidated in diseases such as atopic dermatitis and urticaria-related diseases. We aimed to reveal its relationship with anti-DFS70 in allergen-sensitive patients with positive specific IgE (sIgE) levels. Methodology The study included samples of 758 patients who underwent antinuclear antibody (ANA) screening and allergen-sIgE testing between January 2019 and January 2022. Patients' clinical diagnoses were retrospectively obtained from the hospital information management system. ANA was tested according to the instructions of the manufacturer by the indirect immunofluorescent antibody method using HEp-2 cell substrates (Euroimmun Luebeck, Germany). Allergen-sIgE was determined by chemiluminescence on the Immulite 2000 XPI system (Siemens Healthcare Diagnostics Products GmbH, Marburg, Germany) according to the instructions of the manufacturer. Results ANA pattern was detected in 74 samples included in the study. ANA-positive patients were divided into DFS70 (+) and DFS70 (-) groups. A statistically significant increase in the DFS70 pattern was observed in patients with a positive allergen-sIgE test (p < 0.0001). Both allergen-sIgE and DFS70 positivity were statistically significant in younger age groups (p < 0.05). The most common diagnosis was urticaria-related conditions in 23 (31%) patients with a positive allergy test. Conclusions Our study shows that the positivity of the DFS70 pattern is increased in allergen-sensitive patients. Therefore, the allergen-sIgE-mediated allergic disease should be considered in patients with isolated anti-DSF70. Studies with related disease groups are needed to determine whether there is a relationship between anti-DFS70 and allergy-related disease in these patients. If an immunopathological mechanism is not found, these false-positive results can be considered clinically insignificant, and unnecessary consultations can be avoided.

A focused report on progestogen hypersensitivity

INTRODUCTION

Progestogen Hypersensitivity (PH) is caused by increased sensitivity to either exogenous or endogenous progestogens. It is characterized by recurrent cutaneous eruptions including erythema multiforme, eczema, urticaria, and angioedema, which may be associated with systemic symptoms including asthma and anaphylaxis.

AREAS COVERED

Symptoms may be persistent or cyclical, coinciding with progestogen levels. With increased use of oral contraceptives and hormonal treatments for fertility, the prevalence of PH is expected to continuously increase. Several proposed immunological mechanisms, diagnostics, and treatment modalities have been proposed. Most treatments focus on suppressing ovulation and progesterone secretion or inducing tolerance through progesterone desensitization.

EXPERT OPINION

Although there has been increased recognition both clinically and in the medical literature, there is still a general lack of knowledge of PH and its clinical features in the medical community. An improved understanding of the underlying pathophysiology as well as more available commercial testis, such as ELISA that accurately measures specific IgE to progesterone, are expected to broaden and improve opportunities for disease recognition and symptom control. It is essential for physicians across specialties to recognize how to diagnose PH and either manage this condition or refer these patients to a specialist with experience treating PH.

Immunoglobulin E and G autoantibodies against eosinophil proteins in children and adults with asthma and healthy subjects

Background

Autoimmune IgG response has been described in the pathogenesis of asthma in adults, but IgE autoimmunity has been little explored. Considering high levels of blood eosinophils and immunoglobulin E in asthmatic patients, the possibility of IgE autoantibody response to eosinophil proteins arises.

Objective

To explore the presence of IgE and IgG autoantibodies against Eosinophil peroxidase (EPX) and Eosinophil cationic protein (ECP).

Methods

Three steps were followed: 1) The frequency of IgE and IgG autoantibodies against EPX and ECP was investigated among asthmatic and healthy subjects. 2) The ability of IgE autoantibodies to induce an inflammatory response (basophil activation) was performed. 3) The capacity of autoantibodies to identify patients with severe asthma was evaluated.

Results

Asthmatic and healthy subjects had IgE and IgG autoantibodies against EPX and ECP. Anti-EPX IgE was significantly higher in asthmatic patients. Severe asthmatic patients had a higher frequency and higher levels of IgE and IgG autoantibodies compared to healthy subjects. There was not a correlation between autoantibodies and blood eosinophils. Children younger than 14 years of age had IgE and IgG autoantibodies against to EPX and ECP. IgE autoantibodies to EPX and ECP induced basophil activation in asthmatic patients.

Conclusion

In this study, we identify for the first time IgE autoantibodies against EPX and ECP in adults and children patients with asthma; IgE and IgG autoantibodies against EPX and ECP could serve as a predictive biomarker of the clinical severity.

Ragweed Major Allergen Amb a 11 Recombinant Production and Clinical Implications

Ragweed pollen is highly allergenic and elicits type I hypersensitivity reactions in the exposed populations. Amb a 11 is a recently discovered component of this pollen, and its biological role in allergy is still being researched. In our study, ragweed allergy patients were recruited prospectively over a three-year period; a comprehensive questionnaire was administered, and sera were collected and stored. The production of recombinant Amb a 11 was achieved in parallel with patients' recruitment. The gene coding for mature protein was inserted in E. coli and in Sf9 Spodoptera frugiperda cells. The recombinant allergens (designated eAmb a 11 and iAmb a 11) were tested for His-tag presence in Western blot. IgE reactivity was evaluated in 150 patients' sera for both recombinant allergen forms in ELISA, with 5 positive sera being tested further by hRBL (humanized rat basophilic leukemia) hexosaminidase release assay. Both allergen forms were proven to be IgE-reactive His-tagged proteins, with an extensive overlap of positive sera (92 toward the former recombinant allergen, 100 toward the latter) and an overall Amb a 11 sensitization prevalence estimated at 68.67%. The hRBL mediator release assay revealed a significant, slightly weaker effect of recombinant allergens when compared with nAmb a 1. Sensitization to this major allergen appears to be associated with more severe asthma symptoms (OR = 4.71, 95% CI = 1.81-12.21). In conclusion, recombinant Amb a 11 is a bona fide allergen, which is IgE-reactive and an inducer of hRBL degranulation. It is an important IgE-reactive component from ragweed pollen, with high IgE sensitization prevalence in the sample population and allergenicity of the recombinant allergen comparable to Amb a 1.

Lupus Nephritis in an Adolescent Girl With Hyper-Immunoglobulin E

We report the case of an adolescent girl with frequent hospital admissions for severe eczematous skin rashes with recurrent epistaxis and chest infections. Investigations revealed persistent severely elevated serum total immunoglobulin E (IgE) levels but normal levels of other immunoglobulins, suggesting hyper-IgE syndrome. The first skin biopsy revealed superficial dermatophytic dermatitis (tinea corpora). Another biopsy performed after six months revealed a prominent basement membrane with dermal mucin, suggesting an underlying autoimmune disease. Her condition was complicated by proteinuria, hematuria, hypertension, and edema. A kidney biopsy revealed class IV lupus nephritis, according to the International Society of Nephrology/Renal Pathology Society (ISN/RPS). Based on the American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) criteria, she was diagnosed with systemic lupus erythematosus (SLE). She was first administered with intravenous pulse methylprednisolone (600 mg/m²) for three consecutive days, followed by oral prednisolone (40 mg/m²) daily, mycophenolate mofetil tablets (600 mg/m²/dose) twice daily, hydroxychloroquine (200 mg) once daily, and three classes of antihypertensive medications. She maintained normal renal functions with no lupus morbidity for 24 months, then rapidly progressed to end-stage kidney disease, and was then started on three to four sessions of regular hemodialysis per week. Hyper-IgE is known to be a marker of immune dysregulation as it facilitates the generation of immune complexes (ICs) that mediate lupus nephritis and juvenile SLE. Regardless of the different factors that are impacting the production of IgE, the present case illustrated that juvenile patients with SLE may have increased IgE levels, indicating that higher IgE levels might have a role in lupus pathogenesis and prognosis. The mechanisms regarding the increased levels of IgE in subjects with lupus need further investigation. Further studies are thus required to assess the incidence, prognosis, and possible new specific management for hyper-IgE in juvenile SLE.

Allergenic food protein consumption is associated with systemic IgG antibody responses in non-allergic individuals

Although food-directed immunoglobulin E (IgE) has been studied in the context of allergies, the prevalence and magnitude of IgG responses against dietary antigens are incompletely characterized in the general population. Here, we measured IgG binding against food and environmental antigens obtained from allergen databases and the immune epitope database (IEDB), represented in a phage displayed library of 58,233 peptides. By profiling blood samples of a large cohort representing the average adult Israeli population (n = 1,003), we showed that many food antigens elicited systemic IgG in up to 50% of individuals. Dietary intake of specific food protein correlated with antibody binding, suggesting that diet can shape the IgG epitope repertoire. Our work documents abundant systemic IgG responses against food antigens and provides a reference map of the exact immunogenic epitopes on a population scale, laying the foundation to unravel the role of food- and environmental antigen-directed antibody binding in disease contexts.

Comorbidities of Chronic Urticaria: A glimpse into a complex relationship

Chronic Urticaria (CU) is a chronic inflammatory, predominantly mast cell-driven disease, characterized by the development of wheals and/or angioedema for more than 6 weeks. It affects approximately 1%-5% of the total population worldwide and imposes a substantial burden on health-related quality of life, significantly affecting patients' daily life. The economic impact on the health system is also not negligible, with an estimated cost per patient per year of approximately 2.000 $ in the United States. Although the underlying pathophysiology is not fully explored, autoimmune mechanisms have been proposed, including type I ("autoallergy" by means of autoantibodies to self-antigens) and type IIb (autoimmunity). Atopic, autoimmune, and psychiatric disorders are prevalent comorbidities in both children and adults with Chronic Spontaneous Urticaria (CSU). Although malignancies, cardiovascular diseases and other comorbidities have also been reported as associated diseases in patients with CSU, data remain scarce. It is still unknown whether the aforementioned comorbidities share common pathophysiological mechanisms with specific endotypes of CSU. The current review aims to overview current data on comorbidities of CU, and furthermore to comment on the potential linked pathways underlying these diseases.

Sleep deprivation and immunoglobulin E level

Objectives

Sleep deprivation is a common issue for modern people and leads to many morbidities and mortality. Some papers also suspected the relationship between Immunoglobulin E (IgE) level and sleep deprivation. The purpose of this article is to make the vicious circle between serum IgE level and sleep deprivation clear.

Materials and methods

In this study, we included 4,460 population aged around 48 years old respective 2,145 males and 2,315 females enrolled in the National Health and Nutrition Examination Survey (NHANES). Sleep durations were recorded, in hours, in whole numbers by the participants. The levels of total IgE were measured by anti-IgE. All procedures were analyzed using SPSS version 18 (SPSS, Inc., Chicago, IL, USA).

Result

The statistical significance between higher IgE level and ≤5 h sleep duration was noted (Beta coefficients: 64.04, 95% confidence interval (CI): 2.35, 125.72, P = 0.042). In sex difference, the correlation between short sleep duration and high serum IgE levels was noted in male [Beta coefficients: 120.225 (P = 0.008)] but not in female. There were no positive findings in the ethnicity-based correlation between serum IgE levels and sleep duration.

Conclusion

This study indicated that short sleep duration (≤5 h) is associated with higher serum IgE levels, especially in men. Further longitudinal investigations concerning the effect of sleep deprivation on serum IgE might provide a better explanation for the pathophysiology underlying autoimmune disease and sleep deprivation.

Ligelizumab impairs IgE ‐binding to plasmacytoid dendritic cells more potently than omalizumab and restores IFN ‐α production and FOXP3 + Treg generation

BACKGROUND

Ligelizumab is an anti-IgE monoclonal antibody binding IgE with higher affinity than omalizumab that is under clinical investigation for several IgE-mediated diseases. We previously showed that omalizumab removes IgE bound to FcεRI on plasmacytoid dendritic cells (pDCs) and restores their ability to produce IFN-α and regulatory T cells (Tregs). The aim of this work is to investigate the capacity of ligelizumab to regulate functional properties of pDCs in comparison with omalizumab.

METHODS

pDCs were isolated from atopic donors and IgE was detached from FcεRI on pDCs with designed ankyrin repeat protein (DARPin) bi53-79. pDCs were resensitized with IgE alone or in the presence of ligelizumab or omalizumab prior to IgE-FcεRI crosslinking and Toll-like receptor 9 (TLR9) stimulation. Flow cytometry, ELISA, coculture experiments and intranuclear staining were performed to determine cytokine production and Treg generation. An antigen-specific model of resensitization and IgE-crosslinking was also performed.

RESULTS

The levels of serum total free IgE show a non-linear positive correlation with the frequency of IgE⁺ pDCs displaying IgE bound to FcεRI within the 43 individual donors included in the study. Ligelizumab displays stronger capacity than omalizumab to block the binding of free IgE to FcεRI on human pDCs, resulting in a greater restoration of TLR9-L-induced IFN-α production. Ligelizumab also restores the ability of pDCs to generate FOXP3⁺ Tregs as previously reported for omalizumab.

CONCLUSIONS

The uncovered novel molecular mechanisms of ligelizumab to regulate functional properties of pDCs from atopic donors might have important clinical implications for anti-IgE treatments in different IgE-mediated diseases.

Regulatory T cells and immunoglobulin E: A new therapeutic link for autoimmunity?

Autoimmune diseases have a prevalence of approximately 7 to 9% and are classified as either organ-specific diseases, including type I diabetes, multiple sclerosis, inflammatory bowel disease and myasthenia gravis, or systemic diseases, including systemic lupus erythematosus, rheumatoid arthritis and Sjögren's syndrome. While many advancements have been made in understanding of the mechanisms of autoimmune disease, including the nature of self-tolerance and its breakdown, there remain unmet needs in terms of effective and highly targeted treatments. T regulatory cells (Tregs) are key mediators of peripheral tolerance and are implicated in many autoimmune diseases, either as a result of reduced numbers or altered function. Tregs may be broadly divided into those generated in the thymus (tTregs) and those generated in the periphery (pTregs). Tregs target many different immune cell subsets and tissues to suppress excessive inflammation and to support tissue repair and homeostasis: there is a fine balance between Treg cell stability and the plasticity that is required to adjust Tregs' regulatory purposes to particular immune responses. The central role of immunoglobulin E (IgE) in allergic disease is well recognized, and it is becoming increasingly apparent that this immunoglobulin also has a wider role encompassing other diseases including autoimmune disease. Anti-IgE treatment restores the capacity of plasmacytoid dendritic cells (pDCs) impaired by IgE- high-affinity IgE receptor (FcεR1) cross-linking to induce Tregs in vitro in atopic patients. The finding that anti-IgE therapy restores Treg cell homeostasis, and that this mechanism is associated with clinical improvement in asthma and chronic spontaneous urticaria suggests that anti-IgE therapy may also have a potential role in the treatment of autoimmune diseases in which Tregs are involved.

IgE receptor responsiveness of basophils in chronic inducible urticaria

Introduction

Chronic inducible urticaria (CIndU) is a subgroup of chronic urticaria induced by a specific stimulus. We evaluated basophil characteristics in patients with CIndU and compared with those in patients with chronic spontaneous urticaria (CSU) and healthy controls (HCs).

Methods

Blood was collected from patients, and a basophil activation test (BAT) was performed. Basophil responsiveness and surface marker expression in patients with CIndU were compared with those in patients with CSU and HCs. For some patients with CIndU, blood was collected before and after wheals were induced. In these cases, we compared the responsiveness of basophils before and after the appearance of wheals.

Result

HCs (n=23) and patients with CIndU (n=24) or CSU (n=38) were enrolled in the study. The degree of basophil activation at steady state in patients with CIndU was higher than in HCs. Basophil responsiveness via high-affinity IgE receptor (FcϵRI) stimulation with anti-IgE or anti-FcϵRI antibody in patients with CIndU was equivalent to that in HCs, and higher than that in patients with CSU. No abnormalities in IgE and FcϵRI expressions on the surface of basophils in patients with CIndU were observed. When we induced wheals in some patients with CIndU and performed a BAT before and after the appearance of wheals, no significant changes were found.

Conclusion

Peripheral blood basophils in CIndU were slightly activated at steady state, but no abnormalities in basophil responsiveness. In future, a higher number of cases should be enrolled to confirm the role of basophils and refine therapeutic targets for CIndU.

Chronic urticaria associated with lung adenocarcinoma — a paraneoplastic manifestation: A case report and literature review

BACKGROUND

Urticaria is one of the most common causes of emergency room visits. It is defined as an acute inflammatory dermatosis, characterized by localized degranulation of mast cells, with consequent dermal microvascular and formation of edematous and pruritic plaques called hives. Urticaria affects the skin and tissues of the superficial mucosa. Sometimes it is accompanied by angioedema, which is characterized by deeper edema of the dermis and subcutaneous cellular tissue known as the urticarial-angioedema syndrome. About 15%-25% of the general population has suffered at least one type of urticaria at some point during their lifetime and hyperpermeability estimated at 7.6%-16% and has experienced acute urticaria that is usually self-limited and spontaneously resolves without requiring medical attention.

CASE SUMMARY

We present the case of a young male patient who was referred to our department with a clinical picture of 4 mo of pruritus associated with hives of variable sizes, irregular borders, with interlesional confluence, that were non-painful, without involvement of the palms and soles of the feet but with a tendency to progression in a generalized manner. He had multiple emergency room visits and poor response to antihistamines and systemic corticosteroids. Imaging studies demonstrated nodules in the lower lingula segment, at the level of the greater fissure and in the anterior contour of the left anterior basal segment associated with parahiliar adenopathies in the absence of findings suggestive of infectious or autoimmune etiology. Segmental lobectomy was performed by thoracoscopy with resection of a lung nodule in the lingula and biopsy of the para-aortic mediastinal ganglion. The histopathological report showed the presence of poorly differentiated invasive adenocarcinoma with a solid morphological and acinar pattern with immunohistochemical description of lung tissue that expresses strong positive and diffuse reaction for thyroid transcription factor 1 (TTF-1) with negativity to P40 for a histopathological diagnosis of malignant epithelial neoplasia with expression of infiltrating adenocarcinoma. Spontaneous chronic urticaria is considered possibly secondary to lung adenocarcinoma.

CONCLUSION

Chronic spontaneous urticaria is considered a paraneoplastic dermatosis with a controversial association in the literature. In the presented case, a young patient presented with chronic refractory urticaria and after an exhaustive clinical work-up was found to have a diagnosis of poorly differentiated lung adenocarcinoma with high expression of TTF-1. According to the Curth criteria, the urticaria presented by the patient is related to the oncological diagnosis. In addition, the high expression of TTF-1 documented in this case could be acting as an autoantigen that would cause chronic spontaneous urticaria. Further research evaluating a causal relationship between the TFF-1 protein and urticaria in lung cancer is needed.

Autoantibodies to IgE can induce the release of proinflammatory and vasoactive mediators from human cardiac mast cells

Mast cells are multifunctional immune cells with complex roles in tissue homeostasis and disease. Cardiac mast cells (HCMCs) are strategically located within the human myocardium, in atherosclerotic plaques, in proximity to nerves, and in the aortic valve. HCMCs express the high-affinity receptor (FcεRI) for IgE and can be activated by anti-IgE and anti-FcεRI. Autoantibodies to IgE and/or FcεRI have been found in the serum of patients with a variety of immune disorders. We have compared the effects of different preparations of IgG anti-IgE obtained from patients with atopic dermatitis (AD) with rabbit IgG anti-IgE on the release of preformed (histamine and tryptase) and lipid mediators [prostaglandin D₂ (PGD₂) and cysteinyl leukotriene C₄ (LTC₄)] from HCMCs. Functional human IgG anti-IgE from one out of six AD donors and rabbit IgG anti-IgE induced the release of preformed (histamine, tryptase) and de novo synthesized mediators (PGD₂ and LTC₄) from HCMCs. Human IgG anti-IgE was more potent than rabbit IgG anti-IgE in inducing proinflammatory mediators from HCMCs. Human monoclonal IgE was a competitive antagonist of both human and rabbit IgG anti-IgE. Although functional anti-IgE autoantibodies rarely occur in patients with AD, when present, they can powerfully activate the release of proinflammatory and vasoactive mediators from HCMCs.

CT-M8 Mice: A New Mouse Model Demonstrates That Basophils Have a Nonredundant Role in Lupus-Like Disease Development

Tissue-specific mouse models are essential tools to decipher the role of each cell compartment and/or their expressed genes in the pathophysiology of diseases. Here, we describe a new knock-in mouse model allowing expression of both the fluorescent protein tdTomato and the CRE recombinase selectively in the basophil compartment under the control of the Mcpt8 gene. These “CT-M8” mice did not show any abnormalities in their peripheral distribution of major immune cell populations nor their basophil function. CT-M8 mice allowed the identification of basophils by immunofluorescence and flow cytometry and basophil-specific Cre-mediated floxed gene deletion. Breeding of our CT-M8 mice with the ROSA26^{flox-stop-DTA} mice led to the generation of basophil-deficient mice with no detectable abnormalities in other cell compartments. These mice were then used to document basophil involvement in systemic lupus erythematosus (SLE) pathophysiology since we previously reported by transient depletion of these cells during the course of an ongoing disease that they support and amplify autoantibody production in two distinct lupus-like mouse models (Lyn^−/− and pristane-induced). Here, constitutive basophil deficiency prevented pristane-induced lupus-like disease development by limiting autoantibody titers and renal damages. Therefore, basophils have a nonredundant role in pristane-induced lupus-like disease and are involved in both its induction and amplification. This CT-M8 new mouse model will allow us to finely decipher the role of basophils and their expressed genes in health and disease.

IgG Autoantibodies Against IgE from Atopic Dermatitis Can Induce the Release of Cytokines and Proinflammatory Mediators from Basophils and Mast Cells

IgE-mediated release of proinflammatory mediators and cytokines from basophils and mast cells is a central event in allergic disorders. Several groups of investigators have demonstrated the presence of autoantibodies against IgE and/or FcεRI in patients with chronic spontaneous urticaria. By contrast, the prevalence and functional activity of anti-IgE autoantibodies in atopic dermatitis (AD) are largely unknown. We evaluated the ability of IgG anti-IgE from patients with AD to induce the in vitro IgE-dependent activation of human basophils and skin and lung mast cells. Different preparations of IgG anti-IgE purified from patients with AD and rabbit IgG anti-IgE were compared for their triggering effects on the in vitro release of histamine and type 2 cytokines (IL-4, IL-13) from basophils and of histamine and lipid mediators (prostaglandin D₂ and cysteinyl leukotriene C₄) from human skin and lung mast cells. One preparation of human IgG anti-IgE out of six patients with AD induced histamine release from basophils, skin and lung mast cells. This preparation of human IgG anti-IgE induced the secretion of cytokines and eicosanoids from basophils and mast cells, respectively. Human monoclonal IgE was a competitive antagonist of both human and rabbit IgG anti-IgE. Human anti-IgE was more potent than rabbit anti-IgE for IL-4 and IL-13 production by basophils and histamine, prostaglandin D₂ and leukotriene C₄ release from mast cells. Functional anti-IgE autoantibodies rarely occur in patients with AD. When present, they induce the release of proinflammatory mediators and cytokines from basophils and mast cells, thereby possibly contributing to sustained IgE-dependent inflammation in at least a subset of patients with this disorder.

Current and Future Approaches in Management of Chronic Spontaneous Urticaria Using Anti-IgE Antibodies

Chronic spontaneous urticaria (CSU) considerably alters patients’ quality of life, often for extended periods, due to pruriginous skin lesions, impaired sleep, unexpected development of angioedema, and failure of conventional treatments in properly controlling signs and symptoms. Recent research focused on the development of new therapeutic agents with higher efficacy. Although the production of specific immunoglobulin E (IgE) antibodies against certain allergens is not a characteristic of the disease, treatment with omalizumab, a monoclonal anti-IgE antibody, proved efficient and safe in patients with moderate to severe chronic spontaneous urticaria uncontrolled by H1-antihistamines. Ligelizumab, a high-affinity monoclonal anti-IgE antibody, may also efficiently relieve symptoms of unresponsive chronic urticaria to standard therapies. This comprehensive review aims to present recently acquired knowledge on managing chronic spontaneous urticaria with new anti-IgE antibodies. We conducted extensive research on the main databases (PubMed, Google Scholar, and Web of Science) with no restrictions on the years covered, using the search terms “anti-IgE antibodies”, “omalizumab”, “ligelizumab”, and “chronic spontaneous urticaria”. The inclusion criteria were English written articles, and the exclusion criteria were animal-related studies. ClinicalTrials.gov was also reviewed for recent relevant clinical trials related to CSU treatment. CSU is a challenging disease with a significant effect on patients’ quality of life. Current therapies often fail to control signs and symptoms, and additional treatment is needed. New biologic therapies against IgE antibodies and FcεRIα receptors are currently under investigation in advanced clinical trials. We reviewed recently published data on CSU management using these novel treatments. The development of new and improved treatments for CSU will lead to a more personalized therapeutical approach for patients and provide guidance for physicians in better understanding disease mechanisms. However, some agents are still in clinical trials, and more research is needed to establish the safety and efficacy of these treatments.

Autoimmune chronic spontaneous urticaria

Chronic spontaneous urticaria (CSU) is a debilitating mast cell-driven disease characterized by recurrent wheals and/or angioedema. Substantial progress has been made in dissecting the 2 main autoimmune mechanisms that drive the pathogenesis of CSU. Type I autoimmune (autoallergic) CSU is associated with IgE antibodies against autoantigens, for example, thyroid peroxidase and IL-24. Type IIb autoimmune CSU is mediated by autoantibodies that activate mast cells, for example, via IgE and FcεRI, and is present in less than 10% of patients with CSU when strict criteria are used, that is, triple positivity of autologous serum skin test, immunoassays for IgG autoantibodies, and basophil activation tests. A subpopulation of patients with CSU has both types. Type IIb autoimmune CSU is characterized by higher disease severity, concomitant autoimmune diseases, low levels of total IgE, elevated levels of IgG-anti-thyroid peroxidase, basopenia, eosinopenia, poor response to antihistamines and to omalizumab, and a good response to cyclosporine. Novel targeted therapies for CSU are under development such as ligelizumab, an anti-IgE, fenebrutinib and remibrutinib, Bruton's tyrosine kinase inhibitors, and dupilumab, an anti-IL-4Rα. Further studies should investigate the overlap between autoallergic and type IIb autoimmune CSU, optimize the diagnosis of both autoimmune endotypes using easy-to-perform, noninvasive, and inexpensive markers, and assess differences in response to therapy.

Immunoglobulin E response in health and disease beyond allergic disorders

Immunoglobulin E is the latest discovered of immunoglobulin family and has been long associated with anaphylaxis and worm expulsion. Immunoglobulin E, along with mast cells, basophils, and eosinophils, is also a hallmark of type 2 immunity which is dysregulated in numerous diseases such as asthma, rhinitis, atopic dermatitis, and eosinophilic esophagitis in addition to anaphylaxis as aforementioned. However, recent advances have shed light on IgE regulation and memory explaining the low level of free IgE, the scarcity of IgE plasma cells that are mainly short live and the absence of IgE memory B cells in homeostatic conditions. Furthermore, IgE was implicated in inflammatory conditions beyond allergic disorders where IgE-mediated facilitated antigen presentation can enhance cellular and humoral response against autoantigens in systemic lupus or chronic urticaria leading to more severe disease and even against neoantigen facilitating tumor cell lysis. At last, IgE was unexpectedly associated with allograft rejection or atheromatous cardiovascular diseases where precise mechanisms remain to be deciphered. The purpose of this review is to summarize these recent advances in IgE regulation, biology, and physiopathology beyond allergic diseases opening whole new fields of IgE biology to explore.

Linear IgA/IgG bullous dermatosis successfully treated with omalizumab: A case report

Linear IgA/IgG bullous dermatosis (LAGBD) is a rare, autoimmune blistering skin disease. We report a case of LAGBD in a 70-year-old woman. All common treatments were discontinued due to side effects or lack of treatment response. The patient was successfully treated with omalizumab which cleared her lesions after three months.

Emerging treatments for chronic urticaria

INTRODUCTION

Across the globe, chronic urticaria (CU), i.e. chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CINDU), is common, long-persisting and difficult to manage. Still, at least one-fifth is not sufficiently controlled by guideline-recommended treatment with H1-antihistamines and add-on therapy with the anti-IgE monoclonal antibody omalizumab.

AREAS COVERED

Using PubMed, ClinicalTrials.gov, Congress websites, and websites of the manufacturers, this review explored the pipeline, namely anti-IgE-, anti-cytokine-, anti-receptor biologics, and small molecules, in clinical development for CU.

EXPERT OPINION

The CU pipeline is promising. While three omalizumab biosimilars are investigated, the assumed early approval of ligelizumab will expand the effective and safe anti-IgE approach observed with omalizumab. For other anti-IgEs like UB-221, the development is behind. Data are too limited so far to clearly define the role of anti-cytokine and anti-cytokine receptor biologics such as dupilumab, tezepelumab, mepolizumab, benralizumab, and CDX-0159, of which only dupilumab is actually investigated in phase 3. Among three selective oral BTK inhibitors, remibrutinib, rilzabrutinib, and fenebrutinib, the development of remibrutinib is most advanced (phase 3). As the pipeline addresses different targets, study results will give deeper insights into the pathomechanisms of CU. Hopefully, in the next future additional approved and also more targeted approaches will be available.

Human IgE does not bind to human FcRn

The neonatal Fc receptor (FcRn) is known to mediate placental transfer of IgG from mother to unborn. IgE is widely known for triggering immune responses to environmental antigens. Recent evidence suggests FcRn-mediated transplacental passage of IgE during pregnancy. However, direct interaction of FcRn and IgE was not investigated. Here, we compared binding of human IgE and IgG variants to recombinant soluble human FcRn with β2-microglobulin (sFcRn) in surface plasmon resonance (SPR) at pH 7.4 and pH 6.0. No interaction was found between human IgE and human sFcRn. These results imply that FcRn can only transport IgE indirectly, and thereby possibly transfer allergenic sensitivity from mother to fetus.

High Serum Total IgE at Admission Is Associated with Coronary Artery Lesions in Children with Kawasaki Disease

Kawasaki disease (KD) is associated with allergy. As immunoglobulin E (IgE), a key element of allergic reactions, is related with coronary heart disease, we evaluated the serum total IgE levels, and investigated its clinical relevance in 339 children with KD. These patients were classified as high IgE group and normal IgE group according to the reference value of IgE. Serum IgE levels in the high group (279.76 ± 202.54 IU/mL) significantly increased compared with the normal group (5.51 ± 15.79 IU/mL) (p < 0.001). There were also no significant differences in the frequency of major clinical manifestation between the two groups. The number of patients who developed coronary artery lesions (CALs) was significantly higher in the high group (p = 0.004), and the serum levels of IgE were also markedly higher in the KD patients with CALs than in patients without CALs (p = 0.002). High total serum IgE was an independent prognostic for CALs in the multivariate analysis. In conclusion, serum IgE levels may be associated with CALs in children with KD.

Beyond Titer: Expanding the Scope of Clinical Autoantibody Testing

Background

Autoantibodies that bind self-antigens are a hallmark of autoimmune diseases, but can also be present in healthy individuals. Clinical assays that detect and titer antigen-specific autoantibodies are an important component of the diagnosis and monitoring of autoimmune diseases. Autoantibodies may contribute to disease pathogenesis via effector functions that are dictated by both the antigen-binding site and constant domain.

Content

In this review, we discuss features of antibodies, in addition to antigen-binding specificity, which determine effector function. These features include class, subclass, allotype, and glycosylation. We discuss emerging data indicating that analysis of these antibody features may be informative for diagnosis and monitoring of autoimmune diseases. We also consider methodologies to interrogate these features and consider how they could be implemented in the clinical laboratory.

Summary

Future autoantibody assays may incorporate assessment of additional antibody features that contribute to autoimmune disease pathogenesis and provide added clinical value.

Contribution of Dysregulated B-Cells and IgE Antibody Responses to Multiple Sclerosis

Multiple sclerosis (MS), a debilitating autoimmune inflammatory disease that affects the brain and spinal cord, causes demyelination of neurons, axonal damage, and neurodegeneration. MS and the murine experimental autoimmune encephalomyelitis (EAE) model have been viewed mainly as T-cell-mediated diseases. Emerging data have suggested the contribution of B-cells and autoantibodies to the disease progression. However, the underlying mechanisms by which dysregulated B-cells and antibody response promote MS and EAE remain largely unclear. Here, we provide an updated review of this specific subject by including B-cell biology and the role of B-cells in triggering autoimmune neuroinflammation with a focus on the regulation of antibody-producing B-cells. We will then discuss the role of a specific type of antibody, IgE, as it relates to the potential regulation of microglia and macrophage activation, autoimmunity and MS/EAE development. This knowledge can be utilized to develop new and effective therapeutic approaches to MS, which fits the scope of the Research Topic "Immune Mechanism in White Matter Lesions: Clinical and Pathophysiological Implications".

The ingenious mast cell: Contemporary insights into mast cell behavior and function

Mast cells are (in)famous for their role in allergic diseases, but the physiological and pathophysiological roles of this ingenious cell are still not fully understood. Mast cells are important for homeostasis and surveillance of the human system, recognizing both endogenous and exogenous agents, which induce release of a variety of mediators acting on both immune and non-immune cells, including nerve cells, fibroblasts, endothelial cells, smooth muscle cells, and epithelial cells. During recent years, clinical and experimental studies on human mast cells, as well as experiments using animal models, have resulted in many discoveries that help decipher the function of mast cells in health and disease. In this review, we focus particularly on new insights into mast cell biology, with a focus on mast cell development, recruitment, heterogeneity, and reactivity. We also highlight the development in our understanding of mast cell-driven diseases and discuss the development of novel strategies to treat such conditions.

Predictive significance of anti-FVIII immunoglobulin patterns on bleeding phenotype and outcomes in acquired hemophilia A: Results from the Quebec Reference Center for Inhibitors

BACKGROUND

Acquired hemophilia A (AHA) is a potentially life-threatening bleeding disorder caused by factor VIII (FVIII) autoantibodies, involving various immunoglobulin (Ig) isotypes and IgG subclasses.

OBJECTIVES

We analyzed the profile of Ig against FVIII in patients with AHA to identify Ig patterns predictive of bleeding phenotype and outcomes.

PATIENTS/METHODS

Ig detection and titration were determined by enzyme-linked immunosorbent assay (ELISA) at disease presentation in a cohort of 66 subjects from the Quebec Reference Centre for Inhibitors registry.

RESULTS

Most of plasma samples analyzed (97%) contained multiple anti-FVIII Ig isotypes and IgG subclasses, IgG(1,2,3,4) (24.2%), [IgG(1,2,3,4),IgA] (16.7%) and IgG(2.4) (13.6%) being the most prevalent combinations of Ig detected. AHA patients who presented with IgA antibodies were more likely to have an associated auto-immune disease (p = .049). The presence of IgG4-was associated with bleeding symptoms at presentation (p = .002). IgG1-positive patients were more likely to require transfusions with red packed cell (p = .014) whereas IgM detection was associated with a higher probability of death linked to AHA (p = .011).

CONCLUSION

The Ig pattern of AHA patients at diagnosis is widely heterogeneous and is at least partially associated with some underlying conditions. Our data supports the differential predictive significance for IgG1, IgG4 and IgM on bleeding severity and suggests that the early determination of Ig profile may help to identify AHA patients at higher risk of poorer outcomes.

Pollens in therapeutic/diagnostic systems and immune system targeting

Pollen is an excellent natural substance that plays an essential role in the reproduction of plants. In this review, we explain the structure, compositions, and characteristics of pollens. We consider pollen as a multifunctional tool that can be used in therapeutic/diagnostic systems. This microcapsule can be used in the forms of the hollow microcapsule, microgel, and composite, and also can be a tool for the synthesis of micro/nanostructures in various medical applications and used for the production of genetically modified plants that affect human health. In addition, we investigate the capability of this multifunctional tool in the immune system targeting that acts as an immunomodulator. In all applications and capabilities, we explain the potential of using nanostructures as parts of these systems and as auxiliary tools for promoting the applications of pollen. It is expected that soon, with the help of pollen-based therapeutic/diagnostic systems with the ability to immune system targeting, we will achieve effective and targeted therapeutic systems for the treatment of inflammatory and autoimmune diseases. In this paper, we suggest some ideas that may be a new step for future researches.

IgE and TGF-β Signaling: From Immune to Cardiac Remodeling

Cardiac remodeling is accompanied by cardiac hypertrophy, fibrosis, and dysfunction, eventually leading to heart failure (HF). However, the molecular mechanisms involved in cardiac remodeling are complicated, especially the association with immune. Immunoglobulin E (IgE) is a class of immunoglobulins involved in immune response to specific allergens. Recently, Zhao et al characterized a novel specific role of IgE and its high affinity receptor (FcεR1) in directly promoting pathological myocardial remodeling and cardiac dysfunction. Additionally, upon blocking IgE-FcεR1 signaling using FcεR1 genetic depletion or by administrating the anti-IgE monoclonal antibody omalizumab (Oma) in mice, they observed that cardiac hypertrophy and cardiac interstitial fibrosis induced by angiotensin II (Ang II) or transverse aortic constriction (TAC) were significantly suppressed. In contrast, IgE administration alone can aggravate pathological cardiac remodeling and dysfunction. RNA-seq and downstream analysis indicated that TGF-β was the common pathway and the most pivotal mediator in IgE-FcεR1-induced cardiac remodeling and dysfunction. Furthermore, the administration of a TGF-β inhibitor could ameliorate cardiac remodeling and improve cardiac function. Therefore, these findings suggest that IgE-FcεR1 maybe promising therapeutic targets for cardiac remodeling and provide an experimental basis for the use of omalizumab for HF patients combined with high serum IgE levels or allergic diseases.

Albumin/Globulin Ratio as Yin-Yang in Rheumatoid Arthritis and Its Correlation to Inflamm-Aging Cytokines

Purpose

Inflamm-aging is a novel-concept in rheumatoid arthritis (RA) with accelerating aging process. We try to find a correlation between serum albumin/globulin (A/G) ratio and clinical biochemical parameters, incidence of aging-related diseases (ARDs) as well as inflammaging-related molecules.

Patients and Methods

Healthy controls (HC) and RA patients were compared with their clinical biochemical parameters including albumin and globulin levels, A/G ratio, and levels of serum lipids. Incidence of ARDs in RA was compared with A/G ratio, having a cut off value of 1.2. Expression levels of leptin and Trf2 genes in PBMCs, and inflammatory factors like IL-1β, IL-6, IL-8 and TNF-ɑ between HC and RA patients were compared, and correlated with the A/G ratio.

Results

Compared to HC, RA patients had decreased levels of albumin, while globulin levels were found to be increased, which led to a significantly lower A/G ratio in RA patients. A/G ratio rather than ESR and CRP had significant correlation with dyslipidemia in RA patients. Patients with A/G <1.2 had a higher risk of ARDs than patients with A/G >1.2. The RR was 2.48 (95% CI: 1.79 to 3.64, p <0.0001). In addition, A/G ratio has positively correlated to leptin and Trf2 expression, while an inverse correlation was observed with the levels of inflamm-aging related cytokines like IL-6, IL-8 and TNF-ɑ.

Conclusion

A decreased A/G ratio in RA patients has significantly correlated with dyslipidemia and ARDs, as well as inflammaging- related adipokine and pro-inflammatory cytokines. Thus, A/G ratio could be a reliable marker for evaluating the inflammaging process during clinical management in ARDs.

Mycoplasma pneumoniae Seroprevalence and Total IgE Levels in Patients with Juvenile Idiopathic Arthritis

Background

Mycoplasma pneumoniae (M. pneumoniae) is implicated in several immune-mediated extrapulmonary manifestations, including reactive arthritis. Recently, increased total serum IgE were reported in children developing M. pneumoniae-related extrapulmonary diseases (MpEPDs). Here, we aimed at analyzing these aspects in children affected with rheumatic disorders and, in detail, Juvenile Idiopathic Arthritis (JIA).

Methods

M. pneumoniae serology (IgG and IgM) and total serum IgE were concomitantly analyzed in 139 pediatric patients diagnosed with: JIA (Group 1, n = 85), or any rheumatic disease other than JIA (Group 2, n = 27), or non-inflammatory endocrinological disorders (Group 3, n = 27).

Results

Overall, 19.4% M. pneumoniae seroprevalence was observed in this hospitalized pediatric population, without signicant differences among the three groups. No significant differences in total serum IgE levels were noted among these groups; however, a second analysis excluding children with very high (and clearly abnormal) IgE levels suggested that JIA patients and, in detail, those with oligopolyarticular forms may have higher serum IgE concentrations. This relative difference among groups in serum IgE level seems to be more pronounced in M. pneumoniae seropositive children.

Conclusions

M. pneumoniae infection should be actively sought in children developing immune-mediated diseases, including patients affected with JIA and, especially, in oligopolyarticular forms. There is some evidence that total serum IgE levels may tend to be increased in patients with oligopolyarticular JIA subtype and especially in those resulting as M. pneumoniae seropositive. However, further and focused research is needed to confirm these preliminary results and to clarify the relation between M. pneumoniae infection, atopic status, and immune-mediated arthritis.

Type 2 immunity-driven diseases: Towards a multidisciplinary approach

Asthma, atopic dermatitis and chronic rhinoconjunctivitis are highly heterogeneous. However, epidemiologic associations exist between phenotypic groups of patients. Atopic march is one such association but is not the only common point. Indeed, beyond such phenotypes, hallmarks of type 2 immunity have been found in these diseases involving immune dysregulation as well as environmental triggers and epithelial dysfunction. From the canonical Th2 cytokines (IL-4, IL-5, IL-13), new cellular and molecular actors arise, from the epithelium's alarmins to new innate immune cells. Their interactions are now better understood across the different environmental barriers, and slight differences appeared. In parallel, the development of type 2-targeting biotherapies not only raised hope to treat those diseases but also raised new questions regarding their true pathophysiological involvement. Here, we review the place of type 2 immunity in the different phenotypes of asthma, chronic rhinitis, chronic rhinosinusitis and atopic dermatitis, highlighting nuances between them. New hypotheses rising from the use of biotherapies will be discussed along with the uncertainties and unmet needs of this field.

The Association of Bullous Pemphigoid With Atopic Dermatitis and Allergic Rhinitis-A Population-Based Study

BACKGROUND

Although bullous pemphigoid (BP), atopic dermatitis (AD), and allergic rhinitis (AR) are associated with shared pathogenic mechanisms the epidemiological relationship between these conditions remains to be investigated.

OBJECTIVE

To evaluate the bidirectional association of BP with AD and AR.

METHODS

A population-based retrospective cohort study was performed comparing BP patients (n = 3924) with age-, sex-, and ethnicity-matched control subjects (n = 19,280), with respect to incident cases of AD and AR. A case-control design was additionally adopted to assess the odds of BP in individuals with a preexisting diagnosis of AD and AR.

RESULTS

The odds of BP was increased after a preexisting diagnosis of AD (fully adjusted odds ratio, 1.76; 95% confidence interval [CI], 1.44-2.15; P < 0.001) and AR (fully adjusted odds ratio, 1.13; 95% CI, 1.01-1.28; P = 0.047). Patients with BP were at an increased risk of subsequent AD (fully adjusted hazard ratio, 2.00; 95% CI, 1.60-2.51; P < 0.001) but not AR (fully adjusted hazard ratio, 1.00; 95% CI, 0.83-1.20; P = 0.997). Compared with other patients with BP, those with BP and comorbid AD and AR were more frequently managed by adjuvant drugs and long-term systemic and topical corticosteroids and had decreased all-cause mortality.

CONCLUSIONS

A history of AD and AR confers susceptibility to the development of BP. Awareness of this association may be of help for physicians managing patients with these diseases.

Chronic Urticaria: Advances in Understanding of the Disease and Clinical Management

Chronic urticaria (CU) is a common skin condition characterized by the recurrence of wheals, with or without angioedema, which lasts for at least 6 weeks. Owing to its pruritus and incurability, this disease adversely affects the patients' physical and mental health and diminishes the quality of life. CU is generally classified into two subtypes based on the relevance of eliciting factors: chronic spontaneous urticaria (CSU) and chronic inducible urticaria (CIndU), the latter of which is further divided into several subtypes. To improve the understanding and clinical management of this highly heterogeneous disorder, the EAACI/GA²LEN/EDF/WAO guideline was developed and published in 2018 based on evidence and expert consensus. The diagnostic and treatment algorithms proposed by the guideline have largely facilitated dermatologists in clinical practice. However, several questions remained unsolved and have been widely investigated in the recent years. First, a better understanding of the association between chronic urticaria and its potential underlying causes or eliciting factors such as autoimmunity, infections, coagulation aberrance, and vitamin D deficiency is warranted. This would lead to updates in the diagnostic and treatment procedures of different subtypes of chronic urticaria. Secondly, treatment for recalcitrant cases, especially those resistant to or intolerant of second-generation antihistamines and (or) omalizumab, calls for novel therapeutic measures or strategies. In the present review, we summarized recent advances in the understanding and management of both CSU and CIndU, with special emphasis on their underlying causes or eliciting factors, pathogenic mechanisms, potential targets for intervention, and advances in treatment strategies.

Presence of IgE Autoantibodies Against Eosinophil Peroxidase and Eosinophil Cationic Protein in Severe Chronic Spontaneous Urticaria and Atopic Dermatitis

Purpose

Eosinophils are frequently found in atopic dermatitis (AD) and chronic spontaneous urticaria (CSU) that release eosinophil peroxidase (EPX) and eosinophil cationic protein (ECP). Continuous exposure to these proteins could trigger an autoimmune response which may contribute to the pathogenesis and severity of skin inflammation. In this study, we investigate the immunoglobulin E (IgE) response against eosinophil proteins in CSU and AD.

Methods

We recruited patients with severe AD, severe CSU and healthy subjects to explore the presence of IgE autoantibodies and cross-reactivity against EPX, ECP and thyroid peroxidase (TPO). The potential cross-reactive epitopes among the peroxidase family were determined using in silico tools.

Results

The frequencies of anti-EPX IgE (28.8%) and anti-ECP IgE (26.6%) were higher in the AD group, and anti-TPO IgE was higher in the CSU group (27.2%). In the CSU group, there was a correlation between the anti-EPX IgE and anti-TPO IgE levels (r = 0.542, P < 0.001); TPO inhibited 42% of IgE binding to EPX, while EPX inhibited 59% of IgE binding to TPO, suggesting a cross-reactivity with EPX as a primary sensitizer. There was greater inhibition when we used a pool of sera CSU and AD, TPO inhibited 52% of IgE binding to EPX, while EPX inhibited 78% of IgE binding to TPO. In silico analysis showed a possible shared epitope in the peroxidase protein family.

Conclusions

IgE against eosinophil proteins may contribute to chronic inflammation in patients with AD and CSU. Cross-reactivity between EPX and TPO could explain thyroid problems in CSU patients.

Is There a Clinical Significance of Very Low Serum Immunoglobulin E Level?

PURPOSE

High serum immunoglobulin (Ig) E levels are associated with allergies, parasitic infections, and some immune deficiencies; however, the potential effects and clinical implications of low IgE levels on the human immune system are not well-known. This study aims to determine the disorders accompanying very low IgE levels in children and adults.

METHODS

The patients whose IgE levels were determined between January 2015 and September 2020 were analyzed, and the patients with an IgE level < 2 IU/mL were included in this study. Demographic data, immunoglobulin levels, autoantibody results, and the diagnoses of the patients were noted from the electronic recording system of the hospital.

RESULT

The IgE levels were measured in 34,809 patients (21,875 children, 12,934 adults), and 130 patients had IgE levels < 2 IU/mL. Fifty-seven patients were children (0.26%); 73 were adults (0.56%). There was a malignant disease in 34 (9 of them children) (26%), autoimmune diseases in 20 (3 of them children) (15.4%), and immunodeficiency in 17 (14 of them children) (13.1%) of the patients. The most common reasons were other diseases, immunodeficiency and malignancy in children, and malignancy, autoimmune disorders, and other diseases in the adults, in rank order. The IgE level did not show any correlation with the levels of other immunoglobulins.

CONCLUSION

Although rare, a low IgE level has been shown to accompany malignancies, autoimmune disorders, and immune deficiencies. Patients with very low IgE levels should be carefully monitored for systemic disorders.