IgE directly affects eosinophil migration in chronic rhinosinusitis with nasal polyps through CCR3 and predicts the efficacy of omalizumab.

BACKGROUND: Whether IgE affects eosinophil migration in chronic rhinosinusitis with nasal polyps (CRSwNP) remains largely unclear. Moreover, our understanding of local IgE, eosinophils, and omalizumab efficacy in CRSwNP remains limited. OBJECTIVE: We investigated whether IgE acts directly on eosinophils and determined its role in omalizumab therapy. METHODS: Eosinophils and their surface receptors were detected by hematoxylin and eosin staining and flow cytometry. IgE and its receptors, eosinophil peroxidase (EPX), eosinophilic cationic protein, and CCR3 were detected by immunohistochemistry and immunofluorescence. Functional analyses were performed on blood eosinophils and polyp tissues. Logistic regression was performed to screen for risk factors. Receiver operating characteristic curve was generated to evaluate the accuracy. RESULTS: Both FcεRI and CD23 were expressed on eosinophils. The expression of FcεRI and CD23 on eosinophil in nasal polyp tissue was higher than in peripheral blood (both P < .001). IgE and EPX colocalized in CRSwNP. IgE directly promoted eosinophil migration by upregulating CCR3 in CRSwNP but not in healthy controls. Omalizumab and lumiliximab were found to be effective in restraining this migration, indicating CD23 was involved in IgE-induced eosinophil migration. Both IgE+ and EPX+ cells were significantly reduced after omalizumab treatment in those who experienced response (IgE+ cells, P = .001; EPX+ cells, P = .016) but not in those with no response (IgE+ cells, P = .060; EPX+ cells, P = .151). Baseline IgE+ cell levels were higher in those with response compared to those without response (P = .024). The baseline local IgE+ cell count predicted omalizumab efficacy with an accuracy of 0.811. CONCLUSIONS: IgE directly promotes eosinophil migration, and baseline local IgE+ cell counts are predictive of omalizumab efficacy in CRSwNP.

Combined analytical assays for the characterization of drugs binding to human IgE: Applicability to omalizumab-bearing biosimilar candidates assessment.

Analytical and functional comparison is key for substantiating the level of convergence (essential sameness) or divergence between versions or variants of a given biological medicine. Accordingly, an overlapping biological activity between products meant to be equal probably reflects a highly similar structure and anticipates a comparable pharmacodynamic behavior. We developed an orthogonal approach to compare the human IgE binding features of different lots and versions of Xolair® (omalizumab), an anti-human IgE monoclonal antibody. The IgE binding affinity and kinetics were measured by surface plasmon resonance. Ability to prevent mast cell activity was assessed in vitro and in vivo in mast cell-based models. The variability of monoclonal antibodies with identical amino acid sequences produced either in Chinese hamster ovarian cells or in human HEK293 cells, was compared. Monoclonal antibodies from the two sources exhibited slightly different human IgE binding and neutralizing features. A known variant exhibiting a three amino acid replacement in the Fab region had lower IgE binding affinity than the original omalizumab. The lower binding affinity translated into reduced IgE neutralizing capacity and, in turn, a difference in the ability to prevent mast cell activation in vitro and in vivo. The proposed set of analytical and functional assays was sensitive enough to detect Fab-linked differences between anti-IgE antibody versions exhibiting an identical aminoacid sequence. In addition to add value to the comparative assessment of biosimilar candidates bearing omalizumab, these methods can aid pre-assessments of new anti-IgE agents that aim to improve therapeutic performance.

Population-Based Pharmacodynamic Modeling of Omalizumab in Pediatric Patients with Moderate to Severe Persistent Inadequately Controlled Allergic Asthma.

Omalizumab is the first approved anti-immunoglobulin E (IgE) agent for the treatment of moderate to severe persistent inadequately controlled allergic asthma in adults and adolescents (≥ 12 years old). In 2016, it was approved in pediatric patients (6-11 years old). The objective of this study was to quantitatively characterize the relationship between serum free IgE and pulmonary function (as measured by forced expiratory volume in 1 s [FEV1]) in pediatrics using a population-based pharmacodynamic model. Data collected during the steroid-stable period (first 24 weeks) of an omalizumab trial with pediatric asthma patients (Study IA05) were used to build the pediatric IgE-FEV1 model. The previously developed population IgE-FEV1 model in adults/adolescents was adapted to characterize the FEV1 and IgE relationship in pediatrics with different magnitude and onset of response. The pediatric IgE-FEV1 model adequately characterized the IgE-FEV1 relationship in pediatrics, particularly at the extremes of the observed body weights (i.e., ≤ 30 kg) and IgE values at screening (i.e., > 700 IU/mL). The estimated sigmoidal free IgE-FEV1 curves were similar in shape and maximum effect, but the estimated free IgE concentration leading to 50% maximum effect (IC50) in pediatric patients (39.4, 95% confidence interval [CI] 24.3-63.9 ng/mL) was higher than estimated in adults (19.8, 95% CI 15.1-24.5 ng/mL). The model further confirmed that the current omalizumab dosing rationale based on the mean target free IgE level of 25 ng/ml was appropriate. The pediatric model can be used to predict population FEV1 response for omalizumab when combined with an omalizumab pharmacokinetic-IgE model.

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.

[Analysis of predictors of response to anti-IgE therapy in patients with severe atopic bronchial asthma in real clinical practice].

INTRODUCTION: Guidelines on Biological Therapy for Bronchial Asthma of the European Academy of Allergy and Clinical Immunology (EAACI) identified a number of controversial issues for additional outcome analysis using randomized clinical trials and data from routine clinical practice. In particular, there is unmet need to clarify algorithms for prescribing biologicals using predictors of response and its timing, taking into account risk factors and multimorbidity. Omalizumab is a recombinant humanized monoclonal anti-IgE antibody of IgG1 class used for the treatment of severe refractory atopic bronchial asthma (BA) and a variety of IgE-mediated diseases. Among biological agents, this "pioneer molecule" has the greatest experience in the "allergology and immunology" profile. Detailed description of the "nonresponders" portraits will allow to perform the therapy response assessment on time and facilitate rational planning of individual therapy, which is a prerequisite for biologicals era. Using only routine methods, it is possible to perform initial and dynamic screening to phenotype a heterogeneous cohort of patients with severe asthma and chose the optimal strategy. AIM: To identify predictors of nonresponse to omalizumab anti-IgE therapy in patients with severe atopic BA and to establish optimal timing of efficacy assessment using retrospective analysis of data from the Biologic Therapy Registry of Allergology and Immunology in routine clinical practice. MATERIALS AND METHODS: A retrospective single-center registry study was conducted at the Allergy and Immunology Reference Center from June 2017 to August 2021. 135 patients with severe BA, with confirmed perennial sensitization, who received omalizumab according to the recommendations of the current version of GINA, were selected from the clinical and dynamic observational system (registry). Dosing regimen and administration frequency of omalizumab were determined in accordance with the instructions for the drug. Assessment of therapy efficacy was performed at the time point 4, 6 and 12 months. Patients were subgrouped into "responders" and "non-responders" according to the following criteria: ACT score less than 19 and/or difference between initial ACT score in dynamics less than 3 points; forced expiratory volume in the first second less than 80%; combination of these two criteria. Nonparametric methods of descriptive statistics were used in data processing: median, interquartile range. Differences were considered significant at p0.05. MannWhitney U-test, KruskalWallis one-way analysis of variance, and Fisher's 2 test were used to compare quantitative characteristics. RESULTS: Heterogeneous subgroups of patients differing in reaching the criteria of "non-responders" to treatment were identified; the informativity of modifiable and unmodifiable factors differed at time-points of dynamic observation. In the differential analysis, two profiles of "nonresponders" were defined in combination with the most significant predictors of "nonrsponse" to omalizumab. According to the data obtained, one of the clinical phenotypes, namely the combination of severe asthma with the Samters triad, corresponded to the characteristics of the patient "nonresponders": age of onset is about 30 years, females, severe exacerbations of BA while taking non-steroidal anti-inflammatory drugs, accompanied with high levels of eosinophilia. CONCLUSION: The data obtained illustrates the hypothesis of pathogenetic heterogeneity of severe BA with the phenomenon of overlapping phenotypes and can serve as an additional orienteer for creating the individual plan of anti-IgE therapy in real clinical practice.

IgE-neutralizing UB-221 mAb, distinct from omalizumab and ligelizumab, exhibits CD23-mediated IgE downregulation and relieves urticaria symptoms.

Over the last 2 decades, omalizumab is the only anti-IgE antibody that has been approved for asthma and chronic spontaneous urticaria (CSU). Ligelizumab, a higher-affinity anti-IgE mAb and the only rival viable candidate in late-stage clinical trials, showed anti-CSU efficacy superior to that of omalizumab in phase IIb but not in phase III. This report features the antigenic-functional characteristics of UB-221, an anti-IgE mAb of a newer class that is distinct from omalizumab and ligelizumab. UB-221, in free form, bound abundantly to CD23-occupied IgE and, in oligomeric mAb-IgE complex forms, freely engaged CD23, while ligelizumab reacted limitedly and omalizumab stayed inert toward CD23; these observations are consistent with UB-221 outperforming ligelizumab and omalizumab in CD23-mediated downregulation of IgE production. UB-221 bound IgE with a strong affinity to prevent FcԑRI-mediated basophil activation and degranulation, exhibiting superior IgE-neutralizing activity to that of omalizumab. UB-221 and ligelizumab bound cellular IgE and effectively neutralized IgE in sera of patients with atopic dermatitis with equal strength, while omalizumab lagged behind. A single UB-221 dose administered to cynomolgus macaques and human IgE (ε, κ)-knockin mice could induce rapid, pronounced serum-IgE reduction. A single UB-221 dose administered to patients with CSU in a first-in-human trial exhibited durable disease symptom relief in parallel with a rapid reduction in serum free-IgE level.

Impact of body mass index on omalizumab response in adults with moderate-to-severe allergic asthma.

BACKGROUND: Effectiveness of asthma treatment, including biologics, may be different in patients with higher body mass index (BMI). OBJECTIVE: To evaluate response to omalizumab (dosed by serum immunoglobulin E level and weight) by BMI category. METHODS: Pooled data from 2 randomized, double-blind, placebo-controlled studies of adults with moderate-to-severe allergic asthma were analyzed by BMI category (<25 kg/m2 [normal or underweight], n = 397; 25 to <30 kg/m2 [overweight], n = 330; ≥ 30 kg/m2 [obese], n = 268). Placebo-adjusted exacerbation rate reductions were evaluated by Poisson regression modeling. Changes from baseline in forced expiratory volume in 1 second, beclomethasone dipropionate (BDP) dose, Total Asthma Symptom Score, and Asthma Quality of Life Questionnaire were evaluated by analysis of covariance. RESULTS: Greater placebo-adjusted exacerbation rate reductions (95% confidence interval) were observed with increasing BMI (normal or underweight, -37.4% [-69.0% to 26.8%]; overweight, -52.7% [-78.4% to 3.7%]; obese, -71.9% [-86.9% to -39.5%]). There were no differences in forced expiratory volume in 1 second improvement between BMI categories at week 16 (normal or underweight, 76.2 [5.3-147.1] mL; overweight, 98.1 [13.9-182.4] mL; obese, 69.1 [-18.9 to 157.2] mL). No differences in BDP dose reduction (µg) were noted between BMI categories (normal or underweight, 23.0 [15.7-30.3]; overweight, 22.5 [13.5-31.5]; obese, 16.6 [5.8-27.3]). Fewer patients in the higher BMI categories eliminated BDP use. There were trends for smaller improvements with higher BMI in Total Asthma Symptom Score (normal/underweight, -0.52 [-0.82 to -0.22]; overweight, -0.50 [-0.80 to -0.20]; obese, -0.39 [-0.77 to 0.00]) and Asthma Quality of Life Questionnaire (normal or underweight, 0.34 [0.16-0.52]; overweight, 0.34 [0.13-0.55]; obese, 0.15 [-0.08 to 0.39]). CONCLUSION: Omalizumab provides benefit to patients with moderate-to-severe allergic asthma, regardless of BMI. TRIAL REGISTRATION: Studies 008/009 were conducted before clinical trial registration was required, and therefore clinical trial registration numbers are not available.

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.

Directed evolution of and structural insights into antibody-mediated disruption of a stable receptor-ligand complex.

Antibody drugs exert therapeutic effects via a range of mechanisms, including competitive inhibition, allosteric modulation, and immune effector mechanisms. Facilitated dissociation is an additional mechanism where antibody-mediated "disruption" of stable high-affinity macromolecular complexes can potentially enhance therapeutic efficacy. However, this mechanism is not well understood or utilized therapeutically. Here, we investigate and engineer the weak disruptive activity of an existing therapeutic antibody, omalizumab, which targets IgE antibodies to block the allergic response. We develop a yeast display approach to select for and engineer antibody disruptive efficiency and generate potent omalizumab variants that dissociate receptor-bound IgE. We determine a low resolution cryo-EM structure of a transient disruption intermediate containing the IgE-Fc, its partially dissociated receptor and an antibody inhibitor. Our results provide a conceptual framework for engineering disruptive inhibitors for other targets, insights into the failure in clinical trials of the previous high affinity omalizumab HAE variant and anti-IgE antibodies that safely and rapidly disarm allergic effector cells.

Chronic Rhinosinusitis with Nasal Polyps: Targeting IgE with Anti-IgE Omalizumab Therapy.

Chronic rhinosinusitis with nasal polyps (CRSwNP) is a complex, clinically heterogeneous and persistent inflammatory disorder of the upper airway. Detailed mechanistic insights into disease pathogenesis are lacking, but it is now accepted that local tissue IgE driven T2-high inflammatory pathways are critical to disease. The recent CRSwNP Phase 3 POLYP1 and POLYP2 replicate studies of blocking IgE with omalizumab confirmed rapid improvements in all clinical parameters of sinonasal disease, confirming a pivotal role for IgE driven inflammatory pathways in CRSwNP. This review summarises the biology of IgE in relation to CRSwNP. Insight into how IgE may drive CRSwNP is evaluated in the context of clinical improvements seen with omalizumab. The need for further studies using a broader patient and biomarker specific groups to aid more precise drug-patient selection alongside more detailed mechanistic studies of omalizumab in CRSwNP is highlighted.

An Omalizumab Biobetter Antibody With Improved Stability and Efficacy for the Treatment of Allergic Diseases.

The critical role of IgE in allergic diseases is well-documented and clinically proven. Omalizumab, a humanized anti-IgE antibody, was the first approved antibody for the treatment of allergic diseases. Nevertheless, omalizumab still has some limitations, such as product instability and dosage restriction in clinical application. In this study, we attempted to develop an omalizumab biobetter antibody with the potential to overcome its limitations. We removed two aspartic acid isomerization hotspots in CDRs of omalizumab to improve antibody candidate's stability. Meanwhile, several murine amino acids in the framework region of omalizumab were replaced with human source to reduce the potential immunogenicity. Yeast display technology was then applied to screen antibody candidates with high binding affinity to IgE. Moreover, YTE mutation in Fc fragment was introduced into the candidates for extending their serum half-life. A lead candidate, AB1904Am15, was screened out, which showed desired biophysical properties and improved stability, high binding affinity and elevated potency in vitro, prolonged half-life in human FcRn transgenic mouse, and enhanced in vivo efficacy in cynomolgus monkey asthma model. Overall, our study developed a biobetter antibody of omalizumab, AB1904Am15, which has the potential to show improved clinical benefit in the treatment of allergic diseases.

Effects of omalizumab on basophils: Potential biomarkers in asthma and chronic spontaneous urticaria.

Omalizumab is an anti-IgE humanized monoclonal antibody approved for the treatment of severe asthma and chronic spontaneous urticaria. Omalizumab binds free serum IgE and antagonizes its interaction with FcεRI, which is considered the main pharmacodynamic mechanism responsible for the clinical response to the treatment. The reduction of IgE serum concentration down-regulates the cellular expression of FcεRI on basophils. However, the biological events occurring on basophils during the therapy with omalizumab are multiple and complex. Here we review the current evidence regarding the specific biological effects of omalizumab on basophils in patients with asthma and chronic spontaneous urticaria. In addition to the modulation of IgE receptors, omalizumab may affect basophils homeostasis, intra-cellular signaling, cellular responsiveness/activation and cytokine release. These effects may be partially responsible for the clinical success of omalizumab and potentially provide useful biological markers for future assessment of the clinical response to the treatment. However, further investigation is required to better elucidate the role of basophils during the treatment with omalizumab.

Biologics for the Treatment of Food Allergies.

Food allergy is increasingly prevalent and poses a life-threatening risk to those afflicted. The health care costs associated with food allergies are also increasing. Current and emerging treatments for food allergies aim at protecting against reactions caused by accidental ingestion and increasing the food allergen reaction threshold, although this protection is often temporary. In the future, ideal biologic therapies would target key mediators of the type II immune pathway, essential in development of the atopic march to prevent development of food allergies. Biologics offering long-term protection against allergic reactions to food are needed, and several agents are already in development.

Biologics for Atopic Dermatitis.

Atopic dermatitis (AD) is a common chronic inflammatory skin disease that has become a global health problem. The pathophysiology of AD includes both skin barrier and immune abnormalities, with type 2 immune deviation central to several clinical phenotypes and underlying endotypes. Recognition of the persistent nature and systemic aspects of AD provides a rationale for treatment with a biologic. Dupilumab has been approved for patients 6 years of age and older with moderate to severe AD. Monoclonal antibodies are in phase 3 trials and may become part of a precision medicine approach to AD.

Biologics and Allergy Immunotherapy in the Treatment of Allergic Diseases.

Allergic diseases represent some of the most chronic and costly chronic conditions. Medical management may require long-term pharmacotherapy, which is often associated with poor adherence. Although medications provide symptomatic control, they do not modify the allergic disease. Patients may prefer disease-modifying treatments that provide lasting benefits after discontinuation. To date, allergy immunotherapy is the only proved disease modification therapy associated with lasting benefits after discontinuation. However, allergy immunotherapy safety and efficacy has only been established in allergic rhinitis, mild to moderate asthma, and some patients with atopic dermatitis.

Effect of omalizumab use on glucose homeostasis in non-diabetic patients with chronic urticaria.

PURPOSE: In some diabetic patients receiving omalizumab therapy, blood glucose regulation is impaired. However, the effect of omalizumab on glucose homeostasis in non-diabetic patients remains unknown. METHODS: The patients were given subcutaneous omalizumab at a dose of 300 mg every four weeks for the treatment of chronic urticaria in this study. Fasting blood glucose, fasting plasma insulin, total cholesterol, triglyceride, and high-density (HDL) and low-density lipoprotein (LDL) were studied before and at the 12th week of treatment. The homeostatic model assessment for insulin resistance (HOMA-IR) was used to determine insulin resistance. RESULTS: Forty of the 45 patients included in the study completed 12 weeks of treatment. While fasting blood glucoses (p = 0.011) and HOMA-IR values (p = 0.027) were significantly increased in the 12th week, the increase in fasting insulin level was not significant (p = 0.07). After treatment, 10 patients developed impaired fasting glucose and 13 developed insulin resistance. CONCLUSION: The increase in blood glucose levels may be associated with the paradoxically increase of histamine levels in the blood by omalizumab. If this increase cannot be balanced with insulin, patients may develop impaired glucose tolerance and insulin resistance. Therefore, we suggest that patients using omalizumab should be followed up for glucose homeostasis and insulin resistance.

Targeted Therapy for Chronic Spontaneous Urticaria: Rationale and Recent Progress.

Chronic spontaneous urticaria (CSU) is characterized by the presence of wheals, angioedema, or both for at least 6 weeks. It may persist for a long time-up to 50% of the patients have been reported to be symptomatic 5 years after the onset. Some patients can suffer more than one episode of CSU during their lifetime. Considering the recurrences, disabling symptoms, and significant impact on quality of life, proper and effective treatment of CSU is critical. The use of antihistamines (AHs) is still the mainstay of treatment. However, given the low rates of response to AHs (38.6% and 63.2% to standard doses and higher doses, respectively), the complete control of symptoms seems difficult to attain. The use of omalizumab for CSU has been a major breakthrough in the care of patients with CSU. However, the partial response and lack of response to omalizumab in a subgroup of patients, as high as 70% in some studies, make the development of alternative treatments desirable. Ever-increasing knowledge on the pathogenesis is making new target molecules available and enabling drug development for CSU. In addition to drug repurposing as in anti-IL-4/13, IL-5, and IL-17 antibodies, novel targeted therapy options such as ligelizumab and Bruton's tyrosine kinase inhibitors are currently undergoing clinical trials and will be available in the near future. This article reviews the current challenges in the treatment of CSU, the pathogenesis and potential target molecules, and the rationale for novel treatments and their rapidly developing status.

What the physicians should know about mast cells, dendritic cells, urticaria, and omalizumab during COVID-19 or asymptomatic infections due to SARS-CoV-2?

Coronavirus disease (COVID-19) pandemic presents several dermatological manifestations described in the present indexed literature, with around 700 cases reported until May 2020, some described as urticaria or urticarial rashes. Urticaria is constituted by evanescent erythematous-edematous lesions (wheals and flare), which does not persist in the same site for more than 24 to 48 hours and appears in other topographic localization, resolving without residual hyper pigmentation. During the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, some cytokines are synthesized, including Interferon (IFN) type I, TNF-α, and chemokines which may induce mast cells (MCs) and basophils degranulation by mechanisms similar to the autoinflammatory monogenic or polygenic diseases. In this article, we discuss the spectrum of the urticaria and urticarial-like lesions in the COVID-19's era, besides other aspects related to innate and adaptative immune response to viral infections, interactions between dermal dendritic cells and MCs, and degranulation of MCs by different stimuli. Plasmacytoid dendritic cells share, in allergic patients, expression of the high-affinity IgE receptors on cell membranes and demonstrated a low pattern of type I IFN secretion in viral infections. We discuss the previous descriptions of the effects of omalizumab, a monoclonal antibody directed to IgE and high-affinity IgE receptors, to improve the IFN responses and enhance their antiviral effects.

Promising Use of the New Biologics in the Management of Drug-Induced Hypersensitivity Reactions: Preliminary Approaches.

Biologics are an innovative class of drugs that can selectively influence immunological responses at a cellular level. Although their use is usually restricted to some specific diseases, such as autoimmune pathologies and tumors, their "off-label" administration has increased widely in the last years. Drug treatment may induce hypersensitivity reactions which currently lack any gold standard therapy but maybe a future field of application for biologics. Agents like anti-IgE (Omalizumab) and Tumor Necrosis Factor-α inhibitors might be used in immediate-type and cell-mediated hypersensitivity caused by medications, respectively, and the first trials in that direction are being reported in the literature. In fact, the refined immunological mechanisms involved in the pathogenesis of drug hypersensitivity might respond successfully to this new class of drugs.