Elevated Prostaglandin E2 Synthesis Is Associated with Clinical and Radiological Disease Severity in Cystic Fibrosis.

Background: Previous studies found high but very variable levels of tetranor-PGEM and PGDM (urine metabolites of prostaglandin (PG) E2 and PGD2, respectively) in persons with cystic fibrosis (pwCF). This study aims to assess the role of cyclooxygenase COX-1 and COX-2 genetic polymorphisms in PG production and of PG metabolites as potential markers of symptoms' severity and imaging findings. Methods: A total of 30 healthy subjects and 103 pwCF were included in this study. Clinical and radiological CF severity was evaluated using clinical scoring methods and chest computed tomography (CT), respectively. Urine metabolites were measured using liquid chromatography/tandem mass spectrometry. Variants in the COX-1 gene (PTGS1 639 C>A, PTGS1 762+14delA and COX-2 gene: PTGS2-899G>C (-765G>C) and PTGS2 (8473T>C) were also analyzed. Results: PGE-M and PGD-M urine concentrations were significantly higher in pwCF than in controls. There were also statistically significant differences between clinically mild and moderate disease and severe disease. Patients with bronchiectasis and/or air trapping had higher PGE-M levels than patients without these complications. The four polymorphisms did not associate with clinical severity, air trapping, bronchiectasis, or urinary PG levels. Conclusions: These results suggest that urinary PG level testing can be used as a biomarker of CF severity. COX genetic polymorphisms are not involved in the variability of PG production.

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.

Chronic rhinosinusitis with nasal polyps and allergic rhinitis as different multimorbid treatable traits in asthma.

Background: Respiratory multimorbidities are linked to asthma, such as allergic rhinitis (AR) with early allergic asthma and chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) with late nonallergic asthma. Objective: Our aim was to investigate the association of asthma severity and control with specific upper airway phenotypes. Method: Patients with asthma were prospectively recruited from 23 pulmonology and ear, nose, and throat clinics. Asthma severity and control, as well as upper airway comorbidities (AR and non-AR [NAR], CRSwNP, and CRS without nasal polyps [CRSsNP]) were assessed according to international consensus guidelines definitions. Results: A total of 492 asthmatic patients were included. Half of the asthmatic patients (49.6%) had associated rhinitis (37.0% had AR and 12.6% had NAR) and 36.2% had CRS (16.7% had CRSsNP and 19.5% had CRSwNP), whereas 14.2% had no sinonasal symptoms. Most cases of AR (78%) and NAR (84%) were present in patients with mild-to-moderate asthma, whereas CRSwNP was more frequent in patients with severe asthma (35% [P < .001]), mainly nonatopic asthma (44% [P < .001]). Patients with severe asthma with CRSwNP had worse asthma control, which was correlated (r = 0.249 [P = .034]) with sinus occupancy. Multiple logistic regression analysis showed that late-onset asthma, intolerance of aspirin and/or nonsteroidal anti-inflammatory drugs, and CRSwNP were independently associated with severe asthma. Conclusion: Severe asthma is associated with CRSwNP, with sinus occupancy affecting asthma control. This study has identified 2 main different upper airway treatable traits, AR and CRSwNP, which need further evaluation to improve management and control of patients with asthma.

Effect of Obesity on the Expression of Genes Associated with Severe Asthma-A Pilot Study.

Asthma is a complex condition resulting from the interaction of genes and environment. Obesity is a risk factor to develop asthma and contributes to poor response to asthma therapy and severity. The aim of the study was to evaluate the effect of obesity on the expression levels of genes previously associated with severe asthma. Three groups of subjects were studied: non-obese asthmatics (NOA), obese asthma patients (OA), and non-asthmatic obese subjects (O). Previously reported overexpressed (IL-10, MSR1, PHLDA1, SERPINB2, and CD86) and underexpressed genes (CHI3L1, CPA3, IL-8, and PI3) in severe asthma were analyzed by RT-qPCR in peripheral blood mononuclear cells (PBMCs). In the overexpressed genes, obesity significantly decreased the expression of MSR1 and PHLDA1 and had no effects on CD86, IL-10, and SERPINB2. In underexpressed genes, obesity did not affect PI3, CHI3L1, and IL-8 and significantly reduced CPA3 expression. The results of this study show that obesity should be included among the known factors that can contribute toward modifying the expression of genes associated with asthma and, in particular, severe asthma.

Disposition of Work-Related Asthma in a Spanish Asthma Cohort: Comparison of Asthma Severity Between Employed and Retired Workers.

BACKGROUND: Exposure to certain agents in the workplace can trigger occupational asthma or work-exacerbated asthma, both of which come under the heading of work-related asthma (WRA). Understanding the burden that WRA represents can help in the management of these patients. OBJECTIVE: To assess the influence of occupation on asthma in real life and analyze the characteristics of patients with WRA included in an asthma cohort. METHODS: This was a prospective multicenter study of a cohort of consecutive patients with asthma. A standardized clinical history was completed. Patients were classified as having WRA or non-WRA. All patients underwent respiratory function tests, FeNO test, and methacholine challenge (methacholine concentration that causes a 20% drop in FEV1) at the beginning of the study. They were classified into two groups, depending on their employment status: employed (group 1) or unemployed (group 2). RESULTS: Of the 480 patients included in the cohort, 82 (17%) received the diagnosis of WRA. Fifty-seven patients (70%) were still working. Mean age (SD) was 46 (10.69) years in group 1 and 57 (9.91) years in group 2 (P < .0001). Significant differences were observed in adherence to treatment (64.9% in group 1 vs 88% in group 2; P = .0354) and in severe asthma exacerbations (35.7% in group 1 vs 0% in group 2; P = .0172). No significant differences were observed in the rest of the variables analyzed. CONCLUSIONS: The burden of WRA in specialized asthma units is not negligible. The absence of differences in the severity of asthma, the treatment administered, alterations in lung function, and the number of exacerbations in those working versus not working may support the idea that advice regarding changing jobs should be customized for individual patients.

Identification of Asthma Phenotypes in the Spanish MEGA Cohort Study Using Cluster Analysis.

INTRODUCTION: The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes. METHODS: We performed a multicentre prospective cohort study, including adult patients with asthma (N=512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma). A standardised clinical history was completed for each patient. Cluster analysis was performed using the kernel k-groups algorithm. RESULTS: Four clusters were identified. Cluster 1 (31.5% of subjects) includes adult-onset atopic patients with better lung function, lower BMI, good asthma control, low ICS dose, and few exacerbations. Cluster 2 (23.6%) is made of adolescent-onset atopic asthma patients with normal lung function, but low adherence to treatment (59% well-controlled) and smokers (48%). Cluster 3 (17.1%) includes adult-onset patients, mostly severe non-atopic, with overweight, the worse lung function and asthma control, and receiving combination of treatments. Cluster 4 (26.7%) consists of the elderly-onset patients, mostly female, atopic (64%), with high BMI and normal lung function, prevalence of smokers and comorbidities. CONCLUSION: We defined four phenotypes of asthma using unsupervised cluster analysis. These clusters are clinically relevant and differ from each other as regards FEV1, age of onset, age, BMI, atopy, asthma severity, exacerbations, control, social class, smoking and nasal polyps.

Mechanisms by which dupilumab normalizes eicosanoid metabolism and restores aspirin-tolerance in AERD: A hypothesis.

Aspirin-exacerbated respiratory disease (AERD) is associated with overproduction of proinflammatory cysteinyl leukotrienes (CysLTs), defective generation of anti-inflammatory prostaglandin E2 (PGE2), and reduced expression of the EP2 receptor for PGE2. Reduced PGE2 synthesis results from the downregulation of inducible COX-2. Because PGE2 signaling via EP2 inhibits the 5-lipoxygenase/leukotriene C4 synthase-dependent pathway, the deficient levels of both PGE2 and EP2 likely contribute to the excessive baseline production of cysteinyl leukotrienes in patients with AERD compared with in patients with aspirin-tolerant asthma. The COX-2 pathway is regulated by an autocrine metabolic loop involving IL-1ß, IL-1 receptor type I, EP2, COX-2, membrane-bound PGE2 prostaglandin E2 synthase-1, and PGE2. Previous studies reported that this metabolic loop is dysregulated in patients with AERD. When the downexpressed EP2 receptor is normalized, the entire loop returns to its normal function. Cotreatment of airway cells from healthy subjects with IL-4 and IFN-γ induces alterations in the metabolic loop similar to those seen in patients with AERD. In these patients, IL-4, which is produced in excess in airways of patients with AERD, likely contributes to the alteration of normal functioning of the autocrine metabolic loop involving IL-1ß, IL-1 receptor type I, EP2, COX-2, membrane-bound PGE2 prostaglandin E2 synthase-1, and PGE2. We hypothesized that by blocking IL-4 action, dupilumab normalizes EP2 expression and restores the normal functioning of the COX-2 pathway autocrine metabolic loop, thereby normalizing the synthesis of PGE2 and restoring aspirin tolerance.

Skin Manifestations in Patients with Selective Immunoglobulin E Deficiency.

Selective immunoglobulin E deficiency (SIgED) is still an unrecognised primary immunodeficiency despite several observations supporting its existence. This study aimed to describe the skin manifestations associated with SIgED. We retrospectively assessed medical records of patients with SIgED, the diagnosis being based on serum IgE levels ≤2 Uk/L associated with normal serum levels of immunoglobulins G, M, and A. A total of 25 patients (24 female) with SIgED were included in the study. Eleven patients (44%) presented chronic spontaneous urticaria (CSU), five (20%) angioedema always associated with CSU, five erythema (20%), and six eczema (24%). Other, less frequent manifestations were lichen planus, anaphylactoid purpura, thrombocytopenic purpura, bullous pemphigoid, bullous pyoderma gangrenosum, and atypical skin lymphoproliferative infiltrate associated with reactive lymphadenopathy, chronic cholestasis, arthritis, and fibrosing mediastinitis. Fifteen patients (60%) had different types of associated autoimmune diseases, Hashimoto's thyroiditis being the most frequent (n = 5, 20%), followed by arthritis (n = 4, 16%), autoimmune hepatitis, neutropenia, vitiligo, and Sjögren's syndrome (n = 2, 8% each). Five malignancies were diagnosed in four patients (16%). An ultralow IgE serum level may be the only biomarker that reveals the presence of a dysregulated immune system in patients with a broad spectrum of skin manifestations.

Prevalence and associated factors for asthma in adults in Quito: a cross-sectional study.

Background: Although several epidemiological studies of asthma have been carried out in Ecuador in the last two decades, none of these has estimated the prevalence of asthma in adult populations. Objective: To estimate the prevalence of asthma symptoms in adults in the city of Quito and to identify possible associated factors. Methods: A cross-sectional study was conducted on subjects older than 18 years residing in the Metropolitan District of Quito. The Global Asthma Network (GAN) questionnaire was applied to collect information on asthma symptoms and sociodemographic and lifestyle data. Bivariate and multivariate analyses with logistic regression were used to identify asthma-related factors. Results: 2,476 subjects answered the questionnaire (80.9% women, mean age 40 years). The prevalence of wheezing in the last 12 months, asthma ever, and asthma diagnosed by a doctor were 6.3%, 1.9% and 1.6%, respectively. The prevalence of rhinitis ever and eczema ever was 13.7% and 5.5%. The presence of mould at home (OR: 2.13; 95% CI: 1.48 -3.06; p <0.001), cat at home (OR: 1.06; 95% CI: 1.06 -2.13; p <0.022) and rhinitis at some time (OR: 3.65; 95% CI: 2.53 - 5.29; p <0.022) were associated with the presence of wheezing in the last 12 months. Conclusions: Our study shows that, compared to other cities in Latin America, the prevalence of asthma in adults in Quito is relatively low. Along with the presence of rhinitis, factors related to housing quality are closely linked to the occurrence of asthma in adult populations.

Antecedentes: Aunque en el Ecuador se han realizado varios estudios epidemiológicos de asma en las dos últimas décadas, ninguno de estos ha estimado la prevalencia de asma en poblaciones adultas. Objetivo: Estimar la prevalencia de síntomas de asma en adultos en Quito e identificar posibles factores asociados. Métodos: Se realizó un estudio transversal en sujetos mayores a 18 años residentes en la ciudad de Quito-Ecuador. Se aplicó el cuestionario Global Asthma Network para recolectar información sobre síntomas de asma y datos sociodemográficas y de estilo de vida. Para la identificación de factores asociados con asma se utilizó análisis bivariados y multivariados con regresión logística. Resultados: Un total de 2,476 sujetos respondieron el cuestionario (80.9% mujeres, edad media 40 años). La prevalencia de sibilancias en los últimos 12 meses, asma alguna vez y asma diagnosticado por un médico fue de 6.3%; 1.9% y 1.6%, respectivamente. La prevalencia de rinitis y eczema alguna vez fue de 13.7% y 5.5%. La presencia de moho en el hogar (OR: 2.13; 95% IC: 1.48-3.06; p <0.001), gato en casa (OR: 1.06; 95% IC: 1.06-2.13; p <0.022) y rinitis alguna vez (OR: 3.65; 95% IC: 2.53-5.29; p <0.022) estaban asociados con la presencia de sibilancias en los últimos 12 meses. Conclusiones: Nuestro estudio muestra que, en comparación con otras ciudades de América Latina, la prevalencia de asma en adultos en Quito es relativamente baja. Junto con la presencia de rinitis, factores relacionados con la calidad de la vivienda están estrechamente ligados con la ocurrencia de asma en poblaciones adultas.

How reliably can algorithms identify eosinophilic asthma phenotypes using non-invasive biomarkers?

Background and Aims: Asthma is a heterogeneous respiratory disease that encompasses different inflammatory and functional endophenotypes. Many non-invasive biomarkers has been investigated to its pathobiology. Heany et al proposed a clinical algorithm that classifies severe asthmatic patients into likely-eosinophilic phenotypes, based on accessible biomarkers: PBE, current treatment, FeNO, presence of nasal polyps (NP) and age of onset. Materials and Methods: We assessed the concordance between the algorithm proposed by Heany et al. with sputum examination, the gold standard, in 145 asthmatic patients of the MEGA cohort with varying grades of severity. Results: No correlation was found between both classifications 0.025 (CI = 0.013-0.037). Moreover, no relationship was found between sputum eosinophilia and peripheral blood eosinophilia count in the total studied population. Discussion and Conclusion: In conclusion, our results suggest that grouping the biomarkers proposed by Heany et al. are insufficient to diagnose eosinophilic phenotypes in asthmatic patients. Sputum analysis remains the gold standard to assess airway inflammation.

Differences in Inflammatory Cytokine Profile in Obesity-Associated Asthma: Effects of Weight Loss.

Obesity and asthma are associated with systemic inflammation maintained by mediators released by adipose tissue and lung. This study investigated the inflammatory serum mediator profile in obese subjects (O) (n = 35), non-obese asthma (NOA) patients (n = 14), obese asthmatics (OA) (n = 21) and healthy controls (HC) (n = 33). The effect of weight loss after bariatric surgery (BS) was examined in 10 OA and 31 O subjects. We analyzed serum markers including leptin, adiponectin, TGF-ß1, TNFR2, MCP-1, ezrin, YKL-40, ST2, IL-5, IL-9, and IL-18. Compared with HC subjects, the O group showed increased levels of leptin, TGF-ß1, TNFR2, MCP-1, ezrin, YKL-40, and ST2; the OA group presented increased levels of MCP-1, ezrin, YKL-40, and IL-18, and the NOA group had increased levels of ezrin, YKL-40, IL-5, and IL-18. The higher adiponectin/leptin ratio in NOA with respect to OA subjects was the only significant difference between the two groups. IL-9 was the only cytokine with significantly higher levels in OA with respect to O subjects. TNFR2, ezrin, MCP-1, and IL-18 concentrations significantly decreased in O subjects after BS. O, OA, and NOA showed distinct patterns of systemic inflammation. Leptin and adiponectin are regulated in asthma by obesity-dependent and -independent mechanisms. Combination of asthma and obesity does not result in significant additive effects on circulating cytokine levels.

Reference Gene Validation for RT-qPCR in PBMCs from Asthmatic Patients with or without Obesity.

Obesity is known to impair the efficacy of glucocorticoid medications for asthma control. Glucocorticoid-induced gene expression studies may be useful to discriminate those obese asthmatic patients who present a poor response to glucocorticoids. The expression of genes of interest is normalized with respect to reference genes (RGs). Ideally, RGs have a stable expression in different samples and are not affected by experimental conditions. The objective of this work was to analyze suitable RGs to study the role of glucocorticoid-induced genes in obese asthmatic patients in further research. The gene expression of eight potential RGs (GUSB, B2M, POLR2A, PPIA, ACTB, GAPDH, HPRT1, and TBP) was assessed with reverse transcription-quantitative polymerase chain reaction in peripheral blood mononuclear cells (PBMCs) from asthmatic, obese asthmatic, and healthy individuals. Their stability was analyzed using four different algorithms-BestKeeper, ΔCt, geNorm, and NormFinder. geNorm analysis recommended the use of a minimum of three genes for normalization. Moreover, intergroup variation due to the treatment was calculated by NormFinder, which found that B2M was the gene that was least affected by different treatments. Comprehensive rankings indicated GUSB and HPRT1 as the best RGs for qPCR in PBMCs from healthy and asthmatic subjects, while B2M and PPIA were the best for obese asthmatic subjects. Finally, our results demonstrated that B2M and HPRT1 were the most stable RGs among all groups, whereas ACTB, TBP, and GAPDH were the worst shared ones.

Prevalence and associated factors for asthma in adults in Quito: a cross-sectional study / Prevalencia y factores asociados para asma en adultos en Quito: un estudio transversal

Abstract Background: Although several epidemiological studies of asthma have been carried out in Ecuador in the last two decades, none of these has estimated the prevalence of asthma in adult populations. Objective: To estimate the prevalence of asthma symptoms in adults in the city of Quito and to identify possible associated factors. Methods: A cross-sectional study was conducted on subjects older than 18 years residing in the Metropolitan District of Quito. The Global Asthma Network (GAN) questionnaire was applied to collect information on asthma symptoms and sociodemographic and lifestyle data. Bivariate and multivariate analyses with logistic regression were used to identify asthma-related factors. Results: 2,476 subjects answered the questionnaire (80.9% women, mean age 40 years). The prevalence of wheezing in the last 12 months, asthma ever, and asthma diagnosed by a doctor were 6.3%, 1.9% and 1.6%, respectively. The prevalence of rhinitis ever and eczema ever was 13.7% and 5.5%. The presence of mould at home (OR: 2.13; 95% CI: 1.48 -3.06; p <0.001), cat at home (OR: 1.06; 95% CI: 1.06 -2.13; p <0.022) and rhinitis at some time (OR: 3.65; 95% CI: 2.53 - 5.29; p <0.022) were associated with the presence of wheezing in the last 12 months. Conclusions: Our study shows that, compared to other cities in Latin America, the prevalence of asthma in adults in Quito is relatively low. Along with the presence of rhinitis, factors related to housing quality are closely linked to the occurrence of asthma in adult populations.

Resumen Antecedentes: Aunque en el Ecuador se han realizado varios estudios epidemiológicos de asma en las dos últimas décadas, ninguno de estos ha estimado la prevalencia de asma en poblaciones adultas. Objetivo: Estimar la prevalencia de síntomas de asma en adultos en Quito e identificar posibles factores asociados. Métodos: Se realizó un estudio transversal en sujetos mayores a 18 años residentes en la ciudad de Quito-Ecuador. Se aplicó el cuestionario Global Asthma Network para recolectar información sobre síntomas de asma y datos sociodemográficas y de estilo de vida. Para la identificación de factores asociados con asma se utilizó análisis bivariados y multivariados con regresión logística. Resultados: Un total de 2,476 sujetos respondieron el cuestionario (80.9% mujeres, edad media 40 años). La prevalencia de sibilancias en los últimos 12 meses, asma alguna vez y asma diagnosticado por un médico fue de 6.3%; 1.9% y 1.6%, respectivamente. La prevalencia de rinitis y eczema alguna vez fue de 13.7% y 5.5%. La presencia de moho en el hogar (OR: 2.13; 95% IC: 1.48-3.06; p <0.001), gato en casa (OR: 1.06; 95% IC: 1.06-2.13; p <0.022) y rinitis alguna vez (OR: 3.65; 95% IC: 2.53-5.29; p <0.022) estaban asociados con la presencia de sibilancias en los últimos 12 meses. Conclusiones: Nuestro estudio muestra que, en comparación con otras ciudades de América Latina, la prevalencia de asma en adultos en Quito es relativamente baja. Junto con la presencia de rinitis, factores relacionados con la calidad de la vivienda están estrechamente ligados con la ocurrencia de asma en poblaciones adultas.

Efficacy and safety of dupilumab in patients with uncontrolled severe chronic rhinosinusitis with nasal polyps and a clinical diagnosis of NSAID-ERD: Results from two randomized placebo-controlled phase 3 trials.

BACKGROUND: About one-tenth of patients with difficult-to-treat chronic rhinosinusitis with nasal polyps (CRSwNP) have comorbid non-steroidal anti-inflammatory drug-exacerbated respiratory disease (NSAID-ERD). Dupilumab, a fully human monoclonal antibody that blocks the shared interleukin (IL)-4/IL-13 receptor component, is an approved add-on treatment in severe CRSwNP. This post hoc analysis evaluated dupilumab efficacy and safety in patients with CRSwNP with/without NSAID-ERD. METHODS: Data were pooled from the phase 3 SINUS-24 and SINUS-52 studies in adults with uncontrolled severe CRSwNP who received dupilumab 300 mg or placebo every 2 weeks. CRSwNP, nasal airflow, lung function, and asthma control outcomes at Week 24 were evaluated, and treatment-subgroup interactions were assessed for patients with and without NSAID-ERD. RESULTS: Of 724 patients, 204 (28.2%) had a diagnosis of NSAID-ERD. At Week 24, least squares mean treatment differences demonstrated significant improvements in nasal polyp score, nasal congestion (NC), Lund-Mackay computed tomography, 22-item Sinonasal Outcome Test (SNOT-22), Total Symptom Score (TSS), rhinosinusitis severity visual analog scale, peak nasal inspiratory flow (PNIF), six-item Asthma Control Questionnaire score, and improvement in smell with dupilumab versus placebo (all p < .0001) in patients with NSAID-ERD. Treatment comparisons demonstrated significantly greater improvements with dupilumab in patients with versus without NSAID-ERD for NC (p = .0044), SNOT-22 (p = .0313), TSS (p = .0425), and PNIF (p = .0123). CONCLUSIONS: In patients with uncontrolled severe CRSwNP, dupilumab significantly improved objective measures and patient-reported symptoms to a greater extent in the presence of comorbid NSAID-ERD than without. Dupilumab was well tolerated in patients with/without NSAID-ERD.

Spectrum of Disease Manifestations in Patients with Selective Immunoglobulin E Deficiency.

BACKGROUND: Selective IgE deficiency (SIgED) has been previously evaluated in selected patients from allergy units. This study investigates the effects of SIgED on the entire population in a hospital setting and sought to delineate in detail the clinical aspects of SIgED. METHODS: A retrospective study of the data obtained from electronic medical records of 52 adult patients (56% female) with a mean age of 43 years and IgE levels of <2.0 kU/L with normal immunoglobulin (Ig) IgG, IgA, and IgM levels, seen at our hospital, without selection bias, from 2010 to 2019. RESULTS: Recurrent upper respiratory infections were recorded in 18 (34.6%) patients, pneumonia was recorded in 16 (30.7%) patients, bronchiectasis was recorded in 16 (30.7%) patients, and asthma was recorded in 10 (19.2%) patients. Eighteen patients (34.6%) suffered autoimmune clinical manifestations either isolated (19%) or combining two or more diseases (15%), Hashimoto's thyroiditis being the most frequent (19%), which was followed by arthritis (10%) and thrombocytopenia and/or neutropenia (5.7%). Other less frequent associations were Graves' disease, primary sclerosing cholangitis, Sjögren's syndrome, and autoimmune hepatitis. Eczematous dermatitis (15.3%), chronic spontaneous urticaria (17.3%), and symptoms of enteropathy (21%) were also highly prevalent. Thirty percent of patients developed malignancies, with non-Hodgkin lymphomas (13.4%) being the most prevalent. CONCLUSIONS: The clinical manifestations of SIgED encompass a variety of infectious, non-infectious complications, and malignancy. Since it cannot be ruled out that some type of selection bias occurred in the routine assessment of IgE serum Ievels, prospective studies are required to better characterize SIgED and to determine whether it should be added to the list of antibody deficiencies.