Hypersensitivity to Gadolinium-Based Contrast Media.

Gadolinium-based contrast agents (GBCAs) are frequently used in magnetic resonance imaging (MRI) examinations to increase sensitivity in diagnoses. Recently, an increase in the description of hypersensitivity reactions to GBCAs has been detected. We performed research in PubMed, PubMed, SCOPUS, and EMBASE until September 2021, searching for studies regarding immediate and delayed hypersensitivity reactions to gadolinium-based contrast agents in which an allergy study was performed. The initial research identified 149 articles written in English. After excluding articles duplicated and articles that had irrelevant designs, 26 articles were included. Finally, 17 studies concerning immediate reactions, six studies concerning non-immediate reactions, and three concerning both that performed allergy evaluations were selected. In the review, we analyzed the characteristics of immediate and delayed reactions and the results of the allergy study and cross-reactivity. Skin tests seem to have acceptable accuracy, but drug provocation tests are still needed when skin tests are negative o to find alternative agents. Although cross-reactivity patterns are not well established, cross-reactivity seems to exist among macrocyclic agents. Notwithstanding, the number of patients analyzed is low and further studies are required. A management algorithm is suggested.

Angioedema Due to Acquired Deficiency of C1-Inhibitor: A Cohort Study in Spain and a Comparison With Other Series.

BACKGROUND: Data on acquired angioedema due to C1-inhibitor deficiency (C1-INH-AAE) from 4 European countries (France, Italy, Germany, and Hungary) were recently published. OBJECTIVE: To report data from a group of 50 patients with acquired C1-INH deficiency from Spain, of whom 46 had angioedema, and compare them with other European series. METHODS: We performed a retrospective observational study of 46 patients with C1-INH-AAE and 4 asymptomatic patients. Clinical and biological characteristics and associated diseases were assessed and compared with other European series. RESULTS: Women accounted for 73.9% of cases. The prevalence of C1-INH-AAE related to hereditary forms was 1/10.1. Overall, 8.7% patients were aged <40 years. Diagnostic delay was 1.1 years. Angioedema mainly affected the face (91.3%), followed by the oropharynx (63%), extremities (50%), and abdomen (37%). Only 1 patient underwent orotracheal intubation. Erythema marginatum was present in 1 patient. A hematologic disorder was recorded in 50% of patients. Angioedema preceded all benign conditions, mostly monoclonal gammopathy of undetermined significance, but appeared very close to or after malignant hematologic diseases (median, 2.2 and 0.29 years). Autoimmune diseases were associated in 50% (autoimmune thyroiditis, 21.5%; systemic lupus erythematosus, 10.9%). Half of them coexisted with hematologic disorders. Anti-C1-INH antibodies were found in 67% of tested patients and were not related to the associated disease. Long-term prophylaxis was necessary in 52.2%, most of whom responded to tranexamic acid. CONCLUSIONS: This study emphasizes the possibility of C1-INH-AAE in patients younger than 40 and in autoimmune diseases other than systemic lupus erythematosus such as autoimmune thyroiditis.

Usefulness of an Artificial Neural Network in the Prediction of ß-Lactam Allergy.

BACKGROUND: An accurate diagnosis of ß-lactam (BL) allergy improves the use of antibiotics, increases patients' safety, and reduces costs to health systems. Nevertheless, it requires skin and drug provocation tests, which are time-consuming and put the patient at risk. Furthermore, allergy testing is not available in circumstances such as the urgent need for antibiotic therapy. OBJECTIVE: To evaluate the usefulness of an artificial neural network (ANN) in the prediction of hypersensitivity to BLs, and compare it with logistic regression (LR) analysis. METHODS: In a single-center study, 656 patients evaluated for BL allergy between 1994 and 2000 were retrospectively analyzed, and the data were used to construct an ANN. The ANN predictive capabilities were compared with LR and then prospectively evaluated in 615 patients who underwent BL evaluation between 2011 and 2017. RESULTS: A total of 1271 patients were evaluated. All patients had a definite diagnosis as allergic or nonallergic to BL. The prospective sample showed a lower percentage of patients with allergy than the retrospective sample (20.7% vs 25.8%; P = .018). In the retrospective and prospective series, the ANN reached a sensitivity of 89.5% and 81.1%, a specificity of 86.1% and 97.9%, a positive predictive value of 82.1% and 91.1%, and a negative predictive value of 92.1% and 95.2%, respectively. The ANN's performance was far superior to that of the LR, whose best performance reached a sensitivity of 31.9% and a specificity of 98.8%. CONCLUSIONS: This ANN demonstrated a superior performance than the LR in predicting BL hypersensitivity without misdiagnosing severe allergic reactions. The ANN could be a helpful tool to classify the reaction risk, particularly in the identification of low-risk patients, in which an open challenge could be done to delabel patients.

Analysis of the Costs Associated With the Elective Evaluation of Patients Labelled as Allergic to Beta-Lactams or Nonsteroidal Antiinflamatory Agents.

Introduction: Being labelled as allergic to different drugs results in patients receiving other treatments, which are more toxic, less effective and more expensive. We aimed to analyze different studies of the costs of drug hypersensitivity assessment. Methods: A bibliographic search on studies regarding this issue was performed, including the available scientific evidence up to June 2020. We searched three databases with terms related to costs and allergy testing in drug hypersensitivity reactions. Results: Our search revealed 1,430 publications, of which 20 met the inclusion criteria. In the manuscript, prospective studies evaluating the costs of the evaluation of patients with suspected allergy to beta-lactams or non-steroidal anti-inflammatory drugs are analyzed. Also, comment is made on the costs associated with incorrect labeling as non-steroidal anti-inflammatory drug or penicillin hypersensitivity. Conclusions: Taking all costs into account, the study of drug hypersensitivity is not expensive, particularly considering the economic and clinical consequences of labeling a patient with hypersensitivity to drugs.

Molecular analysis of activation-induced cytidine deaminase gene in immunoglobulin-E deficient patients.

Understanding how class switch recombination (CSR) is regulated to produce immunoglobulin E (IgE) has become fundamental because of the dramatic increase in the prevalence of IgE-mediated hypersensitivity reactions. CSR requires the induction of the enzyme AICDA in B cells. Mutations in AICDA have been linked to Hyper-IgM syndrome (HIGM2), which shows absence of switching to IgE as well as to IgG and IgA. Although isolated IgE deficiency is a rare entity, here we show some individuals with normal serum IgM, IgG, and IgA levels that had undetectable total serum IgE levels. We have analyzed the AICDA gene in these individuals to determine if there are mutations in AICDA that could lead to selective IgE deficiency. Conformational sensitive gel electrophoresis (CSGE) and sequencing analysis of AICDA coding sequences demonstrated sequence heterogeneity due to 5923A/G and 7888C/T polymorphisms, but did not reveal any novel mutation that might explain the selective IgE deficit.

Cluster Analysis Identifies 3 Phenotypes within Allergic Asthma.

BACKGROUND: Asthma is a heterogeneous chronic disease with different clinical expressions and responses to treatment. In recent years, several unbiased approaches based on clinical, physiological, and molecular features have described several phenotypes of asthma. Some phenotypes are allergic, but little is known about whether these phenotypes can be further subdivided. OBJECTIVE: We aimed to phenotype patients with allergic asthma using an unbiased approach based on multivariate classification techniques (unsupervised hierarchical cluster analysis). METHODS: From a total of 54 variables of 225 patients with well-characterized allergic asthma diagnosed following American Thoracic Society (ATS) recommendation, positive skin prick test to aeroallergens, and concordant symptoms, we finally selected 19 variables by multiple correspondence analyses. Then a cluster analysis was performed. RESULTS: Three groups were identified. Cluster 1 was constituted by patients with intermittent or mild persistent asthma, without family antecedents of atopy, asthma, or rhinitis. This group showed the lowest total IgE levels. Cluster 2 was constituted by patients with mild asthma with a family history of atopy, asthma, or rhinitis. Total IgE levels were intermediate. Cluster 3 included patients with moderate or severe persistent asthma that needed treatment with corticosteroids and long-acting ß-agonists. This group showed the highest total IgE levels. CONCLUSIONS: We identified 3 phenotypes of allergic asthma in our population. Furthermore, we described 2 phenotypes of mild atopic asthma mainly differentiated by a family history of allergy.

Using ß-lactam antibiotics in patients with a history of ß-lactam allergy: current concepts.

ß-lactams are the most widely used antibiotic family, but they are also the most common cause of drug-induced hypersensitivity reactions. The estimated prevalence of reported penicillin allergy ranges between 9% and 12%, although a high percentage of patients with a history of penicillin allergy have no subsequent reactions on reexposure to ß-lactams. A self-reported penicillin allergy has been associated with antimicrobial resistance, increased cost, intensive care admission, and death, making it essential to establish an accurate diagnosis. In addition to a thorough clinical history, diagnostic methods include skin tests, in vitro tests, and drug-challenge tests. In this review, the diagnosis and management of patients with self-reported penicillin allergy is discussed, including the recently introduced antimicrobial stewardship strategy.

Interleukin-4 (IL4) and Interleukin-4 receptor (IL4RA) polymorphisms in asthma: a case control study.

BACKGROUND: IL4/IL4RA pathway plays an important role in atopy and asthma. Different polymorphisms in IL4 and IL4RA genes have been described. Particularly, -33C>TIL4 and 576Q>RIL4RA SNPs have been independently associated to atopy and asthma. The purpose of this study was to analyse these polymorphisms in a population of patients with a well-characterized asthma phenotype. METHODS: A total of 212 unrelated Caucasian individuals, 133 patients with asthma and 79 healthy subjects without symptoms or history of asthma or atopy and with negative skin prick tests were recruited. Lung function was measured by spirometry and asthma was specialist physician-diagnosed according to the ATS (American Thoracic Society) criteria and classified following the GINA (Global Initiative for Asthma) guidelines. Skin prick tests were performed according to EAACI recommendations. -33C>TIL4 was studied with TaqMan assay and 576Q>RIL4RA by PCR-RFLP technique. Hardy-Weinberg equilibrium was analysed in all groups. Dichotomous variables were analysed using chi2, Fisher exact test, Monte Carlo simulation test and odds ratio test. To model the effects of multiple covariates logistic regression was used. RESULTS: No statistically significant differences between the group of patients with asthma and the controls were found when the allele and genotype distribution of -33C>TIL4 and 576Q>RIL4RA polymorphisms were compared. However, the T allele of the -33C>TIL4 SNP was more frequent in patients with persistent asthma. Multivariate analysis adjusted for age and sex confirmed that carriers of allele T had an increased risk of persistent asthma (OR: 2.77, 95%CI: 1.18-6.49; p = 0.019). Analysis of combination of polymorphisms showed that patients carrying both the T allele of -33C>TIL4 and the A allele of 576Q>RIL4RA had an increased risk of asthma. This association was particularly observed in persistent asthma [Fisher's p value = 0.0021, Monte Carlo p value (after 10(4) simulations) = 0.0016, OR:3.39; 95% CI:1.50-7.66]. CONCLUSION: Our results show a trend of association between the genetic combination of the T allele of -33C>TIL4 and the A allele of 576Q>RIL4RA with asthma. This genetic variant was more frequently observed in patients with persistent asthma. As long as this study was performed in a small population, further studies in other populations are needed to confirm these results.

[IL4RA gene polymorphism (Q576R) is associated with higher total IgE levels in Spanish patients with family history of atopy]. / El polimorfismo Q576R del gen IL4RA se asocia con valores elevados de IgE total en pacientes con antecedentes familiares de atopia.

BACKGROUND AND OBJECTIVE: Atopy is a common immunological disorder underlying allergic rhinitis, atopic dermatitis and allergic asthma. There is an association between atopy and the polymorphism Q576R in the IL4RA gene. The aim of this study is to analyze the allelic distribution of the Q576R polymorphism in an atopic and non atopic population and the relationship with total IgE levels and the family history of atopy. PATIENTS AND METHOD: Q576R polymorphism of IL4RA gene was analyzed by PCR-restriction fragment length polymorphism (RFLP) using MspI restriction enzyme in 154 patients from the Allergy Department of the University Hospital of Salamanca. RESULTS: We have not found an association between the R576 allele and higher serum IgE levels nor atopy in this population. Nevertheless, there is an association between this allele and IgE levels in patients with positive skin prick test and family history of atopy. CONCLUSIONS: Our results suggest that the R576 allele could characterize a specific group of patients with a familial history of atopy in whom the presence of this allele may be related to higher levels of serum IgE.

Hypersensitivity reactions to cephalosporins.

At present, cephalosporins represent one of the most prescribed classes of antibiotics. Although allergic reactions have been estimated to be infrequent, the number of reactions to cephalosporins is increasing due to their wide use. Cross-reactivity with penicillins has mainly been evaluated in patients with penicillin allergy. It is higher between first- and second-generation cephalosporins with the same or similar side chain than between cephalosporins with different side chains. Unlike penicillins, cephalosporin haptens or determinants have not been defined, and therefore the diagnosis is complicated. Nevertheless, skin tests with cephalosporins are useful in the evaluation of several allergic reactions. Although more studies are necessary, a negative result in skin testing to penicillin and cephalosporins with different side chains seems to be a good predictor of tolerance, and could be used in select cases.