Alternative Drug Safety in Children with Nonsteroidal Anti-Inflammatory Drug Hypersensitivity.

INTRODUCTION: Nonsteroidal anti-inflammatory drugs (NSAIDs) are frequently used in the pediatric age group as pain relievers, antipyretics and anti-inflammatory drugs. Since NSAIDs are used in many medical conditions, there is a need for alternative NSAIDs to be used safely in people with hypersensitivity reactions. Selective and partially selective COX-2 inhibitors and weak COX-1 inhibitors are generally used as safe alternative drugs. The aim of this study was to evaluate safe NSAIDs determined by oral provocation tests (OPTs) according to phenotypes in children with NSAID hypersensitivity reactions. METHODS: The results of the oral provocation test performed with alternative NSAIDs (paracetamol, meloxicam, nimesulide, celecoxib) in patients followed up with the diagnosis of NSAID hypersensitivity reaction in the Pediatric Immunology and Allergy Department between January 2015 and February 2023 were evaluated retrospectively. RESULTS: During the study period, 91 patients underwent OPTs with 109 alternative drugs 48 (52.7%) of whom were girls, with a median age of 15 years. 91 patients had a history of reactions to 117 drugs. As an alternative NSAID; OPT was performed with paracetamol in 58 patients, meloxicam in 44 patients, nimesulide in 5 patients, and celecoxib in 2 patients. Since 15 patients used paracetamol safely at home, no tests were performed with paracetamol. Reactions were observed in 3 of the 73 patients (4.1%) who underwent OPT with paracetamol and in 2 of the 44 (4.5%) who underwent OPT with meloxicam. Reactions to nimesulide were also observed in the latter 2 patients (2/5, 40%), but they appeared to tolerate celecoxib. No reaction was observed in the 2 patients who were tested with celecoxib. CONCLUSION: Paracetamol, meloxicam, and nimesulide can be used as safe alternative drugs in most children with NSAID hypersensitivity. Selective COX-2 inhibitors should be tried as an alternative in patients who cannot tolerate them.

Vimentin filaments integrate low-complexity domains in a complex helical structure.

Intermediate filaments (IFs) are integral components of the cytoskeleton. They provide cells with tissue-specific mechanical properties and are involved in numerous cellular processes. Due to their intricate architecture, a 3D structure of IFs has remained elusive. Here we use cryo-focused ion-beam milling, cryo-electron microscopy and tomography to obtain a 3D structure of vimentin IFs (VIFs). VIFs assemble into a modular, intertwined and flexible helical structure of 40 α-helices in cross-section, organized into five protofibrils. Surprisingly, the intrinsically disordered head domains form a fiber in the lumen of VIFs, while the intrinsically disordered tails form lateral connections between the protofibrils. Our findings demonstrate how protein domains of low sequence complexity can complement well-folded protein domains to construct a biopolymer with striking mechanical strength and stretchability.

Surface Cross-Linking by Macromolecular Tethers Enhances Virus-like Particles' Resilience to Mucosal Stress Factors.

Virus-like particles (VLPs) are emerging as nanoscaffolds in a variety of biomedical applications including delivery of vaccine antigens and cargo such as mRNA to mucosal surfaces. These soft, colloidal, and proteinaceous structures (capsids) are nevertheless susceptible to mucosal environmental stress factors. We cross-linked multiple capsid surface amino acid residues using homobifunctional polyethylene glycol tethers to improve the persistence and survival of the capsid to model mucosal stressors. Surface cross-linking enhanced the stability of VLPs assembled from Acinetobacter phage AP205 coat proteins in low pH (down to pH 4.0) and high protease concentration conditions (namely, in pig and mouse gastric fluids). Additionally, it increased the stiffness of VLPs under local mechanical indentation applied using an atomic force microscopy cantilever tip. Small angle X-ray scattering revealed an increase in capsid diameter after cross-linking and an increase in capsid shell thickness with the length of the PEG cross-linkers. Moreover, surface cross-linking had no effect on the VLPs' mucus translocation and accumulation on the epithelium of in vitro 3D human nasal epithelial tissues with mucociliary clearance. Finally, it did not compromise VLPs' function as vaccines in mouse subcutaneous vaccination models. Compared to PEGylation without cross-linking, the stiffness of surface cross-linked VLPs were higher for the same length of the PEG molecule, and also the lifetimes of surface cross-linked VLPs were longer in the gastric fluids. Surface cross-linking using macromolecular tethers, but not simple conjugation of these molecules, thus offers a viable means to enhance the resilience and survival of VLPs for mucosal applications.

Development of anaphylaxis upon oral food challenge and drug provocation tests in pediatric patients.

Background: The drug provocation test (DPT) and the oral food challenge (OFC) are considered as the criterion standard for the diagnosis of drug hypersensitivity reactions and food allergy. Severe allergic reactions may develop during these tests. Objective: To evaluate the frequency and features of anaphylaxis in pediatric patients undergoing OFCs and DPTs. Method: OFCs and DPTs performed in an open method in the pediatric allergy clinic of our institution between January 2014 and January 2021 were reviewed retrospectively. The characteristics of anaphylaxis that developed during these tests were evaluated. Results: A total of 3631 OFCs and/or DPTs were performed on 2588 pediatric patients. Reactions were recorded in 317 challenges (8.7%), including 42 (1.2%) in the form of anaphylaxis. Of the patients with anaphylaxis, 31 developed anaphylaxis during OFC and 11 during DPT. Anaphylaxis during OFCs was mostly triggered by yogurt (n = 8), hen's egg (n = 6), baked milk (n = 5), and baked egg (n = 4). Cases with anaphylaxis during DPT were recorded mostly with ibuprofen (54.5% [n = 6]). All patients who developed anaphylaxis during OFC had cutaneous manifestations, and 90.3% had respiratory symptoms. Gastrointestinal involvement was present in 32.3% of the patients. During DPT, cutaneous manifestations were observed in 90.9% in the patients who developed anaphylaxis and the respiratory tract was involved in 81.8%. In terms of concomitant allergic diseases, 51.6% of the patients who developed anaphylaxis during OFC had atopic dermatitis and 38.7% had asthma. All the patients with anaphylaxis triggered by nonsteroidal anti-inflammatory drug DPT had asthma. Of the anaphylaxis, 54.8% were mild, 35.7% were moderate, and 9.5% were severe. Severe anaphylaxis was recorded with baked milk (n = 2), baked egg and trimethoprim-sulfamethoxazole (n = 1, each). The patients did not require intensive care, and no death occurred. Conclusion: Anaphylaxis may develop during OFCs and DPTs. These tests should be carried out by experienced allergists in an appropriate setting where emergency equipment and medications, including epinephrine, are readily available.

Nanoscale clustering by O-antigen-Secretory Immunoglobulin-A binding limits outer membrane diffusion by encaging individual Salmonella cells.

Secreted immunoglobulins, predominantly SIgA, influence the colonization and pathogenicity of mucosal bacteria. While part of this effect can be explained by SIgA-mediated bacterial aggregation, we have an incomplete picture of how SIgA binding influences cells independently of aggregation. Here we show that akin to microscale crosslinking of cells, SIgA targeting the Salmonella Typhimurium O-antigen extensively crosslinks the O-antigens on the surface of individual bacterial cells at the nanoscale. This crosslinking results in an essentially immobilized bacterial outer membrane. Membrane immobilization, combined with Bam-complex mediated outer membrane protein insertion results in biased inheritance of IgA-bound O-antigen, concentrating SIgA-bound O-antigen at the oldest poles during cell growth. By combining empirical measurements and simulations, we show that this SIgA-driven biased inheritance increases the rate at which phase-varied daughter cells become IgA-free: a process that can accelerate IgA escape via phase-variation of O-antigen structure. Our results show that O-antigen-crosslinking by SIgA impacts workings of the bacterial outer membrane, helping to mechanistically explain how SIgA may exert aggregation-independent effects on individual microbes colonizing the mucosae.

Mechanical tuning of virus-like particles.

HYPOTHESIS: Virus-like particles (VLPs) are promising scaffolds for developing mucosal vaccines. For their optimal performance, in addition to design parameters from an immunological perspective, biophysical properties may need to be considered. EXPERIMENTS: We investigated the mechanical properties of VLPs scaffolded on the coat protein of Acinetobacter phage AP205 using atomic force microscopy and small angle X-ray scattering. FINDINGS: Investigations showed that AP205 VLP is a tough nanoshell of stiffness 93 ± 23 pN/nm and elastic modulus 0.11 GPa. However, its mechanical properties are modulated by attaching muco-inert polyethylene glycol to 46 ± 10 pN/nm and 0.05 GPa. Addition of antigenic peptides derived from SARS-CoV2 spike protein by genetic fusion increased the stiffness to 146 ± 54 pN/nm although the elastic modulus remained unchanged. These results, which are interpreted in terms of shell thickness and coat protein net charge variations, demonstrate that surface conjugation can induce appreciable changes in the biophysical properties of VLP-scaffolded vaccines.

Psychological Distress and Drug Provocation Test-Related Anxiety Levels of Pediatric Patients and Their Parents.

Background: Drug provocation tests (DPTs) are the gold standard for the diagnosis of drug hypersensitivity reaction (DHR). To the best of our knowledge, there is no previous study reporting DPT-related anxiety levels in children and their parents. This study aimed to determine the difference in pre- and post-DPT anxiety levels of parents and children who were informed of the possibility of another DHR during the DPT, and to evaluate the relationship between parental psychological distress and anxiety levels. Methods: The study included children who underwent DPT in our clinic between July 1, 2019, and February 29, 2020, and accompanying parents who consented to participate. Age-appropriate State-Trait Anxiety Inventory scales were used to assess levels of state and trait anxiety in the patients and parents. The Symptom Checklist-90-Revised (SCL-90-R) was used to screen for psychological symptoms in parents. Results: Data were collected from the parents of 69 children who underwent DPTs. The patients' median age was 7.28 (interquartile range: 4.52-10.06) and their parents' mean age was 35.28 ± 5.38 years. Anxiety-related data were collected from 21 pediatric patients. The children and parents had higher state anxiety scores before DPT compared to after DPT. There was a positive correlation between the parents' trait anxiety and pre-DPT state anxiety scores. In addition, parental pre-DPT state anxiety scores were positively correlated with SCL-90-R general severity index, somatization, anxiety, obsessive-compulsive, and depression subscale scores. Conclusion: The risk of allergic reaction in DPT may cause anxiety. A high level of parental anxiety before DPT, which gradually decreased after negative test results, was associated with history of drug-induced anaphylaxis in their children and high trait anxiety. Appropriate evaluation of patients and parents before DPT and providing detailed information may be important to reduce this anxiety.

The Etiology, Clinical Features, and Severity of Anaphylaxis in Childhood by Age Groups.

INTRODUCTION: Anaphylaxis is a severe, potentially fatal systemic hypersensitivity reaction with an acute onset. Etiology, clinical presentation, risk factors, comorbidities of pediatric anaphylaxis may vary depending on the age of the child. OBJECTIVE: The aim of this study was to investigate the etiology, clinical features, management of anaphylaxis in infants, preschoolers, school-age children, and adolescents. METHODS: The patients presenting with anaphylaxis between January 2015 and December 2018 in a single pediatric tertiary hospital were evaluated retrospectively. Demographic data, the triggers, sign-symptoms, severity, and the management of anaphylaxis were recorded. RESULTS: 239 patients were included in the study, 62.3% of whom were boys. The median age was 6.7 (IQR 2.33-12.83) years. 23.8% of the patients were infants, 15.5% were preschoolers, 33.5% were school-age children, and 27.2% were adolescents. Anaphylaxis mostly occurred at home. The most common causative agents were foods (39.3%), drugs (30.1%), and venoms (15.9%) of all cases. Main food allergens were cow's milk and hen's eggs in infants, cow's milk and tree nuts in preschoolers, and tree nuts and legumes in school-age children. Cases of drug-induced anaphylaxis (DIA) were recorded mostly with antibiotics (40.3%), followed by NSAIDs (23.6%). The primary trigger of anaphylaxis was foods in infants and preschoolers and drugs in school-age children and adolescents. There was no difference between age groups in terms of the system involved and severity. Severe anaphylaxis was more common with DIA. Adrenaline was used in 69.8% of all cases with no significant difference between age groups. CONCLUSION: Etiology and symptoms of anaphylaxis may differ between age groups. Raising awareness, educating patients and their parents on anaphylaxis and its management is essential.

Evaluation of anaphylaxis recurrence and adrenaline autoinjector use in childhood.

Introduction: Limited data are available on recurrent anaphylaxis in childhood. Delayed adrenaline administration is the major cause of deaths due to anaphylaxis. As well as prescribing the adrenaline autoinjector (AAI), it is important to make sure that the patient carries the device at all times and uses it correctly for the appropriate indication. Objective: The aim of our study was to evaluate the recurrence of anaphylaxis and AAI use in childhood. Methods: Pediatric patients who were evaluated for anaphylaxis and prescribed AAI between January 2015 and December 2018, in the pediatric allergy and immunology clinic of our hospital were screened retrospectively. A telephone-based survey was conducted with the parents of the patients to investigate the recurrence of anaphylaxis in patients and the use of AAI by their parents for the management of anaphylaxis. Results: A total of 148 patients (64.9% boys) were prescribed an AAI for anaphylaxis. The telephone survey could be conducted with 111 parents (75%) with an AAI prescription. Of these patients, 23.4% (n = 26) of the parents reported that their children experienced recurrent episodes of anaphylaxis. In the recurrent anaphylaxis cases, the triggers were foods in 77%, venoms in 11.5%, drugs in 3.8%, and idiopathic anaphylaxis in 7.7% of the patients. AAI use at the time of anaphylaxis was reported by 42.3% of the parents. The reasons cited by the parents for not using AAI during an episode of anaphylaxis included the preference to have adrenaline administered at a health care facility because of its proximity (60%), fear of using the device (13.3%), hesitation (6.7%), not having the device with them (13.3%), and unavailability of the device (6.7%). Conclusion: Educating the patients and families about the importance of using AAI is crucial, and training on how to use the device should be repeated at each clinic visit and every opportunity.

Evaluation of Clinical Properties and Diagnostic Test Results of Cephalosporin Allergy in Children.

INTRODUCTION: Beta-lactams (BLs) are one of the most frequent causes of drug hypersensitivity reactions (HRs), and cephalosporins are a widely used subclass of BLs, especially in children. The aim of this study was to evaluate the clinical features and diagnostic test results of pediatric patients evaluated for suspected cephalosporin allergy. METHODS: This study included patients who presented to our pediatric allergy clinic with a history of reactions attributed to cephalosporins between January 1, 2011, and December 31, 2019, and whose diagnostic tests were completed for the diagnosis. RESULTS: This study included 120 pediatric patients and 69 (57.5%) of them were girls. The median age was 38.63 (interquartile range 10.5-85.7) months. Reactions occurring within 1 h of drug intake were reported in 33 patients (27.5%). Reactions were maculopapular rash in 55 (45.8%) patients, urticaria and/or angioedema in 49 (40.8%), anaphylaxis in 11 (9.2%), severe cutaneous drug reaction in 4 (3.3%), and fixed drug reaction in 1 patient (0.83%). The most frequently suspected agent was cefixime in 41 patients (34.2%). In total, 30 (25%) patients were diagnosed as having cephalosporin hypersensitivity. Confirmation of HRs was also significantly more frequent among patients who were older (p: 0.000), who had taken the drug parenterally (p: 0.000) and with immediate reactions (p: 0.000). CONCLUSION: Cephalosporin allergy has been confirmed in approximately one-fourth of the patients evaluated for suspected cephalosporin allergy. Confirmation of HRs was significantly more common among patients who were older, had immediate reactions, and had taken the drug parenterally.