Characterization of amoxicillin and clavulanic acid specific T-cell clones from patients with immediate drug hypersensitivity

BACKGROUND

Betalactam (BL) antibiotics are the most common cause of drug hypersensitivity. Amoxicillin (AX), which is often prescribed alongside clavulanic acid (Clav), is the most common elicitor. The aim of this study was to determine whether AX and Clav-responsive T-cells are detectable in patients with immediate hypersensitivity to AX-Clav, to assess whether these T-cells display the same specificity as that detected in skin and provocation testing, and to explore T-cell activation pathways.

METHODS

Drug-specific T-cell clones were generated from immediate hypersensitive patients´ blood by serial dilution and repetitive mitogen stimulation. Antigen specificity was assessed by measurement of proliferation and cytokine release. CD4+ /CD8+ phenotype and chemokine receptor expression were analyzed by flow cytometry.

RESULTS

110 AX-specific and 96 Clav-specific T-cell clones were generated from seven patients with positive skin test to either AX or Clav. Proliferation of AX- and Clav-specific clones was dose-dependent, and no cross-reactivity was observed. AX- and Clav-specific clones required antigen-presenting cells to proliferate, and drugs were presented to CD4+ and CD8+ T-cells by MHC class-II and I, respectively. A higher secretion of IL-13 and IL-5 was detected in presence of the culprit drug compared with the alternative drug. Clones expressed CD69, CCR4, CXCR3, and CCR10.

CONCLUSIONS

Our study details the antigen specificity and phenotype of T-cell clones generated from patients with AX-Clav-induced immediate hypersensitivity diagnosed by positive skin test. AX- and Clav-specific clones were generated from patients irrespective of whether AX or Clav was the culprit, although differences in cytokine secretion were observed.

Hypersensitivity Reactions to Multiple Iodinated Contrast Media

The incidence of hypersensitivity reactions (HSRs) to iodinated contrast media (ICM) has risen over last years, representing an important health problem. HSRs to ICMs are classified into immediate reactions (IRs) and non-immediate reactions (NIRs) according to if they occur within 1 h or longer after ICM administration. The diagnosis of HSRs to ICM is complex as skin test (ST) sensitivity ranges widely, and drug provocation test (DPT) protocols are heterogeneous. In this manuscript, we describe the clinical characteristics of a series of patients confirmed as HSR to ICM and the diagnosis procedure carried out, looking into those cases confirmed as HSRs to multiple ICMs. For this purpose, we prospectively evaluated patients suggestive of HSRs to ICMs and classified them as IRs or NIRs. STs were carried out using a wide panel of ICMs, and in those with a negative ST, a single-blind placebo controlled DPT was performed with the culprit. If ST or DPT were positive, then tolerance was assessed with an alternative negative ST ICM. We included 101 cases (12 IRs and 89 NIRs) confirmed as allergic. Among them, 36 (35.64%) cases were allergic to more than one ICM (8 IRs and 28 NIRs). The most common ICM involved were iomeprol and iodixanol. Although not statistically significant, the percentage of patients reporting anaphylaxis was higher in patients allergic to multiple ICMs compared with patients allergic to a single ICM (50 vs. 25%). Likewise, the percentage of positive results in STs was higher in patients allergic to multiple ICMs compared with those allergic to a single ICM (for IR 62.5 vs. 25%, p > 0.05; and for NIR, 85.71 vs. 24.59%, p < 0.000). In cases allergic to more than one ICM, DPT with negative-ST ICM was positive in more than 60% (24/36) of cases. Therefore, allergy to multiple ICMs is common, associated to severe reactions in IRs, and confirmed frequently by positive STs. The allergological work-up should include DPT not only to establish the diagnosis but also to identify safe alternative ICM, even if ICM is structurally unrelated and ST is negative. More studies are needed to clarify mechanisms underlying cross-reactivity among ICMs.

Secreted protein acidic and rich in cysteine (SPARC) induces epithelial-mesenchymal transition, enhancing migration and invasion, and is associated with high Gleason score in prostate cancer

Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein highly expressed in bone tissue that acts as a chemoattractant factor promoting the arrival of prostate cancer (PCa) cells to the bone marrow. However, the contribution of SPARC during the early stages of tumor progression remains unclear. In this study, we show that SPARC is highly expressed in PCa tissues with a higher Gleason score. Through stable knockdown and overexpression of SPARC in PC3 and LNCaP cells, respectively, here we demonstrate that endogenous SPARC induces the epithelial-mesenchymal transition (EMT), decreasing E-cadherin and cytokeratin 18 and increasing N-cadherin and vimentin. Moreover, SPARC induces the expression of EMT regulatory transcription factors Snail family transcriptional repressor 1 (Snail), Snail family transcriptional repressor 2 (Slug), and zinc finger E-box binding homeobox 1 (Zeb1). In addition, SPARC knockdown in PC3 cells decreases migration and invasion in vitro, without modifying cell proliferation. Our results indicate that SPARC might facilitate tumor progression by modifying the cellular phenotype in cancer cells.

ARADyAL: The Spanish Multidisciplinary Research Network for Allergic Diseases

Thematic cooperative health research networks (RETICS) are organizational structures promoted by the Instituto de Salud Carlos III of the Spanish Ministry of Science with the objective of carrying out cooperative research projects addressing challenges of general interest for society as a whole in the field of health care. The RETICS of Asthma, Adverse Drug Reactions, and Allergy (ARADyAL) received funding in 2016 for a 5-year program (2017-2021). ARADyAL integrates basic and clinical research in the areas of allergy, immunology, genetics, nanomedicine, pharmacology, and chemistry, with special interest in research on new biomarkers and the design and evaluation of new interventions for allergic patients with severe phenotypes. The consortium comprises 28 groups across Spain, including 171 clinical and basic researchers, 17 clinical groups that cover more than 10 000 000 patients of all ages from urban and rural areas and 11 basic groups active mostly at universities and research institutes. ARADyAL has proposed a research program organized into 3 different areas focusing on precision medicine, as follows: Program 1, Mechanisms and prediction of adverse drug reactions and allergic diseases; Program 2, Toward a precise diagnosis of allergic diseases; and Program 3, Predicting interventions in allergic diseases. There is also 1 common program dedicated to training. The network has a Steering Committee and an External Advisory Scientific Committee, which advise the global network coordinator, who has recognized expertise in the field. ARADyAL is a unique meeting point for clinicians and basic scientists who are already working in allergy.

PPARβ/δ-dependent MSC metabolism determines their immunoregulatory properties

Mesenchymal stem cell (MSC)-based therapy is being increasingly considered a powerful opportunity for several disorders based on MSC immunoregulatory properties. Nonetheless, MSC are versatile and plastic cells that require an efficient control of their features and functions for their optimal use in clinic. Recently, we have shown that PPARβ/δ is pivotal for MSC immunoregulatory and therapeutic functions. However, the role of PPARβ/δ on MSC metabolic activity and the relevance of PPARβ/δ metabolic control on MSC immunosuppressive properties have never been addressed. Here, we demonstrate that PPARβ/δ deficiency forces MSC metabolic adaptation increasing their glycolytic activity required for their immunoregulatory functions on Th1 and Th17 cells. Additionally, we show that the inhibition of the mitochondrial production of ATP in MSC expressing PPARβ/δ, promotes their metabolic switch towards aerobic glycolysis to stably enhance their immunosuppressive capacities significantly. Altogether, these data demonstrate that PPARβ/δ governs the immunoregulatory potential of MSC by dictating their metabolic reprogramming and pave the way for enhancing MSC immunoregulatory properties and counteracting their versatility.

Towards a more precise diagnosis of hypersensitivity to beta-lactams - an EAACI position paper

A recent survey of the European Academy of Allergy and Clinical Immunology (EAACI) Drug Allergy Interest Group (DAIG) on how European allergy specialists deal with beta-lactam (BL) hypersensitivity demonstrated a significant heterogeneity in current practice, suggesting the need to review and update existing EAACI guidelines in order to make the diagnostic procedures as safe and accurate, but also as cost-effective, as possible. For this purpose, a bibliographic search on large studies regarding BL hypersensitivity diagnosis was performed by an EAACI task force, which reviewed and evaluated the literature data using the GRADE system for quality of evidence and strength of recommendation. The updated guidelines provide a risk stratification in BL hypersensitivity according to index reaction(s), as well as an algorithmic approach, based on cross-reactivity studies, in patients with a suspicion of BL hypersensitivity and an immediate need for antibiotic therapy, when referral to an allergist is not feasible. Furthermore, the update addresses availability and concentrations of skin test (ST) reagents, ST and drug provocation test (DPT) protocols, and diagnostic algorithms and administration of alternative BL in allergic subjects. Specifically, distinct diagnostic algorithms are suggested depending on risk stratification of the patient into high and low risk based on the morphology and chronology of the reaction, immediate (ie, occurring within 1-6 hours after the last administered dose) or nonimmediate (ie, occurring more than 1 hour after the initial drug administration), and the reaction severity. Regarding the allergy workup, the main novelty of this document is the fact that in some low-risk nonimmediate reactions ST are not mandatory, especially in children. For DPT, further studies are necessary to provide data supporting the standardization of protocols, especially of those regarding nonimmediate reactions, for which there is currently no consensus.

Towards a more precise diagnosis of hypersensitivity to beta-lactams - an EAACI position paper

A recent survey of the European Academy of Allergy and Clinical Immunology (EAACI) Drug Allergy Interest Group (DAIG) on how European allergy specialists deal with beta-lactam (BL) hypersensitivity demonstrated a significant heterogeneity in current practice, suggesting the need to review and update existing EAACI guidelines in order to make the diagnostic procedures as safe and accurate, but also as cost-effective, as possible. For this purpose, a bibliographic search on large studies regarding BL hypersensitivity diagnosis was performed by an EAACI task force, which reviewed and evaluated the literature data using the GRADE system for quality of evidence and strength of recommendation. The updated guidelines provide a risk stratification in BL hypersensitivity according to index reaction(s), as well as an algorithmic approach, based on cross-reactivity studies, in patients with a suspicion of BL hypersensitivity and an immediate need for antibiotic therapy, when referral to an allergist is not feasible. Furthermore, the update addresses availability and concentrations of skin test (ST) reagents, ST and drug provocation test (DPT) protocols, and diagnostic algorithms and administration of alternative BL in allergic subjects. Specifically, distinct diagnostic algorithms are suggested depending on risk stratification of the patient into high and low risk based on the morphology and chronology of the reaction, immediate (ie, occurring within 1-6 hours after the last administered dose) or nonimmediate (ie, occurring more than 1 hour after the initial drug administration), and the reaction severity. Regarding the allergy workup, the main novelty of this document is the fact that in some low-risk nonimmediate reactions ST are not mandatory, especially in children. For DPT, further studies are necessary to provide data supporting the standardization of protocols, especially of those regarding nonimmediate reactions, for which there is currently no consensus.

Clinical Characterization and Diagnostic Approaches for Patients Reporting Hypersensitivity Reactions to Quinolones

BACKGROUND

Quinolones are the second most frequent cause of hypersensitivity reactions (HSRs) to antibiotics. A marked increase in the number of patients with HSRs to quinolones has been detected.

OBJECTIVE

To describe the clinical characteristics of patients with HSRs to quinolones and present methods for their diagnosis.

METHODS

Patients attending the allergy unit due to reactions suggestive of HSRs to quinolones were prospectively evaluated between 2005 and 2018. Diagnosis was achieved using clinical history, skin tests (STs), basophil activation tests (BATs), and drug provocation tests (DPTs) if ST and BAT results were negative.

RESULTS

We included 128 subjects confirmed as having HSRs to quinolones and 42 found to be tolerant. Anaphylaxis was the most frequent entity in immediate HSRs and was most commonly induced by moxifloxacin. Patients were evaluated a median of 150 days (interquartile range, 60-365 days) after the reaction. Of patients who underwent ST and BAT, 40.7% and 70%, respectively, were positive. DPT with a quinolone was performed in 48 cases, giving results depending on the culprit drug: when moxifloxacin was involved, 62.5% of patients gave a positive DPT result to ciprofloxacin, whereas none reacted to levofloxacin. The risk of HSR was 96 times higher in subjects who reported moxifloxacin-induced anaphylaxis and 18 times higher in those reporting immediate reactions compared with clinical entities induced by quinolones other than moxifloxacin and nonimmediate reactions.

CONCLUSIONS

The diagnosis of HSR to quinolones is complex. The use of clinical history is essential as a first step. BAT shows higher sensitivity than STs. DPTs can be useful for finding safe alternative quinolones.

Progress in understanding hypersensitivity reactions to nonsteroidal anti-inflammatory drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs), the medications most commonly used for treating pain and inflammation, are the main triggers of drug hypersensitivity reactions. The latest classification of NSAIDs hypersensitivity by the European Academy of Allergy and Clinical Immunology (EAACI) differentiates between cross-hypersensitivity reactions (CRs), associated with COX-1 inhibition, and selective reactions, associated with immunological mechanisms. Three phenotypes fill into the first group: NSAIDs-exacerbated respiratory disease, NSAIDs-exacerbated cutaneous disease and NSAIDs-induced urticaria/angioedema. Two phenotypes fill into the second one: single-NSAID-induced urticaria/angioedema/anaphylaxis and single-NSAID-induced delayed reactions. Diagnosis of NSAIDs hypersensitivity is hampered by different factors, including the lack of validated in vitro biomarkers and the uselessness of skin tests. The advances achieved over recent years recommend a re-evaluation of the EAACI classification, as it does not consider other phenotypes such as blended reactions (coexistence of cutaneous and respiratory symptoms) or food-dependent NSAID-induced anaphylaxis. In addition, it does not regard the natural evolution of phenotypes and their potential interconversion, the development of tolerance over time or the role of atopy. Here, we address these topics. A state of the art on the underlying mechanisms and on the approaches for biomarkers discovery is also provided, including genetic studies and available information on transcriptomics and metabolomics.

Recent developments and highlights in drug hypersensitivity

Drug hypersensitivity reactions (DHRs) are nowadays the third cause of allergy after rhinitis and asthma with a significant increase in prevalence in both adults and paediatric population with new drugs included as culprit. For this, DHRs represent not only a health problem but also a significant financial burden for affected individuals and health systems. Mislabelling DHRs is showing to be a relevant problem for both, false label of drug allergic and false label of nonallergic. All this reinforces the need to improve accurate diagnostic approaches that allow an appropriate management. Moreover, there is a need for training both, nonallergist stakeholders and patients to improve the reaction identification and therefore decrease the mislabelling. The use of allergy cards has shown to be relevant to avoid the induction of DHRs due to the prescription of wrong medication. Recent developments over the last 2 years and highlights about risk factors, diagnostic approaches, mechanisms involved as well as prevention actions, and management have been reviewed. In these papers, it has been outlined the need for correct diagnosis and de-labelling of patients previously false-reported as allergic, which will improve the management and treatment of patients with DHRs.

Statement of the Spanish Society of Allergology and Clinical Immunology on Provocation Tests With Aspirin/Nonsteroidal Anti-inflammatory Drugs

Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used throughout the world. They are frequently involved in hypersensitivity reactions, which range from local or mild reactions to systemic and severe reactions. Consequently, it is necessary to perform an exhaustive study of patients in order to make an accurate diagnosis, search for safe procedures in the case of severe reactions, and identify alternative treatment options. Various guidelines and protocols address the management of hypersensitivity to NSAIDs, although these vary widely from country to country. The Committees of Asthma, Rhinoconjunctivitis, and Drug Allergy of the Spanish Society of Allergy and Clinical Immunology (SEAIC) propose the present position statement on available options for provocation testing with aspirin/NSAIDs. This document is the fruit of an exhaustive review of current evidence and is based on recent publications addressing the diagnosis of patients with hypersensitivity to NSAIDs and on a consensus-oriented discussion among a group of experts from the SEAIC. The main objective was to draft an easy-toread, practical guideline for health care professionals in specialist areas who assess and manage patients with suspected hypersensitivity to NSAIDs. Furthermore, indications, contraindications, and procedures for oral, bronchial, and nasal provocation tests with aspirin/NSAIDs have been updated.

Bronchial asthma triggered by house dust mites in patients with local allergic rhinitis

BACKGROUND

Over 30% of local allergic rhinitis (LAR) patients self-report bronchial symptoms suggestive of asthma, but the relationship between the allergen exposure and the bronchial symptoms has not been studied.

OBJECTIVE

To investigate whether a bronchial counterpart of LAR exists.

METHODS

Patients were classified by clinical history, skin prick test/serum specific IgE (sIgE), and nasal allergen provocation test (NAPT) into the LAR, allergic rhinitis (AR), and nonallergic rhinitis (NAR) phenotypes. Twenty-eight LAR, 18 AR, and 19 NAR patients self-reporting bronchial symptoms suggestive of asthma and 8 healthy controls (HC) were subjected to a methacholine test (MT) before (Visit 1) and 24 hours after (Visit 3) a bronchial provocation test with Dermatophagoides pteronyssinus (BPT-DP) (Visit 2). Induced sputum and peripheral blood obtained after each MT were analyzed for immune cell populations, tryptase, ECP, and sIgE.

RESULTS

A positive MT was found in 50% of LAR, 83.3% of AR, 57.89% of NAR, and 0% of HC individuals (P = 0.022 AR vs LAR) at V1. BPT-DP was positive in 8 LAR and 15 AR patients (28% vs 83.3%, P < 0.001), with no positive responses in NAR and HC. All BPT-DP+ patients experienced a significant decrease of PC₂₀ at V3 vs V1 (P = 0.016 LAR, P ≤ 0.001 AR). BPT-DP+ patients also showed a significant increase of eosinophils, monocytes, and ECP in induced sputum at V3 compared with V1.

CONCLUSION

The results suggest the existence of a new asthma phenotype (local allergic asthma) defined by absence of systemic atopy and positivity to BPT with allergen.

Update on the Genetic Basis of Drug Hypersensitivity Reactions

Drug hypersensitivity reactions (DHRs) are unpredictable, complex responses to medicines in predisposed individuals. They represent a major health problem owing to the number of patients affected and the severity of the clinical conditions they can induce. In addition to environmental factors, the underlying mechanisms of DHRs are also influenced by genetic factors, although considerable gaps remain in our knowledge. Therefore, further study of the genetics of DHRs is necessary to shed light on their underlying mechanisms. In this manuscript, we provide an update on the genetic basis of the most frequent types of DHRs, including those mediated by immunological and nonimmunological mechanisms. For the first group, we will focus on immediate reactions to β-lactam antibiotics, which are associated mainly with the IgE pathway (IL13, IL4R, LGALS3, and NOD2) and antigen presentation (HLA-DRA), and nonimmediate reactions to allopurinol, anticonvulsants, antibiotics, and antiretrovirals, which are often associated with polymorphisms in the HLA system. For the second group, we will focus on nonsteroidal anti-inflammatory drugs, which are mostly associated with genetic variants in enzymes and receptors from the arachidonic acid pathway (eg, ALOX5, ALOX5AP, PTGDR, and CYSLTR1). The information provided here will be of interest for medical practitioners from a range of disciplines who come across these reactions in their clinical practice, as well as for allergologists.

Identification of Novel Biomarkers for Drug Hypersensitivity After Sequencing of the Promoter Area in 16 Genes of the Vitamin D Pathway and the High-Affinity IgE Receptor

The prevalence of allergic diseases and drug hypersensitivity reactions (DHRs) during recent years is increasing. Both, allergic diseases and DHRs seem to be related to an interplay between environmental factors and genetic susceptibility. In recent years, a large effort in the elucidation of the genetic mechanisms involved in these disorders has been made, mostly based on case-control studies, and typically focusing on isolated SNPs. These studies provide a limited amount of information, which now can be greatly expanded by the complete coverage that Next Generation Sequencing techniques offer. In this study, we analyzed the promoters of sixteen genes related to the Vitamin D pathway and the high-affinity IgE receptor, including FCER1A, MS4A2, FCER1G, VDR, GC, CYP2R1, CYP27A1, CYP27B1, CYP24A1, RXRA, RXRB, RXRG, IL4, IL4R, IL13, and IL13RA1. The study group was composed of patients with allergic rhinitis plus asthma (AR+A), patients with hypersensitivity to beta-lactams (BLs), to NSAIDs including selective hypersensitivity (SH) and cross-reactivity (CR), and healthy controls without antecedents of atopy or adverse drug reactions. We identified 148 gene variations, 43 of which were novel. Multinomial analyses revealed that three SNPs corresponding to the genes FCER1G (rs36233990 and rs2070901), and GC (rs3733359), displayed significant associations and, therefore, were selected for a combined dataset study in a cohort of 2,476 individuals. The strongest association was found with the promoter FCER1G rs36233990 SNP that alters a transcription factor binding site. This SNP was over-represented among AR+A patients and among patients with IgE-mediated diseases, as compared with control individuals or with the rest of patients in this study. Classification models based on the above-mentioned SNPs were able to predict correct clinical group allocations in patients with DHRs, and patients with IgE-mediated DHRs. Our findings reveal gene promoter SNPs that are significant predictors of drug hypersensitivity, thus reinforcing the hypothesis of a genetic predisposition for these diseases.

Eicosanoid mediator profiles in different phenotypes of nonsteroidal anti-inflammatory drug-induced urticaria

BACKGROUND

The role of arachidonic acid metabolites in NSAID-induced hypersensitivity has been studied in depth for NSAID-exacerbated respiratory disease (NERD) and NSAID-exacerbated cutaneous disease (NECD). However, no information is available for NSAID-induced urticarial/angioedema (NIUA), despite it being the most frequent clinical entity induced by NSAID hypersensitivity. We evaluated changes in leukotriene and prostaglandin metabolites for NIUA patients, using patients with NECD and single-NSAID-induced urticaria/angioedema or anaphylaxis (SNIUAA) for comparison.

METHODS

Urine samples were taken from patients with confirmed NSAID-induced urticaria and healthy controls, at baseline and at various time intervals after ASA administration. Eicosanoid measurement was performed using high-performance liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry.

RESULTS

No differences were found between groups at baseline. Following ASA administration, LTE4 and 9α,11β-PGF2 levels were increased in both NIUA and NECD patients compared to baseline, rising initially, before decreasing toward initial levels. In addition, the levels of these metabolites were higher in NIUA and NECD when compared with the SNIUAA and control groups after ASA administration. No changes were found with respect to baseline values for SNIUAA and control groups.

CONCLUSIONS

We present for the first time data regarding the role of COX-1 inhibition in NIUA. Patients with this entity show a similar pattern eicosanoid levels following ASA challenge to those with NECD. Further studies will help ascertain the cell populations involved and the underlying molecular mechanisms.

Spanish survey on follow-up programmes for children born very preterm

AIM

To describe variations in practice between follow-up programmes for very preterm children born at less than 32 weeks' gestation or with very low birth weight of less than 1,500 g.

METHODS

A survey on follow-up practices was electronically distributed to level II and III units among hospitals of the Spanish National Health Service in 2016. The survey included 70 questions covering issues such as follow-up organisation and resources, routine assessments, relationships with other services and families, information management and training.

RESULTS

The response rate was 91.5% (141/154). Among respondents, 70.9% (100/141) reported that they do provide follow-up and 42% do so up to six years of age. Routine neurological and ophthalmological follow-up is not performed in 60% and 37% of hospitals, respectively, and a second hearing assessment is not given in 62%. Just 38% of units have psychologist. In 41% of hospitals, training in follow-up skills is not included in Paediatric Residency training programme.

CONCLUSION

Although Spain has a nationwide health system that provides universal health coverage, we found that follow-up care for children born very preterm/very low birth weight is not equitable. Nearly half of paediatric residents receive no training in follow-up for this high-risk population.

Safety and reproducibility of nasal allergen challenge

BACKGROUND

The nasal allergen challenge (NAC) is a useful tool for the diagnosis of allergic rhinitis (AR) and local allergic rhinitis (LAR) and might serve to design and monitor allergen immunotherapy. Nevertheless, data about its safety and reproducibility are scarce.

OBJECTIVE

To investigate the safety and reproducibility of NAC in pediatric and adult rhinitis patients with/without asthmatic symptoms, and in healthy controls.

METHODS

A retrospective evaluation of the NACs conducted in our Unit for 2005-2017 and monitored by acoustic rhinometry and nasal-ocular symptoms was performed to analyze the safety of two methods for allergen application (metered spray & micropipette) and NAC protocols (NAC with single or multiple allergens/session [NAC-S & NAC-M]). The adverse events (AEs), spirometry values, and rescue medication required for AE were recorded. The reproducibility was examined by a prospective analysis of three repeated NAC-S performed at 1-2-month interval in AR, LAR and nonallergic rhinitis patients, and in healthy controls.

RESULTS

A total of 11 499 NACs were performed in 518 children and 5830 adults. Only four local AE occurred, and 99.97% of NACs were well tolerated. The reproducibility and positive and negative predictive values of three consecutive NAC-S performed in 710 subjects were 97.32%, 100%, and 92.91%, respectively. There were no false-positive results in the 710 analyzed subjects. Safety and reproducibility were comparable between the methods of allergen application and the rhinitis phenotypes.

CONCLUSION

The NAC is a safe and highly reproducible diagnostic test ready to be used in the clinical practice in both children and adults with or without asthma.