Flow-based basophil activation test in immediate drug hypersensitivity. An EAACI task force position paper.

Diagnosing immediate drug hypersensitivity reactions (IDHRs) can pose a significant challenge and there is an urgent need for safe and reliable tests. Evidence has emerged that the basophil activation test (BAT), an in vitro assay that mirrors the in vivo response, can be a complementary test for many drugs. In this position paper, members of Task Force (TF) "Basophil activation test in the evaluation of Drug Hypersensitivity Reactions" from the European Academy of Allergy and Clinical Immunology (EAACI) present the data from a survey about the use and utility of BAT in IDHRs in Europe. The survey results indicate that there is a great interest for using BAT especially for diagnosing IDHRs. However, there are still main needs, mainly in the standardization of the protocols. Subsequently consensus-based recommendations were formulated for: (i) Technical aspects of BAT in IDHRs including type of sample, management of drugs, flow cytometry protocols, interpretation of the results; and (ii) Drug-specific aspects that should be taken into account when performing BAT in relation to betalactams, neuromuscular blocking agents, fluoroquinolones, chlorhexidine, opioids, radio contrast media, chemotherapeutics, biological agents, nonsteroidal anti-inflammatory drugs, COVID vaccine, and excipients. Moreover, aspects in the evaluation of pediatric population have also been considered. All this indicates that BAT offers the clinician and laboratory a complementary tool for a safe diagnostic for IDHRs, although its place in the diagnostic algorithm depends on the drug class and patient population (phenotype, geography, and age). The standardization of BAT is important for generalizing this method beyond the individual laboratory.

Immunological mechanisms involved in the human response to a dog dander allergoid.

BACKGROUND: Dog allergens are a common cause of allergic sensitisation and trigger respiratory symptoms worldwide. However, clinical evidence regarding dog immunotherapy is limited. Therefore, the aim of this study was to analyse the immunomodulatory properties of a new allergoid from dog dander, thereby deepening the understanding of the molecular mechanisms involved in the reestablishment of the tolerogenic response. METHODS: Three independent batches of dog dander native and allergoid allergen extracts were manufactured and characterised. Allergenic profiles were analysed by the identification of all dog allergens and quantification of the major allergens Can f 1 and Can f 5. The allergenicity profile of the allergoid was studied using biological potency and basophil activation tests. In vitro immunomodulatory parameters was evaluated as the capacity of the allergoid to induce IgG antibodies that block IgE binding to the allergen and cytokine promotion (IFN-γ, IL-4, IL-6, IL-10, IL-13, and TNF-α) in PBMCs from allergic donors. RESULTS: The presence of all dog allergens, including Can f 1 and Can f 5, was confirmed in both types of extracts. The new allergoid showed a low IgE binding capacity, which significantly affected the activation of effector cells, such as basophils. The IgG antibodies induced by the allergoid in rabbits blocked human IgE binding epitopes on the dog native extract and induced Th1 and Treg responses by increasing IFN-γ and IL-10 levels in PBMCs from allergic donors. CONCLUSION: This new dog dander allergoid containing Can f 1 and Can f 5 showed a low capacity to bind IgE and to activate basophils in dog allergic patients. Furthermore, it showed potent activation of Th1 mediators and induction of tolerance through Treg activation. This allergoid could offer a safer profile than the native extract and could be an effective immunotherapy treatment for dog allergic patients.

Polymorphisms in eicosanoid-related biosynthesis enzymes associated with acute urticaria/angioedema induced by nonsteroidal anti-inflammatory drug hypersensitivity.

BACKGROUND: Nonsteroidal anti-inflammatory drugs (NSAIDs) are the main triggers of drug hypersensitivity, with NSAID-induced acute urticaria/angioedema (NIUA) the most frequent phenotype. NSAID hypersensitivity is caused by cyclooxygenase 1 inhibition, which leads to an imbalance in prostaglandin (PG) and cysteinyl leukotriene (CysLT) synthesis. As only susceptible individuals develop NSAID hypersensitivity, genetic factors are believed to be involved; however, no study has assessed the overall genetic variability of key enzymes in PG and CysLT synthesis in NSAID hypersensitivity. OBJECTIVES: To evaluate simultaneously variants in the main genes involved in PG and CysLT biosynthesis in NIUA. METHODS: Two independent cohorts of patients were recruited in Spain, alongside NSAID-tolerant controls. The discovery cohort included only patients with NIUA; the replication cohort included patients with NSAID-exacerbated respiratory disease (NERD). A set of tagging single-nucleotide polymorphisms (tagSNPs) in PTGS1, PTGS2, ALOX5 and LTC4S was genotyped using mass spectrometry coupled with endpoint polymerase chain reaction. RESULTS: The study included 1272 individuals. Thirty-five tagSNPs were successfully genotyped in the discovery cohort, with three being significantly associated after Bonferroni correction (rs10306194 and rs1330344 in PTGS1; rs28395868 in ALOX5). These polymorphisms were genotyped in the replication cohort: rs10306194 and rs28395868 remained associated with NIUA, and rs28395868 was marginally associated with NERD. Odds ratios (ORs) in the combined analysis (discovery and replication NIUA populations) were 1·7 for rs10306194 [95% confidence interval (CI) 1·34-2·14; Pcorrected = 2·83 × 10-4 ) and 2·19 for rs28395868 (95% CI 1·43-3·36; Pcorrected = 0·002). CONCLUSIONS: Variants of PTGS1 and ALOX5 may play a role in NIUA and NERD, supporting the proposed mechanisms of NSAID-hypersensitivity and shedding light on their genetic basis.

Clinical Approach to Mast Cell Activation Syndrome: A Practical Overview.

The diagnosis of mast cell activation syndrome (MCAS) is defined by 3 criteria: (1) typical clinical signs and symptoms of acute, recurrent (episodic), and systemic mast cell activation (MCA); (2) increase in tryptase level to >20% + 2 ng/mL within 1-4 hours after onset of the acute crisis; and (3) response of MCA symptoms to antimediator therapy. Classification of MCAS requires highly sensitive and specific methodological approaches for the assessment of clonal bone marrow mast cells at low frequencies. The Spanish Network on Mastocytosis score has been used successfully as a predictive model for selecting MCAS candidates for bone marrow studies based on a high probability of an underlying clonal mast cell disorder. In this article, we propose a diagnostic algorithm and focus on the practical evaluation and management of patients with suspected MCAS.

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.

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. (AU)

Las Redes Temáticas de Investigación Cooperativa en Salud (RETICS) son unas estructuras organizativas promovidas por el Instituto de Salud Carlos III del Ministerio de e Sanidad, Consumo y Bienestar Social con el objetivo de llevar a cabo proyectos de investigación colaborativos que aborden desafíos de interés general para la sociedad en el campo de la salud. La RETICS de Asma, Reacciones Adversas a Fármacos y Alérgicas (ARADyAL) comenzó en 2016 y fue financiada por un periodo de 5 años (2017-2021). ARADyAL integra la investigación básica y clínica en diferentes áreas de conocimiento, alergia, inmunología, genética, nanomedicina, farmacología y química, con especial interés en la investigación de nuevos biomarcadores, y el diseño y evaluación de nuevas estrategias de intervención para pacientes alérgicos con fenotipos graves. El consorcio está compuesto por 28 grupos de toda España, que incluyen 171 investigadores clínicos y básicos: 17 grupos clínicos que cubren a más de 10.000.000 de pacientes de todas las edades y de áreas tanto urbanas como rurales; 11 grupos básicos que desarrollan sus actividades principalmente en universidades e institutos de investigación. ARADyAL propone un programa de investigación organizado en tres áreas diferentes centradas en la medicina de precisión: Programa 1. Mecanismos y predicción de reacciones adversas a medicamentos y enfermedades alérgicas; Programa 2. Hacia un diagnóstico preciso de enfermedades alérgicas; y Programa 3. Predicción de intervenciones en enfermedades alérgicas. Además, hay un programa transversal dedicado a la formación. La red cuenta con un Comité de Dirección y un Comité Científico Asesor Externo, que asesoran a la coordinadora de la red la cual tiene experiencia reconocida en el campo. ARADyAL es un punto de encuentro único para médicos y científicos básicos que ya están trabajando en alergias.

Clinical Approach to Mast Cell ActivationSyndrome: A Practical Overview

The diagnosis of mast cell activation syndrome (MCAS) is defined by 3 criteria: (1) typical clinical signs and symptoms of acute, recurrent (episodic), and systemic mast cell activation (MCA); (2) increase in tryptase level to >20% + 2 ng/mL within 1-4 hours after onset of the acute crisis; and (3) response of MCA symptoms to antimediator therapy. Classification of MCAS requires highly sensitive and specific methodological approaches for the assessment of clonal bone marrow mast cells at low frequencies. The Spanish Network on Mastocytosis score has been used successfully as a predictive model for selecting MCAS candidates for bone marrow studies based on a high probability of an underlying clonal mast cell disorder. In this article, we propose a diagnostic algorithm and focus on the practical evaluation and management of patients with suspected MCAS (AU)

El diagnóstico de síndrome de activación mastocitaria (SAM) se basa en 3 criterios: 1) signos y síntomas específicos de activación mastocitaria aguda, recurrente y sistémica, 2) aumento de los valores de triptasa en un 20% + 2 ng/ml sobre el valor basal de cada individuo en el periodo comprendido entre 1-4 horas desde el inicio del cuadro agudo, y 3) resolución de los síntomas con tratamiento antimediador. Para realizar el diagnóstico de SAM, es preciso emplear métodos diagnósticos altamente sensibles y específicos capaces de detectar bajas cantidades de mastocitos en la médula ósea. El modelo predictivo de la Red Española de Mastocitosis (REMA score) resulta útil para identificar a los pacientes con mayor probabilidad de padecer una patología mastocitaria clonal y que, por tanto, requieren que se nealice un estudio de médula ósea en el proceso diagnóstico. En este artículo, proponemos un algoritmo diagnóstico para SAM y abordamos el manejo de estos pacientes desde un punto de vista práctico en la consulta alergológica (AU)

Local allergic rhinitis: Implications for management.

A significant proportion of rhinitis patients without systemic IgE-sensitisation tested by skin prick test and serum allergen-specific IgE (sIgE) display nasal reactivity upon nasal allergen provocation test (NAPT). This disease phenotype has been termed local allergic rhinitis (LAR). LAR is an underdiagnosed entity affecting children and adults from different parts of the world, with moderate-to-severe symptoms, impairment of quality of life and rapid progression to symptom worsening. LAR is a stable phenotype and not merely an initial state of AR. Allergic rhinitis and LAR share many clinical features including a positive NAPT response, markers of type 2 nasal inflammation including sIgE in nasal secretions and a significant rate of asthma development. LAR should be considered as a differential diagnosis in those subjects of any age with symptoms suggestive of AR but no evidence of systemic atopy. Although LAR pathophysiology is partially unknown, in some patients sIgE can be demonstrated directly in the nasal secretions and/or indirectly via positive responses in basophil activation test (BAT). LAR can coexist with other rhinitis phenotypes, especially AR. The diagnosis currently relies on the positivity of NAPT to a single or multiple allergens. NAPT has high sensitivity, specificity and reproducibility, and it is considered the gold standard. BAT and the measurement of nasal sIgE can also contribute to LAR diagnosis. LAR patients benefit from the same therapeutic strategies than AR individuals, including the avoidance of allergen exposure and the pharmacotherapy. Moreover, several recent studies support the effectiveness and safety of allergen immunotherapy for LAR, which opens a window of treatment opportunity in these patients.

Accuracy of the Diagnosis of Allergic Reactions in the Emergency Department.

BACKGROUND AND OBJECTIVE: Suspicion of an acute allergic reaction is a common reason for attending the emergency department (ED). However, there are few comparisons between the initial diagnosis of suspected allergic reaction made in the ED with the definitive diagnosis made subsequently in the allergy department (AD). Objective: To compare details of the initial diagnosis made in the ED relating to allergy with the final diagnosis made in the AD. METHODS: Patients attending the ED of 2 hospitals with suspected allergic reactions were prospectively enrolled based on key words. A certified allergy specialist reviewed the ED records of these patients and, if these were suggestive of an allergic reaction, the patients were scheduled for further evaluation at the allergy clinic. RESULTS: In total, 2000 patients were enrolled between April 2013 and October 2015. Of these, 1333 passed the initial assessment and underwent further evaluation. Of the 1333 patients, 528 underwent an allergological study, and 206 were confirmed as being allergic. With respect to drug allergy, nonsteroidal anti-inflammatory drugs were the most common triggers, followed by ß-lactams; in food allergy, plant-based foods were the most common. Only 16.4% of patients confirmed as having anaphylaxis in the AD were initially diagnosed with the condition in the ED. CONCLUSION: Of the 528 patients who finally underwent the full allergological study, fewer than half were confirmed as allergic. Moreover, anaphylaxis appears to be underdiagnosed in the ED. Better communication between the ED and the AD is necessary to improve the diagnosis and management of these patients.

Accuracy of the diagnosis of allergic reactions in the emergency department

Background: Suspicion of an acute allergic reaction is a common reason for attending the emergency department (ED). However, there are few comparisons between the initial diagnosis of suspected allergic reaction made in the ED with the definitive diagnosis made subsequently in the allergy department (AD).Objective: To compare details of the initial diagnosis made in the ED relating to allergy with the final diagnosis made in the AD. Methods: Patients attending the ED of 2 hospitals with suspected allergic reactions were prospectively enrolled based on key words. A certified allergy specialist reviewed the ED records of these patients and, if these were suggestive of an allergic reaction, the patients were scheduled for further evaluation at the allergy clinic. Results: In total, 2000 patients were enrolled between April 2013 and October 2015. Of these, 1333 passed the initial assessment and underwent further evaluation. Of the 1333 patients, 528 underwent an allergological study, and 206 were confirmed as being allergic. With respect to drug allergy, nonsteroidal anti-inflammatory drugs were the most common triggers, followed by ß-lactams; in food allergy, plant-based foods were the most common. Only 16.4% of patients confirmed as having anaphylaxis in the AD were initially diagnosed with the condition in the ED. Conclusion: Of the 528 patients who finally underwent the full allergological study, fewer than half were confirmed as allergic. Moreover, anaphylaxis appears to be underdiagnosed in the ED. Better communication between the ED and the AD is necessary to improve the diagnosis and management of these patients

Antecedentes: La sospecha de una reacción alérgica aguda es un motivo frecuente de consulta en urgencias. Sin embargo, hay pocos trabajos que comparen el diagnóstico inicial realizado en las unidades de urgencias con el diagnóstico definitivo realizado en las unidades de alergia. Objetivo: Analizar en detalle la sospecha diagnóstica inicial dada en urgencias con el diagnóstico definitivo en las consultas de alergia. Métodos: Estudio prospectivo, que consistió en la selección, en base a palabras claves, de pacientes con sospecha de reacción alérgica. En la fase de screening, se seleccionaron los pacientes en base a las palabras claves, finalmente aquellos pacientes que presentan reacción sugestiva de alergia se seleccionaron para evaluación final. Resultados: Se revisaron 2.000 pacientes entre abril de 2013 y octubre de 2015, de los cuales 1.333 se seleccionaron para la evaluación. Finalmente, 528 se sometieron a un estudio alergológico y 206 se confirmaron como alérgicos. Con respecto a las reacciones por fármacos, los AINE y ß-lactámicos fueron los mayormente implicados; en relación con los alimentos, los de origen vegetal fueron los más frecuentes. Sólo el 16,4% de los pacientes con anafilaxia confirmada tras el estudio de alergia, fueron diagnosticados inicialmente en urgencias. Conclusión: Sólo la mitad de los pacientes que finalizaron en estudio fueron confirmados como alérgicos. Un dato importante es el infradiagnóstico de la anafilaxia en las urgencias. Por ello pensamos que es necesaria una mejor comunicación entre las unidades de urgencias y alergia para mejorar el manejo clínico y terapéutico de estos pacientes

Practical Guidelines for Perioperative Hypersensitivity Reactions.

Perioperative hypersensitivity reactions constitute a first-line problem for anesthesiologists and allergists. Therefore, hospitals should have a consensus protocol for the diagnosis and management of these reactions. However, this kind of protocol is not present in many hospitals, leading to problems with treatment, reporting of incidents, and subsequent etiological diagnosis. In this document, we present a systematic review of the available scientific evidence and provide general guidelines for the management of acute episodes and for referral of patients with perioperative hypersensitivity reactions to allergy units. Members of the Drug Allergy Committee of the Spanish Society of Allergy and Clinical Immunology (SEAIC) have created this document in collaboration with members of the Spanish Anesthesia Society (SEDAR). A practical algorithm is proposed for the etiologic diagnosis, and recommendations are provided for the management of hypersensitive patients.

Specific immunotherapy in local allergic rhinitis: A randomized, double-blind placebo-controlled trial with Phleum pratense subcutaneous allergen immunotherapy.

BACKGROUND: Allergen immunotherapy has been shown to be an effective treatment for local allergic rhinitis (LAR) to house dust mites. Studies with pollen allergen immunotherapy are limited to observational studies. The aim of this study was to evaluate the clinical efficacy and safety of Phleum pratense subcutaneous immunotherapy (Phl-SCIT) in LAR. METHODS: In a randomized double-blind placebo-controlled study, 56 patients with moderate-severe LAR to grass pollen received Phl-SCIT with a depigmented polymerized pollen vaccine or placebo for the first year, and Phl-SCIT the second one. The blind was maintained throughout the study. Primary outcome was combined symptom medication score (CSMS) during grass pollen season (GPS). Secondary clinical outcomes included organ-specific symptoms, medication-free days, rhinitis severity and asthma control. Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), nasal allergen provocation test (NAPT), skin testing, serum levels of specific IgG4 and specific IgE and safety were also evaluated. RESULTS: Subcutaneous immunotherapy (SCIT) had a short-term and sustained effect with significant improvements of all primary and secondary clinical outcomes and RQLQ score. SCIT significantly increased serum sIgG4 levels and allergen tolerance, from the 6th to 24th months of treatment. At the end of the study, 83% of patients treated with ≥6 months of SCIT tolerated a concentration of P. pratense over 50 times higher than baseline, and 56% gave a negative NAPT. SCIT was well tolerated; six mild local reactions occurred, and there were no serious adverse events related to the study medication. CONCLUSIONS: Subcutaneous immunotherapy with depigmented polymerized allergen extracts is a safe and clinically effective treatment for LAR to P. pratense.

Local allergic rhinitis is an independent rhinitis phenotype: The results of a 10-year follow-up study.

BACKGROUND: The knowledge about the natural history of local allergic rhinitis (LAR) is limited. One unmet question is to demonstrate whether LAR should be considered the first step in the development of allergic rhinitis (AR) or an independent phenotype. The aim of this study was to prospectively evaluate the natural history of a population with LAR, the potential conversion to AR with systemic atopy and the development of asthma during 10 years. METHODS: This is the second phase of a 10-year follow-up study of a cohort of 176 patients with LAR of recent onset and 115 age- and sex-matched healthy controls prospectively evaluated from 2005 to 2016. Clinical-demographic questionnaire, spirometry, skin prick test and specific IgE were evaluated yearly. Nasal allergen provocation tests (NAPT) with Dermatophagoides pteronyssinus, Alternaria alternata, Olea europaea and grass pollen were performed at baseline, and after 5 and 10 years. RESULTS: After 10-year LAR, patients experienced a significant and clinically relevant worsening of the rhinitis, with increase in emergency assistance, development of asthma, loss of allergen tolerance and impairment of the quality of life. This worsening became significant after 5 years and progressed throughout 10 years. A similar rate of development of AR with systemic atopy was detected in patients and controls (9.7% vs 7.8%, log-rank P=.623). In 5 patients, conversion to systemic atopy occurred >10 years (3%). CONCLUSIONS: LAR is a well-differentiated clinical entity with a low rate of development of systemic atopy, a natural evolution towards worsening and a risk factor for suffering asthma.

Practical guidelines for perioperative hypersensitivity reactions

Perioperative hypersensitivity reactions constitute a first-line problem for anesthesiologists and allergists. Therefore, hospitals should have a consensus protocol for the diagnosis and management of these reactions. However, this kind of protocol is not present in many hospitals, leading to problems with treatment, reporting of incidents, and subsequent etiological diagnosis. In this document, we present a systematic review of the available scientific evidence and provide general guidelines for the management of acute episodes and for referral of patients with perioperative hypersensitivity reactions to allergy units. Members of the Drug Allergy Committee of the Spanish Society of Allergy and Clinical Immunology (SEAIC) have created this document in collaboration with members of the Spanish Anesthesia Society (SEDAR). A practical algorithm is proposed for the etiologic diagnosis, and recommendations are provided for the management of hypersensitive patients

Las reacciones de hipersensibilidad perioperatorias constituyen un problema de primera línea para los anestesiólogos y alergólogos, por lo que es recomendable que los hospitales tengan un protocolo de consenso para el diagnóstico y el tratamiento de estas reacciones. Sin embargo, este tipo de protocolos no está presente en muchos hospitales, lo que conlleva problemas en el tratamiento, la comunicación de incidentes y el posterior diagnóstico etiológico. Este documento ha sido creado por miembros del Comité de Alergia a Medicamentos de la Sociedad Española de Alergia e Inmunología Clínica (SEAIC) en colaboración con miembros de la Sociedad Española de Anestesia (SEDAR). Se ha realizado una revisión sistemática de la evidencia científica disponible y se proporcionan pautas generales para el manejo de episodios agudos y para la derivación de pacientes con reacciones de hipersensibilidad perioperatoria a los Servicios de Alergología. Se propone un algoritmo práctico para el diagnóstico etiológico y se brindan recomendaciones para el manejo de pacientes con reacciones alérgicas perioperatorias

Dermatophagoides pteronyssinus immunotherapy changes the T-regulatory cell activity.

Subcutaneous specific immunotherapy (SCIT) has been shown to modify the Dermatophagoides pteronissinus (DP) allergic response, characterized by generation of Treg cells. However, studies have reported no changes in the proportion of Treg cells after immunotherapy, indicating that the effects may be due to modifications in their regulatory activities. We aimed to determine whether Tregs generated by DP-SCIT can switch the allergic response to tolerant and study the involvement of suppressive cytokines on it. Twenty-four DP-allergic rhinitis patients were recruited, 16 treated with DP-SCIT and 8 untreated. Treg and T effector cells were isolated before and after DP-SCIT, and cocultured in different combinations with α-IL-10, α-TGF-ß blocking antibodies and nDer p 1. Treg cells after DP-SCIT increased Th1 and decreased Th2 and Th9 proliferation. Similarly, they increased IL-10 and decreased IL-4 and IL-9-producing cells. α-IL-10 affected the activity of Treg cells obtained after DP-SCIT only. Finally, DP-specific IgG4 levels, Treg percentage and IL-10 production were correlated after DP-SCIT. These results demonstrate that DP-SCIT induces Treg cells with different suppressive activities. These changes could be mediated by IL-10 production and appear to play an important role in the induction of the tolerance response leading to a clinical improvement of symptoms.

Basophil Histamine Release Induced by Amoxicilloyl-poly-L-lysine Compared With Amoxicillin in Patients With IgE-Mediated Allergic Reactions to Amoxicillin.

BACKGROUND: Amoxicillin (AX) is the ß-lactam most often involved in IgE-mediated reactions. Diagnosis is based mainly on skin testing, although sensitivity is not optimal. We produced a new AX derivative, amoxicilloyl-poly-L-lysine (APL), and analyzed its recognition of IgE using the passive histamine release test (pHRT). METHODS: The study population comprised patients (n=19) with confirmed AX allergy and specific IgE to AX and controls (n=10) with good tolerance to AX. pHRT was performed using "IgE-stripped" blood from a single donor that was sensitized in vitro by patient sera and incubated with AX or APL. Histamine release was determined and expressed as nanograms of histamine released per milliliter of blood. RESULTS: The clinical symptoms were anaphylaxis (n=9), urticaria (n=7), erythema (n=2), and nondefined immediate reactions (n=1). The median (IQR) time interval between reaction and study was 90 (60-240) days and between drug intake and development of symptoms 24 (10-60) minutes. The median sIgE level was 3.37 (0.95-5.89) kUA/L. The sensitivity of pHRT to APL was 79% and the specificity 100%, which were higher than data obtained with pHRT to AX (63% sensitivity and 90% specificity). There was a positive correlation between maximal histamine release levels obtained with AX and APL (r=0.63). CONCLUSIONS: In patients with immediate hypersensitivity reactions to AX, APL showed higher sensitivity and specificity than the culprit drug, AX, when tested in vitro by pHRT. This indicates that APL can improve the in vitro diagnostic accuracy of allergic reactions to AX. Further assessment of skin testing is necessary.