LAD2 mast cell activation test associates with the reaction severity and diagnoses BAT nonresponders in Hymenoptera venom allergy.

BACKGROUND AND OBJECTIVE: The usefulness of the mast cell activation test (MAT) in diagnosing patients with uninterpretable basophil activation test (BAT) caused by nonresponding basophils has not yet been addressed. It should be further evaluated if the results of MAT are associated with the severity of the allergic reaction. METHODS: We recruited 39 Hymenoptera venom allergic (HVA) patients, 22 non-sensitized controls, and 37 BAT nonresponding HVA patients. Specific IgE levels for honey bee venom (HBV), yellow jacket venom (YJV) and total IgEs were quantified using the Immulite system. BAT and MAT with LAD2 cells in response to HBV and YJV were performed. RESULTS: We first optimized the susceptibility of LAD2 cells to IgE-mediated degranulation in HVA and showed that prestimulation with IL-33 and IL-6 significantly increased the LAD2 cells´ responsiveness to allergen stimulation (P<0.01). LAD2 MAT results correlated with BAT results, and patients with severe sting reactions (Mueller grades IV or III) had a median 2-fold higher LAD2 MAT than the patients with nonsevere sting reactions (Mueller grades II, I or LLR) (P<0.05). Further, LAD2 MAT provided conclusive results in 54.1% (20 of 37) of HVA patients with nonresponding basophils in the BAT. CONCLUSION: The LAD2 MAT represents a new diagnostic tool for HVA patients with nonresponding basophils. Further, LAD2 MAT can identify patients at risk of severe sting reactions and thus can help guide recommendations for venom immunotherapy and improve the management of patients with HVA.

Quantitative, Absolute Count-Based T-Cell Analysis of CD69 Upregulation as a New Methodology for In Vitro Diagnosis of Delayed-Type Hypersensitivity Reaction to Nickel.

BACKGROUND: T cells play a major role in delayed-type hypersensitivity reactions. Their reactivity can be assessed by measuring the upregulation of the activation marker CD69, followed by assessment of proliferation and cytokine production. The aim of our study was to develop a novel, whole blood-based, quantitative, absolute count activation index (AI) for analysis of CD69 upregulation in various subsets of T cells in nickel-hypersensitive patients and compare it with previously reported approaches. METHODS: The study population comprised 10 patients with nickel allergy and 9 healthy controls. CD69 expression of CD3+, CD3+CD4+, and CD3+CD8+ T cells in heparinized blood was determined with flow cytometry after incubation with nickel sulfate for 48 hours. The absolute count of CD69+ cells was determined using microbeads. Production of the cytokines IL-2, IL-5, IL-13, and IFN-γ was determined after stimulation of peripheral blood mononuclear cells with nickel sulfate for 48 hours. RESULTS: We showed absolute AI to be the most sensitive approach. The index was calculated as the ratio of the absolute count of nickel-stimulated CD69-positive T cells to the absolute count of CD69-positive T cells in nonstimulated blood. This novel quantitative approach was more discriminative than previously reported approaches in which the T-cell CD69 percentage AI and cytokine production are measured. CONCLUSIONS: Our results demonstrated that measuring the absolute CD69 AI is a novel and accurate approach for quantification of antigen-specific T cells in the blood of patients with hypersensitivity reactions to nickel. This approach may be useful for better in vitro assessment of patients with delayed-type hypersensitivity reactions.

Quantitative, absolute count-based T-Cell analysis of CD69 upregulation as a new methodology for in vitro diagnosis of delayed-type hypersensitivity reaction to nickel

BACKGROUND: T cells play a major role in delayed-type hypersensitivity reactions. Their reactivity can be assessed by measuring the upregulation of the activation marker CD69, followed by assessment of proliferation and cytokine production. The aim of our study was to develop a novel, whole blood-based, quantitative, absolute count activation index (AI) for analysis of CD69 upregulation in various subsets of T cells in nickel-hypersensitive patients and compare it with previously reported approaches. METHODS: The study population comprised 10 patients with nickel allergy and 9 healthy controls. CD69 expression of CD3+, CD3+CD4+, and CD3+CD8+ T cells in heparinized blood was determined with flow cytometry after incubation with nickel sulfate for 48 hours. The absolute count of CD69+ cells was determined using microbeads. Production of the cytokines IL-2, IL-5, IL-13, and IFN-γ was determined after stimulation of peripheral blood mononuclear cells with nickel sulfate for 48 hours. RESULTS: We showed absolute AI to be the most sensitive approach. The index was calculated as the ratio of the absolute count of nickel-stimulated CD69-positive T cells to the absolute count of CD69-positive T cells in nonstimulated blood. This novel quantitative approach was more discriminative than previously reported approaches in which the T-cell CD69 percentage AI and cytokine production are measured. CONCLUSIONS: Our results demonstrated that measuring the absolute CD69 AI is a novel and accurate approach for quantification of antigen-specific T cells in the blood of patients with hypersensitivity reactions to nickel. This approach may be useful for better in vitro assessment of patients with delayed-type hypersensitivity reactions

ANTECEDENTES: Los linfocitos T juegan un papel importante en las reacciones de hipersensibilidad de tipo retardado. Su actividad puede evaluarse midiendo la expresión del marcador de activación CD69, seguido de la proliferación y la producción de citocinas. El objetivo de nuestro estudio ha sido el desarrollar un novedoso análisis cuantitativo del índice de activación absoluto (AI) en sangre completa de la expresión de CD69, en diferentes subconjuntos de linfocitos T, en pacientes con hipersensibilidad al níquel, y compararlo con los métodos existentes. MÉTODOS: Se estudiaron diez pacientes con alergia al níquel y nueve controles sanos. La expresión de CD69 de los linfocitos T CD3+, CD3+CD4+ y CD3+ CD8+ en sangre heparinizada se determinó con citometría de flujo, después de una incubación con sulfato de níquel durante 48 h. El recuento absoluto de células CD69+ se determinó con microesferas. La producción de las citocinas IL-2, IL-5, IL-13 e IFN-γ se cuantificó después de la estimulación de células mononucleares periféricas, durante 48 h, con sulfato de níquel. RESULTADOS: Se demuestra que la determinación del índice AI absoluto es la metodología más sensible. Se calculó como la relación entre el recuento absoluto de linfocitos T CD69-positivos estimulados con níquel y el recuento absoluto de linfocitos T CD69-positivos en sangre no estimulada. Este nuevo enfoque cuantitativo fue más discriminativo que los enfoques publicados previamente en los que se midió el porcentaje de CD69 de linfocitos T y la producción de citocinas. CONCLUSIONES: Nuestros resultados demostraron que la medición del AI absoluto de CD69 es un enfoque nuevo y preciso para cuantificar los linfocitos T específicos de antígeno en la sangre de pacientes con reacciones de hipersensibilidad al níquel. Este enfoque puede ser útil para una mejor evaluación in vitro de los pacientes con reacciones de hipersensibilidad de tipo retardado

Important and specific role for basophils in acute allergic reactions.

IgE-mediated allergic reactions involve the activation of effector cells, predominantly through the high-affinity IgE receptor (FcεRI) on mast cells and basophils. Although the mast cell is considered the major effector cell during acute allergic reactions, more recent studies indicate a potentially important and specific role for basophils and their migration which occurs rapidly upon allergen challenge in humans undergoing anaphylaxis. We review the evidence for a role of basophils in contributing to clinical symptoms of anaphylaxis and discuss the possibility that basophil trafficking during anaphylaxis might be a pathogenic (to target organs) or protective (preventing degranulation in circulation) response. Finally, we examine the potential role of basophils in asthma exacerbations. Understanding the factors that regulate basophil trafficking and activation might lead to new diagnostic and therapeutic strategies in anaphylaxis and asthma.

GLCCI1 Polymorphism rs37973 and Response to Treatment of Asthma With Inhaled Corticosteroids.

BACKGROUND: The response to asthma treatment is highly variable, and having pharmacogenetic markers that predict response to treatment would bring us one step closer to personalized treatment. Genome-wide association studies have shown that polymorphisms in GLCCI1 could be associated with the response to inhaled corticosteroids (ICSs) in asthma patients. MATERIAL AND METHODS: We genotyped rs37973 in GLCCI1 in 208 adult asthma patients treated with ICSs. The percentage change in FEV1, % predicted was analyzed after short-term treatment (3 months) and long-term treatment (at least 3 years). Treatment was defined as successful when FEV1 decreased by <30 mL/year. RESULTS: After 3 months of treatment, FEV1, % predicted was higher in patients with the GG genotype than in patients with the AG+AA genotype, and this genotype-dependent difference was only evident in nonsmokers. Similar results were found in nonsmokers and patients with atopy after at least 3 years of treatment, when all patients were analyzed. Even though no differences were observed for success of treatment (good vs poor response) when the whole group of patients was analyzed, genotype-dependent treatment success was highly influenced by smoking and atopy. The GG genotype was overrepresented in nonsmokers and patients with atopy and a good response. CONCLUSIONS: rs37973 was associated with response to short- and long-term treatment; however, smoking and atopy had a considerable effect on pharmacogenetic association. Furthermore, in contrast with findings from genome-wide association studies, we found the GG genotype to be associated with better treatment response.

SPINK5 is associated with early-onset and CHI3L1 with late-onset atopic dermatitis.

We have recently showed that filaggrin (FLG) mutations are associated only with early-onset of AD, but not with late-onset of AD. Consequently, other susceptibility genes should receive attention, especially in patients with late-onset of AD. Our aim was to assess the associations between development of AD and the polymorphisms rs2303067 in SPINK5 and rs490928 in CHI3L1. A study population of 241 AD patients and 164 healthy controls was genotyped for two polymorphisms (rs2303067 in SPINK5 and rs490928 in CHI3L1). Rs2303067 in SPINK5 was significantly associated with early-onset AD (≤8 years: p = .003; OR = 2.57) and was characterized by the need for hospitalization (p = .006; OR = 2.76), prolonged duration (≥10 years; p = .008; OR = 2.32) and more body parts affected (p = .015; OR = 2.01). In contrast, rs490928 in CHI3L1 was associated with late-onset AD (>8 years: p = .048; OR = 1.65) and was characterized by no need for hospitalization (p = .049; OR = 1.59), shorter duration (<10 years; p = .017; OR = 1.94) and fewer body parts affected (p = .049; OR = 1.75). Our results confirmed that different AD phenotypes, specifically early- and late-onset AD, have different genetic backgrounds. Early-onset AD was associated with rs2303067 in SPINK5, which is involved in skin barrier functioning, and late-onset was associated with rs4950928 in CHI3L1, which is involved in the immune response. Future studies should examine the early- versus late-onset subgrouping more closely.

EAACI Molecular Allergology User's Guide.

The availability of allergen molecules ('components') from several protein families has advanced our understanding of immunoglobulin E (IgE)-mediated responses and enabled 'component-resolved diagnosis' (CRD). The European Academy of Allergy and Clinical Immunology (EAACI) Molecular Allergology User's Guide (MAUG) provides comprehensive information on important allergens and describes the diagnostic options using CRD. Part A of the EAACI MAUG introduces allergen molecules, families, composition of extracts, databases, and diagnostic IgE, skin, and basophil tests. Singleplex and multiplex IgE assays with components improve both sensitivity for low-abundance allergens and analytical specificity; IgE to individual allergens can yield information on clinical risks and distinguish cross-reactivity from true primary sensitization. Part B discusses the clinical and molecular aspects of IgE-mediated allergies to foods (including nuts, seeds, legumes, fruits, vegetables, cereal grains, milk, egg, meat, fish, and shellfish), inhalants (pollen, mold spores, mites, and animal dander), and Hymenoptera venom. Diagnostic algorithms and short case histories provide useful information for the clinical workup of allergic individuals targeted for CRD. Part C covers protein families containing ubiquitous, highly cross-reactive panallergens from plant (lipid transfer proteins, polcalcins, PR-10, profilins) and animal sources (lipocalins, parvalbumins, serum albumins, tropomyosins) and explains their diagnostic and clinical utility. Part D lists 100 important allergen molecules. In conclusion, IgE-mediated reactions and allergic diseases, including allergic rhinoconjunctivitis, asthma, food reactions, and insect sting reactions, are discussed from a novel molecular perspective. The EAACI MAUG documents the rapid progression of molecular allergology from basic research to its integration into clinical practice, a quantum leap in the management of allergic patients.

Improved recombinant Api m 1- and Ves v 5-based IgE testing to dissect bee and yellow jacket allergy and their correlation with the severity of the sting reaction.

BACKGROUND: No study has assessed the diagnostic sensitivity of rApi m 1 and rVes v 5 on Immulite testing system. OBJECTIVE: To compare the diagnostic sensitivity of commercially available venom recombinant allergens between the currently available immunoassays [ImmunoCAP (CAP) and Immulite (LITE)] and establish their correlation with the severity of the sting reaction. METHODS: This study evaluated 95 bee venom and 110 yellow jacket venom-allergic subjects. We measured the levels of sIgE to rApi m 1, rVes v 5 (LITE and CAP), rApi m 2 (LITE), rVes v 1 (CAP) and total IgE (CAP). Forty-nine healthy subjects served as controls. RESULTS: The diagnostic sensitivity of rApi m 1 and rVes v 5 was significantly higher with the LITE than with the CAP system (71% vs. 88% and 82% vs. 93%). The specificity of both assays for both allergens was between 94% and 98%. Twenty-nine patients that tested negative for rApi m 1 or rVes v 5 with CAP were positive with LITE, but none of the patients that tested negative with LITE were positive with CAP. The positive values of rApi m 1 and rVes v 5 were on average 2.7 and 2.3 times higher, with the LITE than with the CAP system. The combination of rApi m 1 and rApi m 2 (LITE) and the combination of rVes v 5 (LITE) and rVes v 1 (CAP) almost matched the sensitivity of native venoms (95% and 97%, respectively), whereas the diagnostic sensitivity of the combination of rVes v 5 and rVes v 1 (CAP) did not reach the sensitivity of rVes v 5 (LITE) alone (90% vs. 93%). IgE levels to venom recombinants and total IgE did not correlate with the severity of sting reaction. CONCLUSIONS & CLINICAL RELEVANCE: The use of rApi m 1 and rVes v 5 with the LITE system significantly enhanced diagnostic utility of venom recombinants and should improve the dissection of bee and yellow jacket venom allergy.

The clinical utility of basophil activation testing in diagnosis and monitoring of allergic disease.

The basophil activation test (BAT) has become a pervasive test for allergic response through the development of flow cytometry, discovery of activation markers such as CD63 and unique markers identifying basophil granulocytes. Basophil activation test measures basophil response to allergen cross-linking IgE on between 150 and 2000 basophil granulocytes in <0.1 ml fresh blood. Dichotomous activation is assessed as the fraction of reacting basophils. In addition to clinical history, skin prick test, and specific IgE determination, BAT can be a part of the diagnostic evaluation of patients with food-, insect venom-, and drug allergy and chronic urticaria. It may be helpful in determining the clinically relevant allergen. Basophil sensitivity may be used to monitor patients on allergen immunotherapy, anti-IgE treatment or in the natural resolution of allergy. Basophil activation test may use fewer resources and be more reproducible than challenge testing. As it is less stressful for the patient and avoids severe allergic reactions, BAT ought to precede challenge testing. An important next step is to standardize BAT and make it available in diagnostic laboratories. The nature of basophil activation as an ex vivo challenge makes it a multifaceted and promising tool for the allergist. In this EAACI task force position paper, we provide an overview of the practical and technical details as well as the clinical utility of BAT in diagnosis and management of allergic diseases.

Immunological and clinical factors associated with adverse systemic reactions during the build-up phase of honeybee venom immunotherapy.

BACKGROUND: Adverse systemic reactions (SRs) are more common in honeybee venom immunotherapy (VIT) than in wasp VIT. Factors that might be associated with SRs during the honeybee VIT are poorly understood. OBJECTIVE: Our aim was to evaluate risk factors for SRs during the build-up phase of honeybee venom immunotherapy. METHODS: We included 93 patients who underwent ultra-rush honeybee VIT. The adverse SRs and their severity was compared to various immunological (sIgE, tIgE, basophil CD63 response, baseline tryptase, and skin tests), patient-specific (age, sex, cardiovascular conditions and medications, and other allergic diseases), and sting-specific factors (anaphylaxis severity, time interval to onset of symptoms, and absence of cutaneous symptoms). RESULTS: Twenty-three patients (24.7%) experienced mild SRs and 13 patients (14%) severe SRs. In five patients with severe SRs, the build-up was stopped. High basophil allergen sensitivity, evaluated as dose-response curve metrics of EC15, EC50, CD-sens, AUC, or the response to submaximal 0.01 µg/mL of venom concentration, was the most significant risk factor and only independent predictor of severe SRs and/or build-up stop. Time interval of <5 min after sting to onset of symptoms and lower specific IgEs to rApi m1 was also associated with severe SRs. There was no difference in other immunological, patient-specific, or sting-specific factors, including the baseline tryptase. None of the studied factors was associated with mild SRs. CONCLUSION AND CLINICAL RELEVANCE: High basophil allergen CD63 sensitivity phenotype was a major indicator of severe adverse SRs during the build-up phase of honeybee VIT. Possibly role was also showed for short latency to filed sting reaction and low sIgE to rApi m1. Before honeybee VIT, measurement of basophil allergen sensitivity should be used to identify patients with a high risk for severe side-effects.

Sustained effect of grass pollen subcutaneous immunotherapy on suppression of allergen-specific basophil response; a real-life, nonrandomized controlled study.

BACKGROUND: An important advantage of allergen immunotherapy as compared to pharmacotherapy for allergic rhinitis is the long-term effect that persists after completing immunotherapy. The mechanism of the sustained effect of allergen immunotherapy is not completely understood. METHODS: We conducted a 7-year study of monitoring allergen-specific basophil response and serological markers in 20 subjects with moderate-to-severe grass pollen-allergic rhinitis just before beginning and after up-dosing of subcutaneous grass pollen immunotherapy, before the first pollen season, and 1-2 years after completion of 3-5 years of treatment. Comparable untreated rhinitis subjects were followed at the same time points. Clinical outcomes included assessment of symptoms, use of rescue medication, and quality of life. The basophil response was also monitored after removal of IgG antibodies. RESULTS: Basophil response assessed as area under the curve (AUC) halved during initiation of SCIT and was 55% lower 1-2 years after completing SCIT. In the untreated group, the basophil response remained comparable. Although immunotherapy-induced grass pollen-specific IgG4 levels decreased to near pre-immunotherapy levels after completing SCIT, the removal of IgG antibodies resulted in an increase in basophil response almost to the pre-immunotherapy levels. In untreated subjects, removal of IgG did not have any effect on basophil response. CONCLUSIONS: Grass pollen immunotherapy induces sustained suppression of the allergen-specific basophil response that persists after completion of treatment and could account for long-term clinical tolerance. It also seems to be associated with persistent blocking activity of IgG antibodies.

Filaggrin loss-of-function mutations are not associated with atopic dermatitis that develops in late childhood or adulthood.

BACKGROUND: The influence of filaggrin gene (FLG) mutations on early- vs. late-onset development of atopic dermatitis (AD), allergic contact dermatitis (ACD) and chronic irritant contact dermatitis (CICD) is not completely understood. OBJECTIVES: To assess the association between FLG mutations and development of AD, ACD and CICD. METHODS: This study assessed 241 patients with AD. AD developed during infancy in 85 patients, during childhood in 79 patients (32 early and 47 late) and during adulthood in 77 patients. We also included 100 patients with ACD and 44 with CICD, as well as 164 healthy controls. Four prevalent FLG loss-of-function mutations were genotyped (R501X, 2282del4, R2447X and S3247X). RESULTS: The 2282del4 mutation was significantly associated with a greater risk of AD in the entire group [odds ratio (OR) 4·33, 95% confidence interval (CI) 1·26-14·96]. However, the 2282del4 mutation was associated only with AD that developed during infancy or in early childhood (≤ 8 years: OR 20·91, 95% CI 2·73-159·9), not with AD development in late childhood or adulthood (> 8 or > 18 years), or ACD or CICD. Similar associations were also observed for the combined 2282del4 or R501X genotype. Carriers of FLG mutations also experienced a longer duration of AD and required hospitalization more often. CONCLUSIONS: FLG mutations are associated with only the early onset of AD, not late onset. Other factors should receive attention in patients with late-onset AD.

A polymorphism in ORMDL3 is associated not only with asthma without rhinitis but also with chronic obstructive pulmonary disease.

BACKGROUND: Asthma is a heterogeneous disease, and asthmatic patients without rhinitis more commonly have fixed airway obstruction, a feature that is also typical of chronic obstructive pulmonary disease (COPD). The Dutch hypothesis suggests that both COPD and asthma have common genetic risk factors. The purpose of this study was to assess the association between the polymorphism rs4795405 in the known asthma candidate gene ORMDL3 and asthma with and without rhinitis. We also analyzed COPD in order to investigate whether, in addition to a clinical overlap, there might also be a genetic overlap between COPD and asthma. METHODS: The population of this genetic association study comprised 493 Slovenian adults, distributed as follows: 131 patients with asthma (59 had asthma with rhinitis and 72 asthma without rhinitis), 59 patients with rhinitis only, 133 patients with COPD, and 170 controls. Genotypes for rs4795405 were determined using the TaqMan genotyping assay. RESULTS: rs4795405 was specifically associated with asthma without rhinitis. Assuming a recessive genetic model, we found the CC genotype in 26% of healthy controls, in 24% of patients with asthma with rhinitis (P = .862), and in 44% of patients with asthma without rhinitis (P = .006). Polymorphism rs4795405 was also associated with COPD, for which the CC genotype was found in 37% of cases (P = .045). CONCLUSIONS: rs4795405 was strongly associated with asthma without rhinitis, a subtype of asthma for which a higher degree of airway obstruction was found. These results show the importance of analyzing different asthma phenotypes in genetic association studies. We also observed a genetic overlap between COPD and asthma without rhinitis.

Short-term venom immunotherapy induces desensitization of FcεRI-mediated basophil response.

BACKGROUND: The precise immunological mechanisms for the early clinical protection of venom immunotherapy (VIT) have not yet been explained. Our aim was to evaluate whether high-affinity IgE receptor (FcεRI) and the related basophil function have a role in the induction of short-term VIT protection. METHODS: We included 60 adults and 48 children. Basophil threshold sensitivity (CD-sens) to anti-FcεRI stimulation, and FcεRI gene and cell-surface expression were assessed at the beginning and just before the first maintenance dose (MD) of 100 µg of ultra-rush VIT (day 5) and at the beginning, during buildup, and just before the first MD of 70 µg and of 100 µg of semi-rush VIT (weeks 1-2 and 5). RESULTS: We demonstrated a significant reduction in CD-sens to anti-FcεRI stimulation before the first MD in both ultra-rush and semi-rush VIT in all included subjects. FcεRI gene and/or cell-surface expression was decreased in 34-100% of subjects, with different dynamics between VIT protocols. CONCLUSION: We found a marked desensitization of FcεRI-activated basophils after short-term VIT. This suppression, which could be highly relevant for the development of early protective mechanisms, might be also related to the changes at the level of FcεRI expression.

High non-specific T lymphocyte response to the adjuvanted H1N1 vaccine in comparison with the H1N1/H3N2/B-Brisbane vaccine without adjuvant.

Shortly after the report of pandemic 2009 influenza A (H1N1), vaccine manufacturers, in conjunction with public agencies, started developing a H1N1 vaccine. In 2009, various approaches were implemented around the globe. The United States and Australia finally approved only non-adjuvanted H1N1 influenza vaccines, whereas Canada and the EU also approved adjuvanted vaccines. In 2010, seasonal influenza vaccine without adjuvant was again widely accepted in both hemispheres. The addition of adjuvant to the vaccine enhances the immunogenity of the vaccine in the presence of a relatively low amount of antigen. However, it might also induce undesirable non-specific immune response. For this reason, we conducted a prospective observational study to monitor T cell absolute count and H1N1-specific immunogenicity after 2009 and 2010 immunization. Fourteen healthy volunteers received the monovalent H1N1 AS03 adjuvanted influenza vaccine (3.5 µg of H1N1 and squalene-based adjuvant) in October 2009. The immunization was associated with a significant increase in T lymphocyte absolute count (P < 0.0001), reaching abnormal values in 57% of subjects. During this period, none of the subject showed any manifestation of severe viral infection or inflammation. Acute infection by CMV or EBV viruses was also excluded. In October 2010, the same subjects received a seasonal non-adjuvanted influenza vaccine (15 µg of each: H1N1, H3N2, and B-Brisbane). However, after 2010 immunization, no change in T lymphocyte absolute count was observed. H1N1-induced immunogenicity was good for both vaccines. Our results suggest a pronounced non-specific T cell response after AS03-adjuvanted 2009 H1N1 vaccination.

Basophil response and the induction of a tolerance in venom immunotherapy: a long-term sting challenge study.

BACKGROUND: There is no in vitro test to predict the induction of long-term tolerance in patients treated with venom immunotherapy (VIT). The aim of this study was to investigate whether immunotherapy-induced changes in basophil responsiveness reflect a state of protection and the induction of a tolerance. METHODS: Twenty-three patients with allergic reaction after Hymenoptera sting (11 wasp and 12 honeybee) were treated with VIT. In all patients, a CD63 basophil activation test was performed before the beginning of immunotherapy, after 1 year and after completing 4-6.5 years of immunotherapy (approximately 1 year after stopping). The tolerance was then evaluated by a sting challenge test. The basophil activation test was repeated 3-6 months after the challenge. RESULTS: Twenty-two subjects showed a negative sting challenge, and one subject, a positive sting challenge. Allergen-specific basophil response remained unchanged after 1 year of immunotherapy. However, after immunotherapy, a significant and approximately fourfold decrease was demonstrated in all tolerant subjects mainly in response to submaximal 0.1 µg/ml allergen concentration. This depression was sustained and did not change with the sting challenge test. In a nontolerant patient with a positive sting challenge, basophil response did not change. CONCLUSIONS: Our results suggest that the depression of allergen-specific basophil response seems to be associated with the induction of a tolerance after completing a course of VIT.

Rhinitis symptoms caused by grass pollen are associated with elevated basophile allergen sensitivity and a larger grass-specific immunoglobulin E fraction.

BACKGROUND: The mechanisms responsible for the difference between clinically irrelevant IgE-sensitization and allergic rhinitis are not fully understood. OBJECTIVE: We evaluated the humoral and cellular mechanisms that may be associated with the presence of allergic rhinitis symptoms. METHODS: We selected 26 subjects with positive grass pollen skin tests and IgE antibodies to Timothy (g6) and the major grass allergens rPhl p 1, 5b. Fourteen of those patients reported a history of allergic rhinitis. During winter, we performed a grass pollen CD63 basophile activation test using four log allergen concentrations, followed by a grass nasal provocation test (NPT). We obtained symptom scores in the subsequent pollination season. RESULTS: We showed that subjects with a positive NPT have significantly higher CD63 basophile grass pollen responsiveness than NPT-negative subjects, preferably at submaximal allergen concentrations, which represent cellular sensitivity. Moreover, basophile sensitivity positively correlated with the size of the grass-specific IgE fraction in relation to total IgE, and it was highly predictive of allergic rhinitis symptoms in the following pollination season. CONCLUSION AND CLINICAL RELEVANCE: Allergic rhinitis symptoms are significantly associated with allergen-specific basophile sensitivity. In vitro evaluation of basophile sensitivity should prove useful for distinguishing clinical phenotype of allergic sensitization.

Association of ORMDL3, STAT6 and TBXA2R gene polymorphisms with asthma.

Asthma is one of the most common chronic diseases in childhood. It is well known that genetic variability contributes to asthma risk. One of the most replicated asthma candidate genes is ORM1-like 3 (Saccharomyces cerevisiae) (ORMDL3), which has been associated with childhood asthma susceptibility. Another asthma candidate gene is signal transducer and activator of transcription 6 (STAT6), a regulator of IgE class switching. Gene coding thromboxane A2 receptor (TBXA2R), involved in chronic airway inflammation, has been associated with asthma in several genetic studies. We have studied the association of polymorphism rs4795405 in ORMDL3, rs324011 in STAT6 as well as rs8113232 and rs3786989 in TBXA2R with asthma risk, various asthma phenotypes and asthma-related symptoms. The study group consisted of 154 children with asthma, in whom clinical parameters were measured and whose asthma control and atopic status were determined. A control group comprised 71 healthy children. Genotyping was performed using an allelic discrimination assay. The ORMDL3 polymorphism rs4795405 was suggestively associated with asthma risk. Furthermore, it was significantly associated with nonatopic asthma and asthma without rhinitis. No association was detected between the STAT6 polymorphism rs324011 or the TBXA2R polymorphisms rs8113232 and rs3786989 and asthma susceptibility. However, an association between rs324011 in STAT6 with recurrent wheezing in early childhood and a suggestive association between rs8113232 in TBXA2R with rhinitis in children with asthma were observed. Our results confirmed ORMDL3 as a candidate gene for childhood asthma susceptibility. STAT6 and TBXA2R polymorphisms were not associated with asthma risk, but they were associated with asthma-related symptoms.