The role of basophils in anaphylaxis is unclear. We sought to investigate whether basophils have an important role in human anaphylaxis. In an emergency department study we recruited 31 patients with acute anaphylaxis, predominantly to Hymenoptera venom. We measured expression of basophil activation markers (CD63 and CD203c); the absolute number of circulating basophils; whole-blood FCER1A, carboxypeptidase A3 (CPA3), and L-histidine decarboxylase (HDC) gene expression; and serum markers (CCL2, CCL5, CCL11, IL-3, and thymic stromal lymphopoietin) at 3 time points (ie, during the anaphylactic episode and in convalescent samples 7 and 30 days later). We recruited 134 patients with Hymenoptera allergy and 76 healthy control subjects for comparison. We then investigated whether the changes observed during venom-related anaphylaxis also occur during allergic reactions to food in 22 patients with peanut allergy undergoing double-blind, placebo-controlled food challenge to peanut. The number of circulating basophils was significantly lower during anaphylaxis (median, 3.5 cells/[micro]L) than 7 and 30 days later (17.5 and 24.7 cells/[micro]L, P ( .0001) and compared with those in patients with venom allergy and healthy control subjects (21 and 23.4 cells/[micro]L, P ( .0001). FCER1A expression during anaphylaxis was also significantly lower than in convalescent samples (P (- .002) and control subjects with venom allergy (P ( .0001). CCL2 levels (but not those of other serum markers) were significantly higher during anaphylaxis (median, 658 pg/mL) than in convalescent samples (314 and 311 pg/mL at 7 and 30 days, P ( .001). Peanut-induced allergic reactions resulted in a significant decrease in circulating basophil counts compared with those in prechallenge samples (P = .016), a decrease in FCER1A expression (P = .007), and an increase in CCL2 levels (P = .003). Our findings imply an important and specific role for basophils in the pathophysiology of human anaphylaxis.
COBISS.SI-ID: 33355481
The head of the research program, Prof. Mitja Košnik, MD, PhD, was a member of a group that developed guidelines for the treatment of patiens with a Hymenoptera venom hypersensitivity. Systemic reactions to hymenoptera venom are the leading cause for anapylaxis in most European countries, and are potentially life-threatening. Systemic allergic sting reactions have been reported in up to 7.5% of adults and in up to 3.4% of children. They can be mild and restricted to the skin or moderate-to-severe with a risk of life-threatening anaphylaxis. The only treatment to prevent further systemic sting reactions is venom immunotherapy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Venom Immunotherapy as part of the EAACI Guidelines on Allergen Immunotherapy initiative. The guideline aims to provide evidence-based recommendations for the use of venom immunotherapy, has been informed by a formal systematic review and meta-analysis and produced using the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included representation from a range of stakeholders. Venom immunotherapy is indicated in venom allergic children and adults to prevent further moderate to severe systemic sting reactions. Venom immunotherapy is also recommended in adults with only generalized skin reactions as it results in significant improvements in quality of life compared to carrying an adrenaline auto-injector. This guideline aims to give practical advice on performing venom immunotherapy. Key sections cover general considerations before initiating venom immunotherapy, evidence-based clinical recommendations, risk factors for adverse events and for relapse of systemic sting reaction, and a summary of gaps in the evidence.
COBISS.SI-ID: 33365465
New recombinant allergens have an improved diagnostic specificity and sensitivity. This study has assessed the diagnostic sensitivity of the new recombinant allergens rApi m1 and rVes v5 in a large group of patients.. The goal was 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.This study evaluated 95 bee venom and 110 yellow-jacket venom allergic subjects. We measured the levels of sIgE to rApi m1, rVes v5 (LITE and CAP), rApi m2 (LITE), rVes v1 (CAP) and tIgE (CAP). Forty-nine healthy subjects served as controls. The diagnostic sensitivity of rApi m1 and rVes v5 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 m1 or rVes v5 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 m1 and rVes v5 were on average 2.7 and 2.3 times higher, with the LITE than with the CAP system. The combination of rApi m1 and rApi m2 (LITE) and the combination of rVes v5 (LITE) and rVes v1 (CAP) almost matched the sensitivity of native venoms (95% and 97%, respectively), whereas the diagnostic sensitivity of the combination of rVes v5 and rVes v1 (CAP) did not reach the sensitivity of rVes v5 (LITE) alone (90% vs. 93%). IgE levels to venom recombinants and total IgE did not correlate with the severity of sting reaction. The use of rApi m1 and rVes v5 with the LITE system significantly enhanced diagnostic utility of venom recombinants and should improve the dissection of bee and yellow-jacket venom allergy.
COBISS.SI-ID: 38055685
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. This study dealt with basophil response during specific immunotherapy.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 the completion of 3–5 years of treatment. Comparable untreated rhinitis subjects were followed at the same time points. Clinical outcomes included the assessment of symptoms and of the quality of life, as well as use of rescue medication. Basophil response was monitored after the removal of IgG antibodies. 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. 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.
COBISS.SI-ID: 37928453
Adverse systemic reactions (SRs) are more common in honeybee venom immunotherapy (VIT) than in wasp VIT. Factors that might be associated with SRs during honeybee VIT are poorly understood. Our aim was to evaluate risk factors for SRs during the build-up phase of honeybee venom immunotherapy. 93 patients who underwent ultra-rush honeybee VIT were included. The adverse SRs and their severity were 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). 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 % g/mL of venom concentration, was the most significant risk factor and the 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. 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 shown 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.
COBISS.SI-ID: 37963013
Hereditary angioedema (HAE) is a rare autosomal dominant disease characterized by swelling of the face, lips, tongue, larynx, genitalia, or extremities, with abdominal pain caused by intra-abdominal edema. HAE is caused by mutations affecting the C1 inhibitor gene, SERPING1, resulting in low levels of C1 inhibitor (Type I HAE) or normal levels of ineffective C1 inhibitor (Type II HAE). A nationwide survey identified nine unrelated families with HAE in Slovenia, among whom 17 individuals from eight families were recruited for genetic analyses. A diagnosis of HAE was established in the presence of clinical and laboratory criteria (low C1 inhibitor antigenic levels and/or function), followed up by a positive family history. Genetic studies were carried out using PCR and sequencing to detect SERPING1 mutations in promoter, noncoding exon 1, the 7 coding exons, and exon-intron boundaries. Multiplex ligation-dependent probe amplification was performed in order to search for large deletions/duplications in SERPING1 gene. A mutation responsible for HAE was identified in patients from seven families with the disease. In HAE type I families, one previously reported substitution (Gln67Stop, c.265C.T) and four novel mutations were identified. The new mutations included two missense substitutions, Ser128Phe (c.449C.T), and Glu429Lys (c.1351G.A), together with two frameshift mutations, indel (c.49delGinsTT) and deletion (c.593_594delCT). Both families with HAE type II harbored the two well-known substitutions affecting the arginyl residue at the reactive center in exon 8, Arg444Cys (c.1396C.T) and Arg444His (c.1397G.A), respectively. In one patient only the homozygous variant g.566T.C (c.-21T.C) was identified. Our study identified four novel mutations in the Slovenian HAE population, highlighting the heterogeneity of mutations in the SERPING1 gene causing C1 inhibitor deficiency and HAE. In a single patient with HAE a homozygous variant g.566T.C (c.-21T.C) might be responsible for the disease. Genetic testing has been implemented as a routine diagnostic procedure for HAE.
COBISS.SI-ID: 4586815
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 (Fc?RI) and the related basophil function have a role in the induction of short-term VIT protection. We included 60 adults and 48 children. Basophil threshold sensitivity (CD-sens) to anti-Fc?RI stimulation, and Fc?RI gene and cell-surface expression were assessed at the beginning and just before the first maintenance dose (MD) of 100 mug of ultra-rush VIT (day 5) and at the beginning, during buildup, and just before the first MD of 70 mug and of 100 mug of semi-rush VIT (weeks 1–2 and 5). We demonstrated a significant reduction in CD-sens to anti-Fc?RI stimulation before the first MD in both ultra-rush and semi-rush VIT in all included subjects. Fc?RI gene and/or cell-surface expression was decreased in 34–100% of subjects, with different dynamics between VIT protocols. We found a marked desensitization of Fc?RI-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 Fc?RI expression.
COBISS.SI-ID: 30233305
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 response reflect a state of protection and the induction of tolerance. 23 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 (approx. 1 year after stopping). Tolerance was then evaluated by a sting challenge test. Basophil activation test was repeated 3-–6 months after the challenge. 22 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 mug/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. 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.
COBISS.SI-ID: 29842393
The effects of pollen immunotherapy on effector cells of allergic inflammation, such as mast cells and basophils, are poorly understood. For this reason, an open study on basophil allergen threshold sensitivity during birch pollen immunotherapy was conducted. Basophil sensitivity was measured by CD63 flow cytometry in 14 patients with moderate-severe intermittent birch pollen rhinitis using four log allergen concentrations. In nine patients, basophil sensitivity was analysed before and during treatment with subcutaneous birch immunotherapy (perennial scheme with allergoid). We also included eight birch-allergic donor subjects for IgG inhibition experiments and eight control subjects. There was a decrease in basophil allergen threshold sensitivity after 2, 3, and 5 months of immunotherapy. This decrease correlated with an improvement in patients' symptoms measured on a visual analogue scale. The serum obtained after immunotherapy induced a significant decrease in allergen threshold sensitivity in donor birch-allergic basophils. This inhibition was not observed after IgG depletion from the serum. In this study, we showed that birch immunotherapy-induced IgG antibodies are associated with a reduction in basophil allergen threshold sensitivity. Further studies are needed to show whether the changes in basophil sensitivity are of clinical relevance in pollen immunotherapy.
COBISS.SI-ID: 27154393
Airway angiogenesis may be an important part of structural remodelling in the pathogenesis of asthma. The development of asthma is frequently preceded by rhinitis. We sought to determine whether the levels of angiogenesis-related factors are elevated in airways of patients with rhinitis or controlled asthma. Induced sputum of 18 rhinitis patients, 16 asthmatic patients, and 15 healthy controls was analysed. The concentrations of angiogenin, vascular endothelial growth factor (VEGF), IL-8,fibroblast growth factor (bFGF), and TNF-alpha were measured by cytometric bead arrays. We found significantly increased angiogenin and VEGF concentrations in the induced sputum supernatant of both rhinitis and asthma patients compared with that of the healthy control group (P( or =0.0005). With the exception of TNF-alpha, there was no difference in the other angiogenic factors; TNF-alpha levels were higher in the rhinitis group than in the control group (P=0.02). These in vivo results suggest increased airway angiogenesis in patients with rhinitis without asthma as well as in corticosteroid-treated and well-controlled asthma patients.
COBISS.SI-ID: 25417689