Search

Anaphylaxis is the most acute and life-threatening manifestation of allergic disorders. Currently, there is a need to improve its medical management and increase the understanding of its molecular mechanisms. This study aimed to quantify the extravasation underlying human anaphylactic reactions and propose new theragnostic approaches.Molecular determinations were performed in paired serum samples obtained during the acute phase and at baseline from patients presenting with hypersensitivity reactions. These were classified according to their severity as Grades 1, 2 and 3, the two latter being considered anaphylaxis. Tryptase levels were measured by ImmunoCAP, and serum protein concentration was quantified by Bradford assay. Human serum albumin (HSA) and haemoglobin beta subunit (HBB) levels were determined by Western blot and polyacrylamide gel electrophoresis, respectively.A total of 150 patients were included in the study. Of them, 112 had experienced anaphylaxis (83 and 29 with Grade 2 and 3 reactions, respectively). Tryptase diagnostic efficiency substantially improved when considering patients' baseline values (33%-54%) instead of the acute value threshold (21%). Serum protein concentration and HSA significantly decreased in anaphylaxis (p .0001). HSA levels dropped with the severity of the reaction (6% and 15% for Grade 2 and 3 reactions, respectively). Furthermore, HBB levels increased during the acute phase of all hypersensitivity reactions (p .0001).For the first time, the extravasation underlying human anaphylaxis has been evaluated based on the severity of the reaction using HSA and protein concentration measurements. Additionally, our findings propose new diagnostic and potential therapeutic approaches for this pathological event.

Background: Anaphylaxis is the most severe manifestation of allergic disorders. Diagnostic and understanding of molecular mechanisms need to improve. Extracellular vesicles (EVs) play a key role in cellular communication offering new possibilities to unravel patient-based particularities. The aim of this study is to analyze the protein profile of anaphylaxis-derived EVs providing a resource of potential markers for anaphylactic reactions, and to characterize their molecular mechanisms. Methods: EVs were isolated from 86 plasma samples (collected from 43 patients) during the acute phase of anaphylaxis (AnEVs) and at their baseline (BEVs). For comparison, EVs were characterized and their protein patterns were analyzed by mass spectrometry-based quantitative proteomics (LC-MS/MS). System Biology Analysis (SBA) was applied to identify main canonical pathways and molecules involved. In addition, in vitro permeability assays based on EVs-endothelial cells (ECs) were performed. Results: Differential proteomic analysis performed in 10 EVs paired patients’ samples identified 1206 proteins of which 99 were modulated in the AnEVs signature. CDC42, Ficolin-2 and S100A9 enrichment was confirmed in a larger cohort of patients. SBA revealed diverse group of immune proteins as the main canonical pathways altered in AnEVs. Thus, leukocyte extravasation and granulocyte adhesion-diapedesis processes stand out. In addition, marked-EVs from anaphylactic patients were captured by ECs decreasing the resistance of human endothelial monolayers. Conclusion: Our findings identify for the first time a differential EVs pattern signature in anaphylaxis revealing a source of potential biomarkers. Furthermore, these vesicles could participate in altered immune molecular mechanisms and present a role increasing vascular permeability.

Background Sin a 2 (11S globulin) and Ara h 1 (7S globulin) are major allergens from yellow mustard seeds and peanut, respectively. The ability of these two allergens to interact with lipid components remains unknown. Objective To study the capacity of Sin a 2 and Ara h 1 to interact with lipid components and the potential effects of such interaction in their allergenic capacity. Methods Spectroscopic and SDS-PAGE binding assays of Sin a 2 and Ara h 1 with different phospholipid vesicles and gastrointestinal and endolysosomal digestions in the presence or absence of lipids were performed. The capacity of human monocyte-derived dendritic cells (hmoDCs) to capture food allergens in the presence or absence of lipids, the induced cytokine signature, and the effect of allergens and lipids to regulate TLR2-L-induced NF-kB/AP-1 activation in THP1 cells were analyzed. Results Sin a 2 and Ara h 1 bind phosphatidylglycerol (PG) acid but not phosphatidylcholine (PC) vesicles in a pH-dependent manner. The interaction of these two allergens with lipid components confers resistance to gastrointestinal digestion, reduces their uptake by hmoDCs, and enhances their stability to microsomal degradation. Mustard and peanut lipids favor a proinflammatory environment by increasing the IL-4/IL-10 ratio and IL-1β production by hmoDCs. The presence of mustard lipids and PG vesicles inhibits TLR2-L-induced NF-kB/AP-1 activation in THP1 cells. Conclusion Sin a 2 and Ara h 1 interact with lipid components, which might well contribute to explain the potent allergenic capacity of these two clinically relevant allergens belonging to the cupin superfamily.

Background: Little information is available on the clinical efficacy of sublingual immunotherapy (SLIT) using extracts derived from mammalian epithelia. Objectives: To assess clinical efficacy of cat SLIT based on natural exposure challenge test (NCT). Material and methods: Fifty cat allergic patients with rhinoconjunctivitis with or without asthma were included in a randomized double blind placebo controlled clinical trial of cat SLIT during 1 year. Twenty-five patients received active treatment and 25 placebo. Sublingual immunotherapy efficacy was assessed by natural exposure challenge to a cat in a cat-room and by skin tests. Airborne Fel d 1 levels, symptom scores and peak expiratory flow (PEF) values were monitored. Results: Thirty-three (66%) out of 50 patients completed the treatment. Fel d 1 content of the maximum concentration was 0.51 μg per ml. During the build up phase, the accumulated dose was 1.7 μg of Fel d 1 and during the entire length of the study was 17.1. No adverse reports were reported. The active group showed a marked reduction (62%) in symptoms during the NCT (P

Background: Bakery workers may develop IgE-mediated allergy to liquid and aerosolized hen's egg proteins that are commonly used in the baking and confectionery industries. Methods: We studied four bakery workers who had work-related allergic respiratory symptoms upon exposure to egg aerosols. The causative role of egg proteins in their respiratory symptoms was investigated by immunologic and specific inhalation challenge (SIC) tests. Results: Skin prick tests to egg white extract and to lysozyme gave positives responses in all the subjects, to ovalbumin in two, to ovomucoid in one and to egg yolk in two subjects. They were also sensitized to wheat, rye and barley flours. Specific IgE determinations to egg white were positive in all patients, to lysozyme in two, to ovalbumin in three, to ovomucoid in two and to egg yolk in two of them. Methacholine inhalation tests revealed bronchial hyperresponsiveness in all workers (PC20

Background: Lipid transfer proteins are molecules widely distributed in fruits. Sensitization to LTP is frequent in fruit sensitive patients. The aims of this study were to purify LTP and to assess the content of LTP in ripe peach peel and pulp extracts by ELISA inhibition using polyclonal antibodies. Methods: LTP was purified from ripe yellow peach peel by two different column chromatography methods. A polyclonal antibody was produced by injecting purified LTP into two New Zealand white rabbits. ELISA inhibition and rabbit monospecific polyclonal antibody were used to calculate the LTP content in Springcrest and Miraflores varieties of peach peel and pulp extracts. Purified LTP (2.5 mg/ml) was used to skin test 24 peach-sensitive patients. Results: The purified LTP showed a single band at approximately 9 kDa. The polyclonal antibody raised anti LTP recognized only the LTP molecule in the peach extracts. LTP content, expressed in µg/mg of freeze-dried extract in four extracts were: yellow peach peel, 15.48; yellow peach pulp 2.25; red peach peel 14.67 and red peach pulp 1.84. Twenty patients (83.3%) had a positive skin test with purified LTP. Conclusions: We have developed a system to determine the concentration of LTP in peach extracts. LTP in peel extracts is approximately seven times greater than in pulp.

Background:Act d 12 (11S globulin) and Act d 13 (2S albumin) are two novel relevant allergens from kiwi seeds that might be useful to improve the diagnostic sensitivity and the management of kiwifruit-allergic patients. Objective:To perform a comprehensive structural and immunological characterization of purified Act d 12 and Act d 13 from kiwi seeds. Methods:Sera from 55 well-defined kiwifruit-allergic patients were used. Act d 12 and Act d 13 were purified by chromatographic procedures. Circular dichroism, mass spectrometry, concanavalin A detection, immunoblotting, enzyme-linked immunosorbent assays, basophil activation tests, and IgE-inhibition experiments were used. Results:Act d 12 and Act d 13 were purified from kiwi seeds to homogeneity by combining size-exclusion, ion-exchange, and RP-HPLC chromatographies. Both purified allergens preserve the structural integrity and display typical features of their homologous counterparts from the 11S globulin and 2S albumin protein families, respectively. These allergens are released from kiwi seeds after oral and gastric digestion of whole kiwifruit, demonstrating their bioavailability after ingestion. The allergens retain the capacity to bind serum IgE from kiwifruit-allergic patients, induce IgE cross-linking in effector-circulating basophils, and display in vitro IgE cross-reactivity with homologous counterparts from peanut and tree nuts. Conclusion:Purified Act d 12 and Act d 13 from kiwi seeds are well-defined molecules involved in in vitro IgE cross-reactivity with peanut and tree nuts. Their inclusion in component-resolved diagnosis of kiwifruit allergy might well contribute to improve the diagnostic sensitivity and the management of kiwifruit-allergic patients.

We report the clinical characteristics of peach allergy encountered in a population of peach-allergic patients. We evaluated 165 patients. The 70 peach-allergic patients were diagnosed through clinical history, the skin prick-prick test, and open oral challenge and rub tests to peach. As a pollinic control group, 95 pollen-allergic patients were also evaluated. Some 49% of the patients were male and 51% female. The mean age was 20 +/- 8 years. Oral allergy syndrome (86%) was the most common symptom, followed by contact urticaria (61%) and systemic symptoms (26%). Some 67% of the patients were allergic to peach pulp and 36% reported symptoms related to canned peach. Canned peach and pulp symptoms were statistically associated (P0.01), and symptoms to canned peach were more frequently reported by patients with systemic symptoms (P0.05). On evaluation of the peach-allergic patients' characteristics, three risk factors--allergy to peach pulp, allergy to canned peach, and peach allergy in non-pollen-allergic patients--were found, indicating development of systemic symptoms on eating peach. Most of the peach-allergic patients (81%) also had pollen allergy, which was linked to a higher prevalence of asthma (73%) than in the pollen-allergic patients of the control group (48%); this difference was statistically significant (P0.01). Finally, two groups were clearly defined by the seriousness of the peach allergy--the non-pollen-allergic patients were more predisposed to the occurrence of systemic symptoms (50%), and the pollen-allergic patients to asthma (70%).

In recent years, patients allergic to amoxicillin (AX) but with good tolerance of penicillin G (PG) have been described. It has been suggested that the epitope implicated in this type of sensitization might be located on the side-chain of the AX molecule. Thus, cross-reactivity between AX and cephadroxil (CEPH), a cephalosporin which shares an identical side-chain with AX, is suspected. This study aimed to demonstrate clinical cross-reactivity between AX and CEPH in patients allergic to AX and showing good tolerance of PG. In 76 of 576 subjects with suspected allergic reaction to PG and/or AX, the diagnosis of allergy was confirmed. All of these had specific IgE to PG, penicillin V, or AX, and/or positive skin tests to PPL (penicilloyl-polylysine), or MDM (minor determinant mixture), or PG, or AX, and/or positive challenge tests with PG and/or AX. Sixteen subjects (21%) allergic to AX (11 with positive skin test and five with positive challenge test to AX) and good tolerance of PG (all with negative parenteral challenge test) were selected. These 16 patients were subsequently challenged with CEPH (up to 500 mg). Fourteen patients tolerated CEPH, and two (12%) had an immediate allergic reaction. Our study indicates that allergy to the side-chain of aminopenicillins seems to have little clinical relevance in patients with allergic reactions to aminopenicillins but with good tolerance of PG, as 88% of patients with this clinical characteristic tolerate a cephalosporin which shares an identical side-chain. It seems that IgE from most of these patients recognizes an epitope different from the side-chain and the beta-lactam ring.

Background: Quantitative relationships between immunological reactivity, non-specific bronchial responsiveness and bronchial responsiveness to allergens have scarcely been investigated in occupational asthma. Methods: We assessed the above relationships in 24 subjects with baker's asthma. The skin endpoint titration to bakery allergens as a measure of immunological reactivity, together with the methacholine PC20 and allergen PC20 during early asthmatic reaction were determined. Results: All patients had positive skin tests to some bakery allergens (wheat and rye flour, soybean flour, fungal enzymes and egg white proteins) and bronchial hyperresponsiveness to methacholine. Specific inhalation challenge (SIC) tests were performed with aqueous allergen extracts of cereal flour (n = 14), soybean (n = 8), baking enzymes (n = 12), and egg white proteins (n = 8) in sensitized workers. A positive asthmatic reaction was observed in 84% of the inhalation challenges. SIC elicited isolated early asthmatic reactions in 62%, dual reactions in 32% and isolated late reactions in 5%. Multiple linear regression analysis showed allergen PC20 as a function of skin sensitivity to allergen and methacholine PC20, yielding the following highly significant regression formula: log-allergen PC20 = 0.18 + 0.99 log(skin sensitivity) + 0.343 log(methacholine PC20) (r = 0.89, P

Background: We report on a 21-year-old atopic woman who developed urticaria, angioedema of the face, and wheezy dyspnea shortly after drinking beer and after eating a corn-made snack. Methods: Skin prick tests and specific IgE determinations to beer ingredients and cereal extracts were performed. Immunoblotting inhibition assays were carried out to investigate possible common allergens shared by barley and malt with corn. Results: Skin prick tests and specific IgE measurements with beer, barley, malt, wheat, corn, rye, rice, and oat flour were positive. Ten pollen-allergic patients showed negative skin tests to beer. Double-blind, placebo-controlled, oral challenge tests with sodium metabisulfite and wheat flour were negative. Immunoblotting demonstrated several IgE-binding bands at 31–56 kDa in malt and barley extracts, and a major band at 38 kDa in the beer extract. Immunoblot inhibition assays showed that malt extract was able to inhibit most of the IgE-binding bands in wheat and corn extracts, whereas corn did not produce significant inhibition to barley and malt extracts. Conclusions: This patient developed type I hypersensitivity to barley/malt and corn. Although she also showed IgE reactivity to wheat and other cereals, no symptoms were elicited upon ingestion of these cereals, probably indicating latent sensitization to them.

Thymostimulin is a partially purified extract of calf thymus, consisting of a group of polypeptides with a total molecular weight of approximately 12,000 D. It is used as an immunologic response modifier in primary and secondary immunodeficiencies. We report a patient who had a severe anaphylactic reaction with the first injection of thymostimulin. Type I hypersensitivity to thymostimulin was suggested by an immediate skin test response, specific IgE determination by indirect ELISA and a positive histamine release test. This patient also reacted to bovine serum albumin (BSA), fetal calf serum (FCS) and cow hair and dander. The controls did not react to any of these tests. Clinicians need to be aware that the use of medical products of xenogeneic origin may lead to severe allergic reactions.

Asthma induced by cereal flour is a long recognized entity. We present studies of three patients affected by asthma related to exposure to cereal flour contained in animal formula feeds. Skin prick test performed with the formula feed components showed positive reactions to cereal flours (wheat, rye and barley) and negative to the other substances in these formulas. Specific anti-wheat, rye and barley flour IgE antibodies were found by RAST. Bronchial provocation tests (BPT) with wheat flour (patients 1 and 2) and barley flour (patient 3) all showed immediate responses. These findings suggest that our patients' symptoms were caused by an IgE-mediated hypersensitivity to cereal flours from animal formula feeds. We call attention to the importance of cereal flours in animal formula feeds as a cause of occupational asthma in farm and animal feeders.

Allergy to white potato has rarely been described. We report two cases of atopic patients, housewives, in whom peeling raw potatoes precipitated rhinoconjunctivitis and asthmatic attacks, and, in one of them, contact urticaria. Type I hypersensitivity to raw potato antigens was demonstrated by means of immediate skin test reactivity, specific IgE determination by RAST, basophil degranulation, histamine release test and an immediate bronchial provocation test response to raw potato extract. The controls did not react to any of these tests. Potato allergenic constituent is currently being investigated but, as far as we know, it is heat-labile and has an MW of more than 10 Kd.