Two patients with allergy to celery - Possible role of carbohydrate determinants and difference between seeds and tuber allergenicity.

Vegetables provide important nutrients but can also induce allergic symptoms. Celery tuber allergy frequently occurs in Central European countries and can cause allergic reactions including fatal anaphylactic shocks. There is little information about allergen content in seeds. Therefore, we analyzed 2 patients with allergic reaction after remoulade sauce consumption who entered the clinic for a diagnostic work-up. The routine diagnostic included serum derived specific IgE testing by ImmunoCAP, ImmunoCAP ISAC, and skin prick tests (SPTs). Furthermore, protein extracts were prepared from both celery tuber and celery seeds and IgE binding capacity of these extracts was assessed by immunoblots, ELISA, and rat basophil leukemia (RBL) assay. We also determined role of cross-reactive carbohydrate determinants (CCDs) by IgE inhibition ELISA. Results revealed distinct protein patterns from celery tuber and seed extracts, suggesting differences in content and quantity of allergenic proteins. IgE antibodies from both sera bound to high molecular weight (HMW) proteins on immunoblots and caused high basophil response, which was also observed upon addition of glycosylated proteins as horseradish peroxidase and Api g 5, respectively. Our results indicate that it is worth considering CCDs from plant foods as a possible allergenic factor and their contribution to the mugwort-celery syndrome.

Predictive factors of amoxicillin immediate hypersensitivity and validation of PEN-FAST clinical decision rule.

BACKGROUND: The challenge of delabeling amoxicillin allergy is an important issue for patients and clinicians, especially when anaphylaxis is reported. A recent study has proposed a clinical decision rule, PEN-FAST, to identify low-risk penicillin allergies. OBJECTIVE: To validate the PEN-FAST clinical decision rule in a population with high risk of suspected immediate amoxicillin allergy and to identify clinical predictive factors of amoxicillin immediate hypersensitivity. METHODS: We retrospectively analyzed medical records of patients with a suspected immediate amoxicillin allergy who carried out an allergologic evaluation by a specialist in the Allergy Unit of Strasbourg University Hospital from 2015 to 2020. RESULTS: A total of 142 adult patients (88 women [62.0%]; median age, 52 [interquartile range, 40.3-62.0] years) were analyzed. Most of them reported anaphylaxis (68.8%). Internal validation of PEN-FAST score revealed a good discrimination with area under the curve of 0.86 (95% confidence interval, 0.79-0.92). A cutoff of less than 3 points for PEN-FAST was used to classify 29 from 142 patients at low risk of allergy, of whom only 2 (6.9%) received positive results of allergy testing. The negative predictive value for successful delabeling was 0.93 (95% confidence interval, 0.77-0.99). Predictive clinical features for immediate amoxicillin hypersensitivity were time since reaction (P < .001), time elapsed between drug intake and first symptom (P < .001), severity grade reaction (P < .001), and treatment or hospitalization required (P < .001). CONCLUSION: PEN-FAST has been validated to identify low-risk penicillin allergies in our European cohort of patients mainly reporting anaphylaxis. This is the first reported external validation of a penicillin allergy clinical decision rule internationally.

SARS-CoV-2 Pneumonia in Hospitalized Asthmatic Patients Did Not Induce Severe Exacerbation.

BACKGROUND: Viral infections are known to exacerbate asthma in adults. Previous studies have found few patients with asthma among severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia cases. However, the relationship between SARS-CoV-2 infection and severe asthma exacerbation is not known. OBJECTIVE: To assess the frequency of asthma exacerbation in patients with asthma hospitalized for SARS-CoV-2 pneumonia and compare symptoms and laboratory and radiological findings in patients with and without asthma with SARS-CoV-2 pneumonia. METHODS: We included 106 patients between March 4 and April 6, 2020, who were hospitalized in the Chest Diseases Department of Strasbourg University Hospital; 23 had asthma. To assess the patients' asthma status, 3 periods were defined: the last month before the onset of COVID-19 symptoms (p1), prehospitalization (p2), and during hospitalization (p3). Severe asthma exacerbations were defined according to Global INitiative for Asthma guidelines during p1 and p2. During p3, we defined severe asthma deterioration as the onset of breathlessness and wheezing requiring systemic corticosteroids and inhaled ß2 agonist. RESULTS: We found no significant difference between patients with and without asthma in terms of severity (length of stay, maximal oxygen flow needed, noninvasive ventilation requirement, and intensive care unit transfer); 52.2% of the patients with asthma had Global INitiative for Asthma step 1 asthma. One patient had a severe exacerbation during p1, 2 patients during p2, and 5 patients were treated with systemic corticosteroids and inhaled ß2 agonist during p3. CONCLUSIONS: Our results demonstrate that patients with asthma appeared not to be at risk for severe SARS-CoV-2 pneumonia. Moreover, SARS-CoV-2 pneumonia did not induce severe asthma exacerbation.

Do Plantago lanceolata Skin Prick Test-Positive Patients Display IgE to Genuine Plantain Pollen Allergens? Investigation of Pollen Allergic Patients from the North-East of France.

BACKGROUND: English plantain (Plantago lanceolata) is an important weed pollen allergen source triggering allergic symptoms during summer. To elucidate genuine versus cross-reactive sensitization, we investigated IgE reactivity patterns and inhibition capacities of plantain-sensitized patients. METHODS: Sera of 35 rhinoconjunctivitis patients from the north-east of France with positive skin prick tests (SPT) to Plantago lanceolata pollen were tested with clinically relevant allergen sources using ELISA, ImmunoCAP, and immunoblot inhibition. RESULTS: The patients were multisensitized with additional reactivity to grass (94.3%), ash (74.3%), birch (71.4%), and mugwort (55.2%) pollen in SPT. Sensitization prevalence to allergen molecules was 34.3% (Pla l 1), 94.3% (Phl p 1/5), 60.0% (Ole e 1), 65.7% (Bet v 1), 37.1% (profilin), and 40.0% (CCD). In immunoblot, IgE reactivity to plantain pollen was inhibited with relevant pollen extracts and purified rPla l 1. Two sera did not reveal any IgE cross-reactivity, while reactivity to plantain was efficiently inhibited by grass pollen in the sera of 10 patients. The sera from 17 different patients could be inhibited by grass, birch, or ash pollen to varying degrees. Thus, only 37.1% of our patients demonstrated true plantain pollen sensitization, while 62.9% were solely positive due to IgE cross-reactive molecules from other clinically relevant pollen. CONCLUSIONS: Plantain pollen-sensitized patients are multi-reactors demonstrating varying and complex IgE-reactivity profiles. In vivo and in vitro tests using extracts are typically blurred due to the presence of homologous allergens or CCD in grass, birch, or ash pollen. So far, Pla l 1 represents the only indicative marker allergen for the diagnosis of genuine plantain pollen sensitization.

[Contribution of molecular biology to allergology practice]. / Apport de la biologie moléculaire a la pratique de l'allergologie.

In the last 20 years, numerous allergen proteins have been purified and cloned. Analyses of individual sera from patients sensitized to allergenic sources revealed great variety in the responses to molecular allergens. We have tried to show how molecular allergology had modified the patients'treatments by bringing new interpretation to cutaneous tests and serological IgE determination. The consequences for the future concerning diagnosis and immunotherapy protocols are underlined.

Skin test diagnosis of grass pollen allergy with a recombinant hybrid molecule.

BACKGROUND: A recombinant hybrid molecule (HM) consisting of 4 major allergens from timothy grass (Phl p 1, 2, 5, and 6) was expressed in Escherichia coli, purified, and characterized regarding its immunologic properties. OBJECTIVE: We sought to determine whether the recombinant HM can be used for the diagnosis of grass pollen allergy by means of skin testing. METHODS: Skin prick testing was performed in 32 patients with grass pollen allergy and in 9 control individuals by using increasing concentrations (4, 12, 36, and 108 mug/mL) of the HM and using commercial grass pollen extract. Specific IgE reactivities against the HM, grass pollen extract, and a panel of purified grass pollen allergens (recombinant Phl p 1, 2, 5, 6, 7, 12, and 13 and natural Phl p 4) were measured by means of ELISA, and timothy grass pollen-specific IgE levels were determined by using ImmunoCAP. RESULTS: Grass pollen allergy was diagnosed in all patients by means of skin testing with the HM. No false-positive skin test responses were obtained in the control individuals. There was an excellent correlation between IgE levels obtained with the HM and natural grass pollen extract measured by means of ELISA (r = 0.98, P < .0001) and by means of ImmunoCAP (r = 0.98, P < .0001). CONCLUSIONS: The recombinant HM permitted accurate and specific in vivo diagnosis of grass pollen allergy in all tested patients. It can be considered a well-defined tool for the diagnosis and perhaps for immunotherapy of grass pollen allergy. CLINICAL IMPLICATIONS: A recombinant HM can replace traditional allergen extracts for skin test-based diagnosis of grass pollen allergy.