Eller, E., T.K. Hansen, C. Bindslev-Jensen, 2012. Clinical thresholds to egg, hazelnut, milk and peanut: results from a single-center study using standardized challenges. Ann Allergy Asthma Immunol 108:332–336.
Background: Large studies of individual thresholds and risk profiles for foods are sparse. Previous reports indicate that thresholds adjusted for the protein content in foods would be comparable. Objective: To establish and compare clinical threshold values for egg, hazelnut, milk and peanut, and correlating them to severity of symptoms. Methods: Seven hundred eighty-one challenges were performed in 487 patients (age range, 0.5–73.5 years). Using interval censoring survival analysis, the dose distribution of thresholds was fitted to a log-normal function. Symptom score was correlated to thresholds. Results: Based on the 405 challenges resulting in objective signs, similar distribution of thresholds for hazelnut, milk, and peanut challenges were found, whereas individuals with egg allergy were bimodally distributed with a high or a low threshold. Eliciting dose in 10% (95% confidence interval) was 42.9 (24-76.8) mg whole eggs, 133.8 (95.9–186.6) mg whole hazelnut, 106.5 (59.7–190.6) mg roasted peanut, and 2.9 (1.5–5.4) mL milk. Adults showed more severe symptoms and signs than children, and peanut caused more severe reactions than the 3 other foods. Conclusion: Thresholds for the different foods were not comparable, and eliciting dose for the 4 foods differed, even if adjusted for protein content. Increasing age but not a low threshold dose is associated with severe symptoms on challenge. Peanuts elicit more severe reactions than the other foods.
Willison, L.N., P. Tripathi, G. Sharma, S.S. Teuber, S.K. Sathe, K.H. Roux, 2011. Cloning, expression and patient IgE reactivity of Recombinant Pru du 6, an 11S Globulin from almond. Int Arch Allergy Immunol. 323887 DOI: 10.1159/000323887
Background: IgE-reactive proteins have been identified in almond; however, few have been cloned and tested for specific patient IgE reactivity. Here, we clone and express prunin 1 and prunin 2, isoforms of the major almond protein prunin, an 11S globulin, and assay each for IgE reactivity. Methods: Prunin isoforms were PCR-amplified from an almond cDNA library, sequenced, cloned and expressed in Escherichia coli. Reactivity to the recombinant (r) allergens, Pru du 6.01 and Pru du 6.02, was screened by dot blot and immunoblot assays using sera from almond-allergic patients and murine monoclonal antibodies (mAbs). Sequential IgE-binding epitopes were identified by solid-phase overlapping peptide analysis. Epitope stability was assessed by assaying denatured recombinant proteins by immunoblot. Results: IgE reactivity to rPru du 6.01 and rPru du 6.02 was found in 9 of 18 (50%) and 5 of 18 patients (28%), respectively. Four patients (22%) demonstrated reactivity to both isoforms. Murine anti-almond IgG mAbs also showed greater reactivity to rPru du 6.01 than to rPru du 6.02. Both stable and labile epitopes were detected. Six IgE-binding sequential epitope-bearing peptide segments on Pru du 6.01 and 8 on Pru du 6.02 were detected using pooled almond-allergic sera. Conclusions: rPru du 6.01 is more widely recognized than rPru du 6.02 in our patient population. The identification of multiple sequential epitopes and the observation that treatment with denaturing agents had little effect on IgE-binding intensity in some patients suggests an important role for sequential epitopes on prunins.
Tiwari, R.S., M. Venkatachalam, G.M. Sharma, M. Su, K.H. Roux, S.K. Sathe, 2010. Effect of food matrix on amandin, almond (Prunus dulcis L.) major protein, immunorecognition and recovery. LWT – Food Science And Technology. 43:675-83.
Amandin, the primary storage protein in almonds, contains key polypeptides recognized by almondallergic patients. A variety of food matrices representing diverse categories of foods were analyzed to assess the effect of food matrix on amandin recognition and recovery using rabbit polyclonal antibody based immunoassays. Food matrices from dairy, nuts, and vegetables typically resulted in over-estimation of amandin. Some foods representing legumes and cereals resulted in over-estimation while others in under-estimation of amandin. The amandin recovery range was 116–198 µg/100µg (dairy) 110–292 µg/100µg (tree nuts), 43–304 µg/100µg (legumes), 106–183 µg/100µg (most cereals- with the exception of barley, whole-wheat flour, wild rice and raisin bran whole mix). Amandin recovery from spices was typically low (2–85 µg/100µg) with a few exceptions where higher recoveries were observed (121–334 µg/100µg). Salt (black and white), tea, confectionery (sugar, cocoa, dark chocolate), and fruits (1–83µg/100µg) generally resulted in lower recoveries. Tested food matrices did not adversely affect amandin immunorecognition in Western blots. The pH and the extraction buffer type affected amandin recovery. The results suggest that food matrix effects as well as extraction conditions need to be carefully evaluated when developing immunoassays for amandin detection and quantification.
Schneider Chafen, J.J., S.J. Newberry, M.A. Riedl, D.M. Bravata, M. Maglione, M.J. Suttorp, V. Sundaram, N.M. Paige, A. Towfigh, B.J. Hulley, P.G. Shekelle, 2010. Diagnosing and managing common food allergies: A systematic review. JAMA. 303(18):1848-1856.
Context: There is heightened interest in food allergies but no clear consensus exists regarding the prevalence or most effective diagnostic and management approaches to food allergies. Objective: To perform a systematic review of the available evidence on the prevalence, diagnosis, management, and prevention of food allergies. Data Sources Electronic searches of PubMed, Cochrane Database of Systematic Reviews, Cochrane Database of Abstracts of Reviews of Effects, and Cochrane Central Register of Controlled Trials. Searches were limited to English-language articles indexed between January 1988 and September 2009. Study Selection: Diagnostic tests were included if they had a prospective, defined study population, used food challenge as a criterion standard, and reported sufficient data to calculate sensitivity and specificity. Systematic reviews and randomized controlled trials (RCTs) for management and prevention outcomes were also used. For foods where anaphylaxis is common, cohort studies with a sample size of more than 100 participants were included. Data Extraction: Two investigators independently reviewed all titles and abstracts to identify potentially relevant articles and resolved discrepancies by repeated review and discussion. Quality of systematic reviews and meta-analyses was assessed using the AMSTAR criteria, the quality of diagnostic studies using the QUADAS criteria most relevant to food allergy, and the quality of RCTs using the Jadad criteria. Data Synthesis: A total of 12 378 citations were identified and 72 citations were included. Food allergy affects more than 1% to 2% but less than 10% of the population. It is unclear if the prevalence of food allergies is increasing. Summary receiver operating characteristic curves comparing skin prick tests (area under the curve [AUC], 0.87; 95% confidence interval [CI], 0.81-0.93) and serum food-specific IgE (AUC, 0.84; 95% CI, 0.78-0.91) to food challenge showed no statistical superiority for either test. Elimination diets are the mainstay of therapy but have been rarely studied. Immunotherapy is promising but data are insufficient to recommend use. In high-risk infants, hydrolyzed formulas may prevent cow’s milk allergy but standardized definitions of high risk and hydrolyzed formula do not exist. Conclusion: The evidence for the prevalence and management of food allergy is greatly limited by a lack of uniformity for criteria for making a diagnosis.
