Diane L. Squillace

Laboratory investigation of deaths due to anaphylaxis

To establish a useful laboratory protocol to investigate possible cases of fatal anaphylaxis, we measured mast-cell-derived tryptase levels and allergen-specific immunoglobulin E (IgE) antibody levels in sera obtained prior to or within 24 h after death from 19 anaphylaxis victims. Elevated serum tryptase levels (range = 12 ng/mL to 150 micrograms/mL) were found in nine of nine Hymenoptera sting fatalities, six of eight food-induced fatalities, and two of two reactions to diagnostic therapeutic agents. Tryptase levels were normal (less than 10 ng/mL) in 57 sequential sera obtained postmortem from six control patients. Tryptase could not be measured in pleural or pericardial fluids for technical reasons. Serum IgE antibodies were elevated in five of the nine Hymenoptera sting fatalities and in eight of the eight fatal food reactions; assays were unavailable for the two diagnostic/therapeutic agents. If elevated, the victims serum IgE antibodies to food could be used to identify allergens in uneaten portions of foods consumed shortly before the anaphylactic event. IgE antibodies were moderately stable during storage in a variety of anticoagulants at room temperature for up to 11 weeks. Elevated mast-cell-derived tryptase levels in postmortem sera reflect antemortem mast cell activation and may be used as a marker for fatal anaphylaxis. If assays are available for IgE antibodies to relevant allergens, such assays provide evidence for antemortem sensitization; these assays may be modified to identify allergens in foods consumed by victims of food-induced anaphylaxis.

Fatal anaphylactic reactions induced by peanuts.

Peanuts are a common cause of food allergy, but they have infrequently been documented as causing fatal anaphylactic reactions. We review five previously reported fatalities caused by peanut allergy, along with data on IgE binding proteins in extracts of a commercial product containing peanuts that have been deflavored and reflavored and colored to resemble walnuts, pecans, or almonds. Ingestion of this product may pose hazards to peanut-sensitive persons. Finally, we identify several factors that may contribute to the severity and possible lethality of food-induced anaphylaxis.

Ovalbumin content of influenza vaccines

Some 2009–2010 influenza vaccine package inserts indicate that each dose may contain up to 1 μg ovalbumin; others do not provide information on ovalbumin content. The ovalbumin content of influenza vaccines is important if these vaccines are administered to patients with egg allergy. In a previous publication (1) we (MAR and JTL) proposed a protocol for administration of influenza vaccine to patients with egg allergy when the ovalbumin content of the vaccine is unknown.

Shared Allergenic Activity in Asian (Blattella asahinai), German (Blattella germanica), American (Periplaneta americana), and Oriental (Blatta orientalis) Cockroach Species

Whole-body extracts of the feral and peridomestic Asian cockroach (Blattella asahinai) and the three domestic cockroach species, German (Blattella germanica), American (Periplaneta americana), and Oriental (Blatta orientalis), were compared allergenically using an IgE serum pool from 4 German cockroach sensitive individuals. In crossover radioallergosorbent inhibition analysis, the Asian cockroach shared allergenic activity primarily with the German cockroach polymer and to a lesser extent with either the American or Oriental cockroach polymers. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and thin-layer isoelectric focusing analysis of the extracts showed similar although varying intensities of Coomassie blue stained banding patterns among five extracts analyzed. Electroblotting analysis with 12.5% SDS-PAGE of the whole-body German cockroach extract and IgE serum from individuals sensitive to German cockroach revealed eight allergenic components with apparent molecular weights of 92, 80, 67, 48, 36, 27, 25 and 18 kD. Five components could be identified in the whole-body extract of the Asian cockroach corresponding to apparent molecular weights of 92, 67, 48, 40, and 32 kD. Analysis of individual serum by immunoblot analysis with each of the cockroach extracts showed considerable heterogenicity in the IgE-binding pattern. Although the Asian cockroach demonstrated considerable cross-reacting allergenic components to German and relatively fewer cross-reacting allergenic components to either the Oriental or American, it is too early to establish genus- or species-specific cockroach allergens. It is important to point out that German cockroach sensitive individuals should be made aware of the potential exposure of Asian cockroach aeroallergens both indoors and outdoors in areas with high infestations of Asian cockroaches.

Occupational Allergic Rhinoconjunctivitis and Asthma due to Fennel Seed

BACKGROUND A patient with complaints of rhinitis and asthma occurring at work presented for consultation. OBJECTIVES To evaluate the role of the foods and spices with which he worked, in the causation of his complaints, and to evaluate his immune reactivity to these materials. METHODS Allergy skin testing and in vitro RAST assays were carried out. After demonstrating specific reactivity to fennel, SDS-PAGE electrophoreses was carried out. RESULTS Positive skin tests to grass, ragweed, and freshly prepared fennel seed were found. Serum IgE antibodies to fennel were quite high. Immunoblotting studies showed reactions to two components in fennel extract as well as to components in mugwort, paprika, short ragweed and black pepper. CONCLUSION This case of occupational rhinitis and asthma in an atopic individual involves sensitivity to unique allergens in fennel, with molecular weights of 67 to 75 KD.

Regulation of TLR2 expression and function in human airway epithelial cells

Toll-like receptor (TLR1–6) mRNAs are expressed in normal human bronchial epithelial cells with higher basal levels of TLR3. TLR2 mRNA and plasma membrane protein expression was enhanced by pretreatment with Poly IC, a synthetic double-stranded RNA (dsRNA) known to activate TLR3. Poly IC also enhanced mRNA expression of adaptor molecules (MyD88 and TIRAP) and coreceptors (Dectin-1 and CD14) involved in TLR2 signaling. Additionally, mRNA expression of TLR3 and dsRNA-sensing proteins MDA5 and RIG-I increased following Poly IC treatment. In contrast, basal mRNA expression of TLR5 and TLR2 coreceptor CD36 was reduced by 77% and 62%, respectively. ELISA of apical and basolateral solutions from Poly IC-stimulated monolayers revealed significantly higher levels of IL-6 and GM-CSF compared with the TLR2 ligand PAM3CSK4. Pretreatment with anti-TLR2 blocking antibody inhibited the PAM3CSK4-induced increase in IL-6 secretion after Poly IC exposure. An increase in IL-6 secretion was also observed in cells stimulated with Alternaria extract after pretreatment with Poly IC. However, IL-6 secretion was not stimulated by zymosan or lipothechoic acid (LTA). These data demonstrated that upregulation of TLR2 following exposure to dsRNA enhances functional responses of the airway epithelium to certain (PAM3CSK4), but not all (zymosan, LTA) TLR2 ligands and that this is likely due to differences in coreceptor expression.

Variability of IgE protein measurement in cell-culture supernatants: results from a multicenter collaborative study

The sensitivity, specificity, and precision of immunoassays for quantitation of IgE in cell-culture supernatants were tested in a multicenter trial involving 22 laboratories. Fourteen coded test samples included cell-culture medium alone, culture medium with varying concentrations of polyclonal or myeloma IgE, and medium from unstimulated or pokeweed mitogen (PWM)-stimulated peripheral blood mononuclear cell (PBMC)-culture supernatants. Two laboratories reported measurable IgE in non-IgE-containing control samples. Although the IgE content of a single 0.50 ng/ml polyclonal IgE sample should have been measured easily by the claims of all laboratories, only 13 laboratories measured IgE in this sample in 22 of the 48 assays. Most laboratories could measure both polyclonal and myeloma IgE at 5.0 ng/ml; however, the IgE determinations for the myeloma proteins were nearer the predicted value. Although 15 laboratories found measurable IgE in the PWM-stimulated PBMC-culture supernatants from a single nonatopic donor, the levels did not differ significantly from that measured in unstimulated PBMC-culture supernatants. Three laboratories reported considerably higher IgE levels in the PWM-stimulated PBMC-culture supernatants than in other PBMC-culture supernatants. Only 13 laboratories could quantitate IgE in each of coded duplicate samples containing 0.50 ng/ml polyclonal IgE. These findings indicate a wide variability in the sensitivity, specificity, and precision of assays used to quantitate low levels of IgE protein. Investigators should be encouraged to make greater use of existing national and international reference materials in the standardization and performance of their IgE immunoassays.

Production of an International Reference Standard Alternaria Extract

As part of a program to establish international standards of selected allergens, 6 coded extracts of Alternaria were assessed in 6 laboratories by immunochemical, biochemical and physicochemical procedures. Direct RAST, RAST inhibition, quantitative skin tests and leukocyte histamine release were used to assign relative orders of potency to the 6 extracts. The composition and major allergen content was tested by thin-layer isoelectric focusing and quantitative immunoelectrophoresis (crossed immunoelectrophoresis and crossed radioimmunoelectrophoresis). Three laboratories determined the quantity of purified allergens in each of the preparations. In addition, source materials were sent to an expert Alternaria taxonomist for independent identification. The results showed considerable variation with respect to total allergenic potency and content of individual allergens. Source materials could not be confirmed as Alternaria in some instances. Based on fulfillment of written specifications and assay results, extract No. 6 was recommended by the Alternaria Working Group as the candidate international standard to the Steering Committee of the Allergen Standardization Subcommittee of the International Union of Immunological Societies.

Oxidative stress serves as a key checkpoint for IL-33 release by airway epithelium

Interleukin (IL)‐33 is implicated in the pathophysiology of asthma and allergic diseases. However, our knowledge is limited regarding how IL‐33 release is controlled. The transcription factor nuclear factor‐erythroid‐2‐related factor 2 (Nrf2) plays a key role in antioxidant response regulation.

Production of a proposed International Reference Standard Altenaria extract: II. Results of a collaborative trial

A lyophilized Alternaria extract prepared from a defined eight-strain source material was compared with three other Alternaria extracts to assess its potential suitability as an international standard (IS). Twenty-two laboratories in 12 different countries collaborated. Assay methods included RAST inhibition, quantitative immunoelectrophoresis, thin-layer isoelectric focusing, skin testing, leukocyte histamine release, and various other methods for thorough characterization of the extracts. In addition, three laboratories quantitated specific allergen in each extract. The proposed IS extract could be used to assign a relative potency to other test extracts. In separate studies, the proposed IS extract was demonstrated to be stable for at least 21 months when it is stored at -70 degrees C, -20 degrees C, and 4 degrees C.