Cockroach allergy

Association between Cockroach-specific Immunoglobulin E and periodontitis in Korean male adults Based on Korean National Health and Nutrition Examination Survey

Periodontitis is an inflammatory disease affecting the tooth supporting tissues (periodontium) and associated with chronic diseases such as cardiovascular disease and insulin resistance. However, there has been no nation-wide population based epidemiologic study regarding any association between periodontitis and serum IgE. Among the 8,958 participants in the 2010 Korean National Health and Nutrition Examination Survey (KNHANES V-1), 1,731 adults aged 19 to 64 who had measured serum IgE were included in the analysis. Dentists examined the periodontal status of the participants. Multiple logistic regression analyses were used to evaluate the odds ratio of periodontitis in association with total IgE and specific IgE to cockroach and house dust mite. In males, total IgE showed a positive correlation with the presence of periodontitis. The participants in the highest tertile of cockroach specific IgE (T3, >31.6 kU/L) had a significantly increased risk of periodontitis (OR = 2.108; 95% CI, 1.233–3.606). In females, the inverse association occurred between total IgE and periodontitis (OR = 0.409; 95% CI, 0.200–0.839). The present study firstly demonstrated the association between periodontitis and serum IgE, using the Korean nationwide, population-based, cross-sectional health examination and survey. This study suggested a positive correlation between periodontitis and cockroach-specific IgE in Korean male adults.

IgE-Binding Epitope Mapping and Tissue Localization of the Major American Cockroach Allergen Per a 2

Purpose

Cockroaches are the second leading allergen in Taiwan. Sensitization to Per a 2, the major American cockroach allergen, correlates with clinical severity among patients with airway allergy, but there is limited information on IgE epitopes and tissue localization of Per a 2. This study aimed to identify Per a 2 linear IgE-binding epitopes and its distribution in the body of a cockroach.

Methods

The cDNA of Per a 2 was used as a template and combined with oligonucleotide primers specific to the target areas with appropriate restriction enzyme sites. Eleven overlapping fragments of Per a 2 covering the whole allergen molecule, except 20 residues of signal peptide, were generated by PCR. Mature Per a 2 and overlapping deletion mutants were affinity-purified and assayed for IgE reactivity by immunoblotting. Three synthetic peptides comprising the B cell epitopes were evaluated by direct binding ELISA. Rabbit anti-Per a 2 antibody was used for immunohistochemistry.

Results

Human linear IgE-binding epitopes of Per a 2 were located at the amino acid sequences 57-86, 200-211, and 299-309. There was positive IgE binding to 10 tested Per a 2-allergic sera in 3 synthetic peptides, but none in the controls. Immunostaining revealed that Per a 2 was localized partly in the mouth and midgut of the cockroach, with the most intense staining observed in the hindgut, suggesting that the Per a 2 allergen might be excreted through the feces.

Conclusions

Information on the IgE-binding epitope of Per a 2 may be used for designing more specific diagnostic and therapeutic approaches to cockroach allergy.

Insect and arachnid hypersensitivity

Insect hypersensitivity reactions can have a large number of clinical presentations. The majority of reactions are pruritic and involve the short- or sparsely haired areas of the body. Most are associated with eosinophilic infiltration into the skin, often in a perivascular pattern. The diagnosis may be based on compatible clinical signs and improvement with aggressive insect control and, in some cases, confirmation via provocative exposure. Intradermal, prick, or serum testing for allergen-specific IgE can be used to document the presence of reaginic antibodies against insect allergens. Treatments include avoidance, aggressive insect control, and symptomatic support; in some cases, immunotherapy may be useful in decreasing the severity of clinical reactions to insects.

Molecular Characterization of American Cockroach Tropomyosin (Periplaneta americana Allergen 7), a Cross-Reactive Allergen

Inhalation of allergens produced by the American cockroach (Periplaneta americana) induces IgE Ab production and the development of asthma in genetically predisposed individuals. The cloning and expression in Escherichia coli of P. americana tropomyosin allergen have been achieved. The protein shares high homology with other arthropod tropomyosins (80% identity) but less homology with vertebrate ones (50% identity). The recombinant allergen was produced in E. coli as a nonfusion protein with a yield of 9 mg/l of bacterial culture. Both natural and recombinant tropomyosins were purified by isoelectric precipitation. P. americana allergen 1 (Per a 1) and Per a 7 (tropomyosin) are to date the only cross-reacting allergens found in cockroaches. ELISA and Western blot inhibition experiments, using natural and recombinant purified tropomyosins from shrimp and cockroach, showed that tropomyosin induced cross-reactivity of IgE from patients allergic to these allergens, suggesting that this molecule could be a common allergen among invertebrates.

Environmental control of indoor air pollution

Indoor air pollution is becoming an increasing problem in industrialized countries. Most people spend their time indoors which results in chronic exposure to indoor allergens and irritants. New products have been introduced to the environment to which humans are not immunologically adapted. This article describes the main sources of indoor air pollution and the best ways to control exposure to indoor air pollutants.