Akira Akasawa

Evaluation of the staphylococcal exotoxins and their specific IgE in childhood atopic dermatitis

BACKGROUND Superantigenic exotoxins produced by Staphylococcus aureus and their specific IgE antibodies are thought to be important precipitating factors of atopic dermatitis (AD), but there are few reports evaluating these 2 factors at the same time. OBJECTIVE We examined whether the presence of the exotoxins sampled from the skin of patients with AD and the levels of anti-exotoxin IgE antibodies in their sera correlated with their severity of AD. METHODS Patients with mild-to-severe AD, 1 to 22 years of age, were evaluated by using Leicesters scoring system. Specific IgE antibodies against these exotoxins were determined by using ELISA. S aureus was isolated from 3 different areas of the skin. We examined whether the exotoxin (staphylococcal enterotoxin [SE]A, SEB, SEC, SED, and toxic shock syndrome toxin-1) could be detected. RESULTS The levels of SEB-specific IgE were correlated with the severity of AD. Five of 6 patients having very high SEB-specific IgE antibody titers were under 6 years of age, and SEB was most frequently isolated (41%). There was no difference in severity between patients with or without exotoxin-producing S aureus. The severity of 9 patients who had both exotoxin-producing S aureus on the skin and specific IgE antibody against the same exotoxin in sera was significantly higher than that of the other patients. CONCLUSIONS Anti-SEB IgE titers correlate well with the severity of AD. The presence of exotoxin-producing S aureus may precipitate AD through its specific IgE antibody.

Genome-wide association study identifies HLA-DP as a susceptibility gene for pediatric asthma in Asian populations.

Asthma is a complex phenotype influenced by genetic and environmental factors. We conducted a genome-wide association study (GWAS) with 938 Japanese pediatric asthma patients and 2,376 controls. Single-nucleotide polymorphisms (SNPs) showing strong associations (P<1×10−8) in GWAS were further genotyped in an independent Japanese samples (818 cases and 1,032 controls) and in Korean samples (835 cases and 421 controls). SNP rs987870, located between HLA-DPA1 and HLA-DPB1, was consistently associated with pediatric asthma in 3 independent populations (P combined = 2.3×10−10, odds ratio [OR] = 1.40). HLA-DP allele analysis showed that DPA1*0201 and DPB1*0901, which were in strong linkage disequilibrium, were strongly associated with pediatric asthma (DPA1*0201: P = 5.5×10−10, OR = 1.52, and DPB1*0901: P = 2.0×10−7, OR = 1.49). Our findings show that genetic variants in the HLA-DP locus are associated with the risk of pediatric asthma in Asian populations.

Plant defense–related enzymes as latex antigens☆☆☆★★★♢

BACKGROUND Latex allergy is an increasing hazard to people who frequently come into contact with latex products. Of interest concerning this immediate-type allergy is the cross-reactivity to various vegetable foods and pollen. Despite its high prevalence, no adequate explanation has been provided for the cross-reactive antigens. OBJECTIVE We have hypothesized that a series of plant defense-related proteins act as latex allergens, as well as vegetable food allergens. To evaluate this hypothesis, hydrolytic enzymes that are very likely to take on defensive roles in rubber trees were examined for their antigenicity. METHODS By applying chromatographic procedures, defense-related enzymes were separated from nonammoniated latex (NAL). Their antigenicity was examined by immunoblotting and ELISA with sera containing IgE antibodies to crude latex proteins. RESULTS Three kinds of hydrolytic enzymes (basic beta-1,3-glucanases [35, 36.5, and 38 kd], a basic chitinase/lysozyme [29.5 kd], and an acidic esterase [44 kd]) were separated from NAL. They were recognized by IgE antibodies from a significant number of patients allergic to latex. The basic beta-1,3-glucanases and the acidic esterase were also strongly recognized by IgE antibodies from several atopic subjects who were allergic to various vegetable foods rather than latex products. CONCLUSION It was ascertained that the three defense-related enzymes separated from NAL constituted part of the latex antigens. Taking together the well-known serologic or immunologic relationships and amino acid sequence similarities of defense-related proteins coming from phylogenetically distant plant species, we can suspect their universal antigenicity and cross-reactivity.

Pepsin-resistant 16-kD buckwheat protein is associated with immediate hypersensitivity reaction in patients with buckwheat allergy.

Background: Buckwheat is becoming popular in many countries as a health food and the incidence of buckwheat allergy is increasing in Asia. The ingestion of small amounts sometimes provokes an anaphylactic reaction. However, it remains controversial which is the major allergen responsible for such reactions. Methods: The patients whose sera are positive for buckwheat-specific IgE antibody measured by the CAP system fluorescein-enzyme immunoassay (CAP-FEIA) were classified into two subgroups depending on the history of immediate hypersensitivity reactions (IHR). Major buckwheat allergens were identified with immunoblotting, ELISA and N-terminal amino acid sequencing. Various treatments such as pepsin digestion were added to characterize the proteins. Results: We found that the 24-kD protein that had previously been reported to be a major allergen reacted to IgE antibodies present in sera from almost all subjects (19/20) regardless of symptoms. On the other hand, 16- and 19-kD proteins were bound with IgE antibodies present in sera from 9 of the 10 patients with IHR including 8 patients with anaphylaxis but not in sera from buckwheat-specific IgE-positive subjects without IHR. After pepsin treatment, the 16-kD protein but not the 19- and 24-kD proteins remained undigested and preserved the capacity of IgE binding. This pepsin-resistant 16-kD protein had no homology with the 24-kD protein by the N-terminal amino acid sequencing. Conclusions: The 16-kD buckwheat protein was resistant to pepsin digestion and appeared to be responsible for IHR including anaphylaxis, while the pepsin-sensitive 24-kD protein was responsible for CAP-FEIA but not IHR.

Identification of highly expressed genes in peripheral blood T cells from patients with atopic dermatitis.

Background: Analysis of genes that are differentially expressed in patients with atopic dermatitis (AD) and normal individuals will provide important information on the underlying molecular pathogenetic mechanisms of AD. Methods: Transcript of freshly isolated peripheral blood T cells from 59 individuals were analyzed with a fluorescent differential display (FDD) method. Ninety-two differentially expressed genes were identified in this manner. Additionally, real-time quantitative RT-PCR was employed to investigate the expression of the FDD-selected genes and also genes related to T cell function. Results: A number of genes, including CC chemokine receptor 4, T cell-specific tyrosine kinase (Emt/Itk), integrin β1, integrin α6, IQGAP1 and MAR/SAR DNA-binding protein (SATB1), were shown to be more highly expressed in patients with moderate and/or severe AD than in controls or patients with mild AD. Because the products of these upregulated genes influence chemotaxis, adhesion, migration and Th2 polarization, it is suggested that in more severe AD, circulating T cells may function differently in this regard. Several other genes, the role of which in T cell function is currently unknown, were also found to be differentially expressed in AD. These included the heat shock protein 40 and vasopressin-activated calcium-mobilizing receptor 1. Conclusion: The upregulated genes identified in this work may serve as useful markers for moderate to severe AD as opposed to normal or mild AD and also as markers indicating progression to more severe AD. Further functional characterization will provide a better understanding of the pathophysiology of circulating T cells in AD.

Nationwide Cross-Sectional Population-Based Study on the Prevalences of Asthma and Asthma Symptoms among Japanese Adults

Background: Asthma is a common respiratory disease worldwide. However, few reports are available on the prevalences of asthma and asthma symptoms among Asian subjects. Methods: To determine the prevalences of asthma and asthma symptoms among Japanese subjects, we performed a nationwide cross-sectional, population-based study on Japanese adults aged 20–79 years. Ten areas spread throughout the country were randomly selected. Door-to-door or postal surveys were performed using a translated version of the European Community Respiratory Health Survey questionnaire. Results: The survey was completed by 23,483 participants. The overall response rate was 70.6%. The prevalences of wheeze and current asthma among all participants aged 20–79 years were 10.1% (95% CI: 9.7–10.5%) and 4.2% (95% CI: 4.0–4.5%), respectively. The prevalences among young adults aged 20–44 years were 9.3% (95% CI: 8.7–9.9%) and 5.3% (95% CI: 4.8–5.8%), respectively. The prevalence of current asthma was highest in females aged 30–39 years in comparison with the other gender and age groups. Conclusions: This nationwide study determined the prevalences of asthma and asthma symptoms among Japanese adults. The results provide fundamental information on the respiratory health of Japanese adults.

Antigen-specific T-cell responses in patients with non-IgE-mediated gastrointestinal food allergy are predominantly skewed to TH2

Age (mo) 12 38.0 (26.5-60.0) 65 2.0 (1.0-4.0) Male/female sex 12 7/5 65 40/25 Day of onset 12 — 65 32.5 (7.0-115.5) Symptoms at onset Vomiting 12 0% (0/12) 65 53.8% (35/65) Bloody stool 12 0% (0/12) 65 47.7% (31/65) Diarrhea 12 0% (0/12) 65 47.7% (31/65) Failure to thrive 12 0% (0/12) 65 38.4% (22/65) Lethargy 12 0% (0/12) 65 38.4% (22/65) Fever 12 0% (0/12) 65 18.5% (12/65) Eczema 12 100% (12/12) 65 7.7% (5/65) Wheeze 12 33.3% (3/12) 65 0% (0/65) Laboratory data Milk-specific IgE (IU/mL) 12 56.95 (11.74-90.8) 65 <0.34 (<0.34)

The prevalence of rhinitis and its association with smoking and obesity in a nationwide survey of Japanese adults

Rhinitis is a common disease, and its prevalence is increasing worldwide. Several studies have provided evidence of a strong association between asthma and rhinitis. Although smoking and obesity have been extensively analyzed as risk factors of asthma, associations with rhinitis are less clear.

Exercise-Induced Asthma is Associated with Impaired Quality of Life Among Children with Asthma in Japan

BACKGROUND Asthma is the most common chronic diseases in school-aged children in Japan. It is important to consider health-related quality of life (QoL) among children with chronic diseases when treatment decisions are made. METHODS A school-based survey was conducted in randomly selected public schools in Tokyo by using a KINDL questionnaire for evaluating QoL and the international study of asthma and allergy on childhood (ISAAC) questionnaire, which is designed for comparing the asthma prevalence in various countries, from May to June in 2005. We recruited approximately 10% of the total children 6-7-years-old and 13-14-years-old living in Tokyo for sampling. RESULTS Response rate of this questionnaire was 86% (22,645 children) in the 6-7-year-old group and 64% (12,879 children) in the 13-14-year-old group. Comparing asthmatics with non-asthmatics in the same age, QoL of children with asthma was significantly impaired. The severity of QoL of children with asthma was significantly impaired. QoL of children with exercise-induced asthma (EIA) were more significantly impaired than ones without EIA and showed lower scores in the categories of physical functioning, emotional and school activities than those without EIA. Of note, QoL was more impaired in the EIA-positive group among severe asthmatics, suggesting that QoL of children with even severe asthma could be improved when EIA is appropriately controlled. CONCLUSIONS Existence of EIA among asthmatic children most strongly impairs their QoL. We should be more cautious about the management of EIA.

High-Density Oligonucleotide Array Analysis of mRNA Transcripts in Peripheral Blood Cells of Severe Atopic Dermatitis Patients

Background: There are few laboratory tests for evaluating atopic dermatitis (AD) with the exception of IgE levels or the eosinophil count. We attempted to identify new diagnostic markers by screening the genome-wide expression of transcripts in peripheral blood mononuclear cells (PBMC). Methods: For this study, we enrolled 7 nonatopic healthy volunteers, 5 AD patients who responded well to treatment and 6 who responded poorly. We compared genome-wide transcript levels in PBMC derived from patients with severe AD and healthy volunteers using high-density oligonucleotide arrays (GeneChip, Affymetrix). After the first screening with GeneChip, we employed real-time quantitative PCR to confirm differential expression levels. Results: Screening with GeneChip showed that the levels of a total of 92 transcripts increased at least 3-fold in one population compared to another. After further evaluation of these genes with real-time quantitative PCR, the levels of 4 transcripts were confirmed to be significantly different in PBMC from AD patients compared to controls, namely IFN-γ, TRAIL (TNF-related apoptosis-inducing ligand), ISGF-3 (STAT1) and defensin-1. With the exception of IFN-γ, none of these genes has previously been implicated in AD pathology. Conclusion: These 4 transcripts in PBMC are expected to be useful markers for evaluating AD.