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In this review, we examine house dust and its effect on inhabitants' health. Residential house dust includes components from plants, pollens, microorganisms, insects, skin flakes, hairs and fibers. It also includes materials contaminated with chemicals from combustion, furniture, interior materials, electronics, cleaning agents, personal care products. Nowadays, most people spend their time indoors. Thus, dust is an important medium of exposure to pollutions. According to United States Environmental Protection Agency Exposure Factors Handbook, the estimated amount of dust ingestion is 30 mg/day for adults, and 60 mg/day for children over 1 year of age. Since 2003, we have been conducting epidemiological studies to find the association between the indoor environment and the inhabitants' health. The levels of mite allergens, endotoxins, and β-1,3-d-glucan in house dust were measured as biological factors. Semi volatile organic compounds (SVOC) such as phthalates and phosphate flame retardants (PFRs) in dust were also analyzed. As a result, we found that the ORs (95%CI) of nasal and optical symptoms of sick building syndrome (SBS) were 1.45 (1.01-2.10) and 1.47 (1.14-1.88), respectively, when there was a 10-fold increase in the levels of mite allergens. There was no association of mite allergens with allergies. Endotoxins and β-1,3-d-glucan did not show any association with SBS. Regarding SVOC, increased levels of phthalates and PFR increased the risk of allergies. The association between phthalates and increased risk of allergies was clearer among children than adults. There were no gold standards of dust sampling and pretreatment methods. Thus, caution is needed when comparing findings of various studies. Methods should accurately reflect exposure levels.

Aspergillus is a medically important fungal genus that causes a life-threatening infection known as aspergillosis in immunocompromised patients. β-1,3-Glucan is detected in the plasma of patients with aspergillosis and appears to be useful for the diagnosis of aspergillosis. In this study, we cultured Aspergillus spp. in a chemically defined liquid medium and prepared an Aspergillus water-soluble fraction (ASWS) from the culture supernatants. ASWS was found to be primarily composed of polysaccharides and proteins. Nuclear magnetic resonance analysis suggested that ASWS is a complex carbohydrate, consisting of α-1,3-glucan, β-1,3-glucan, galactomannan, and protein. The ASWS from Aspergillus fumigatus showed limulus factor G activity, whereas zymolyase-treated ASWS did not. ASWS was eliminated from the blood more rapidly than Aspergillus solubilized cell wall β-glucan. We analyzed the reactivity of human immunoglobulin towards ASWS by an enzyme-linked immunosorbent assay. Anti-ASWS antibodies were detected in human sera, with titers differing among individuals. This study demonstrated that the ASWS corresponds to the limulus factor G-activating substance found in the blood of patients with aspergillosis.

In order to establish the reliable cut-off value of galactomannan (GM) antigen as well as that for beta-D-glucan for CNPA diagnosis, we conducted the following study. From 2001 to 2008, in a total of 1511 patients we measured GM and anti-aspergillus antibody simultaneously. These patients had chronic pulmonary disease including old tuberculosis, nontuberculous mycobacteriosis, COPD, and had bullous lung, interstitial lung disease or were suspected to have suspected to have interstitial lung disease. We designated cases as probable CNPA when the sample represented a positive anti-aspergillus antibody. We then analyzed the sensitivity and specificity according to various GM antigen values. When using the GM antigen cut-off value at 0.5, the sensitivity and specificity for CNPA were 63.4% and 68.6% respectively. Using 1.0 for cut-off value resulted in the better specificity for CNPA diagnosis. Similar analysis was performed on beta-D-glucan for CNPA diagnosis. When using D-glucan cut-off value as 20 pg/ml, the sensitivity and specificity for CNPA. These results indicate that the cut-off value of serological examination for infectious disease should be considered by the type of disease.

We had reported that the rate of non-specific reaction in measurement of (1-->3)-beta-D-glucan was decreased by improvement of the alkaline pretreatment reagent of Fungitec G-test MK (MK assay). To compare the clinical usefulness between conventional MK assay and new MK assay using improved alkaline pretreatment reagent, 121 plasma samples were tested. The sensitivity, specificity, positive predictive value (PPV), negative predictive values (NPV) in conventional MK assay were 91.7%, 85.3%, 44.0% and 98.8%, respectively. Those in new MK assay were 75.0%, 91.6%, 52.9% and 96.7%, respectively. On the other hand, area under the curve (AUC) of receiver operating characteristic (ROC) analysis in conventional and new MK assay was 0.9175 and 0.9123 without a significant difference. It has been recognized that the sensitivity in conventional MK assay is higher than those in other beta-glucan assays. Then, the specificity of new MK assay was improved by using improved alkaline pretreatment reagent, without decreasing the sensitivity. Thus, the present findings indicate that the new MK assay is clinically quite useful.

A farmer and his son, who treated straw in a cowshed, were admitted to our hospital because of severe dyspnea during summer time. Their chest X-ray films revealed bilateral reticulonodular shadows in the middle to lower lung fields. Bronchoalveolar lavage (BAL) fluid analyses showed a high proportion of lymphocytes and an increased CD4/8 ratio. They were diagnosed with farmer's lung and treated with pulse therapy with methylprednisolone and tapering of steroid. Hypoxemia and interstitial shadow improved, though the farmer relapsed one day after getting home. Immune precipitation showed positive reactions against Aspergillus fumigatus, Aspergillus terreus and Nocardiopsis alba. Their beta D-glucan levels in BAL fluid were higher than those of healthy normal volunteers, whereas their beta D-glucan levels in serum were below the detection levels. Ventilation of the cowshed and wearing a mask should prevent recurrence of the disease.