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Background The reaction of specific antibodies and sensitized lymphocytes to antigens is important in hypersensitivity pneumonitis (HP). However, there are no known studies evaluating the utility of the lymphocyte proliferation test (LPT) or specific antibodies to avian antigens in diagnosing bird-related HP. In this study, we examined the sensitivity and specificity of these two tests. Methods Patients with acute bird-related HP ( n =10), chronic bird-related HP ( n =35), acute summer-type HP ( n =14), and other interstitial pneumonia (IP) ( n =76) were evaluated. The optimal cutoff values were determined by receiver operating curve (ROC) analyses of specific antibodies in serum and bronchoalveolar lavage fluid (BALF), and by conducting the LPT on mononuclear cells in peripheral blood and BALF. Results The sensitivity and specificity of the antibodies were 80–100% and 92–100% in acute bird-related HP, and 26–79% and 73–93% in chronic bird-related HP, respectively. The sensitivity and specificity of the LPT were 50–100% and 100% in acute bird-related HP, and 46% and 91% in chronic bird-related HP, respectively. Conclusions Specific antibodies and the LPT are quite useful for diagnosing acute bird-related HP. The presence of specific antibodies in BALF and the results of LPT with peripheral blood mononuclear cells are particularly useful for diagnosing chronic bird-related HP.

To clarify the clinical symptoms of the influenza A virus during the 2009 pandemic influenza outbreak, we describe the clinical features of outpatients diagnosed with type A influenza by use of the rapid influenza diagnostic test (RIDT) from September to December 2009. Questionnaires were used to collect prospective data on 1,122 cases with influenza-like illness at our medical institutions. The independent predictors of influenza A virus were identified on the basis of demographic features and the clinical symptoms of the patients who tested positive for influenza A virus in the RIDT test. Of the 1,122 cases tested, 389 (34.7%) were positive for the influenza A virus. The median age of the influenza-positive patients was 14, and 58.9% of the patients were male. The symptoms fever, cough, rhinorrhea, and headache were statistically dominant. A history of recent contact with persons suffering from influenza or influenza-like illness at home, school, or in the workplace was significantly more common in the positive group than in the negative group. Pneumonia was observed in 2 (0.5%) of the positive patients, but the symptoms were only severe enough to require hospitalization in 1 of the 2. No deaths were observed among the 389 RIDT-positive patients. Although the spread of influenza A virus was both rapid and extensive, mainly among children under the age of 18, it seemed to be mild. Appropriate interpretation of the RIDT on the basis of recent clinical information, and early treatment with antiviral drugs might help to prevent severe illness from influenza pandemics in the future.

Background: Chronic hypersensitivity pneumonitis (HP) can lead to irreversible pulmonary fibrosis. A good animal model is essential to elucidate the mechanisms of this disease. We previously reported that a Th2 predominance may play an important role in the fibrogenesis in chronic HP patients. A study was undertaken to evaluate whether Th2-biased immune responses were crucial during the processes of lung fibrosis in a murine model of chronic HP. Methods: Instillation of pigeon dropping extracts (PDE) was conducted 3 days a week for 6 or 12 weeks in C57BL/6, BALB/c and A/J mice to establish models of chronic HP. We evaluated the histopathological features, immunohistochemistry, collagen content, bronchoalveolar lavage fluid (BALF) profiles and Th1/Th2 cytokines in BALF or lung tissue with RT-PCR and ELISA. Results: Thickening of the alveolar walls and structural alterations were observed only in the A/J mice after 12 weeks of exposure to PDE. The fibrosis scores were significantly increased in 12-week A/J mice compared to those in the other strains. Immunohistochemistry evaluation showed that PDE was engulfed by alveolar macrophages that were incorporated into the alveolar septa of 12-week A/J mice. Interleukin (IL)-4 mRNA increased significantly in 6- and 12-week A/J mice. IL-13 mRNA showed a significant increase in 12-week A/J mice compared with 6-week A/J mice. TGF-β1 mRNA at 12 weeks was significantly increased in A/J mice compared with the other groups. Conclusion: Th2-biased genetic backgrounds may play an important role in fibrosing processes in the present chronic HP model.

Hypersensitivity pneumonitis (HP) is an immune mediated lung disease induced by the repeated inhalation of a wide variety of antigens. Bird-related hypersensitivity pneumonitis (BRHP) is one of the most common forms of HP in human and results from the inhalation of avian antigens. The findings of a recent clinical analysis suggest that in addition to Th1 factors, the levels of interleukin(IL)-17 and IL-17-associated transcripts are increased in the setting of HP, and that both IL-17A and neutrophils are crucial for the development of pulmonary inflammation in murine models of HP. Our objectives were to investigate the roles of IL-17A and neutrophils in granuloma-forming inflammation in an acute HP model. We developed a mouse model of acute BRHP using pigeon dropping extract. We evaluated the process of granuloma formation and the roles of both IL-17A and neutrophils in a model. We found that the neutralization of IL-17A by the antibody attenuated granuloma formation and the recruitment of neutrophils, and also decreased the expression level of chemokine(C-X-C motif) ligand 5 (CXCL5) in the acute HP model. We confirmed that most of the neutrophils in the acute HP model exhibited immunoreactivity to the anti-IL-17 antibody. We have identified the central roles of both IL-17A and neutrophils in the pathogenesis of granuloma formation in acute HP. We have also assumed that neutrophils are an important source of IL-17A in an acute HP model, and that the IL-17A-CXCL5 pathway may be responsible for the recruitment of neutrophils.