Elevated exhaled nitric oxide in anaphylaxis with respiratory symptoms.

BACKGROUND: Anaphylaxis is a serious type I allergic reaction that occurs suddenly and can result in death, but it is sometimes difficult to differentiate from other diseases, and physicians must rely on symptoms alone for its diagnosis. Meanwhile, fractional exhaled nitric oxide (FeNO) concentration, used in assessing airway inflammation in bronchial asthma, is known to be affected by atopic disposition. The possible role of FeNO measurements was evaluated in patients with anaphylaxis. METHODS: FeNO was measured in 52 adult patients (17-78 years old, median age 41.5 years) in whom anaphylaxis occurred. These measurements were made within 24 h after onset and after about one month when the patients were symptom-free. In some of these patients, FeNO was measured a third time, two months or more after onset. RESULTS: The FeNO level in the 52 patients was not significantly different in measurement made within 24 h of onset of anaphylaxis and after one month. However, excluding 9 patients who also had asthma history, the FeNO level in the remaining 43 patients decreased significantly from within 24 h of onset (36.7 ± 27.5 ppb) to one month later (28.8 ± 19.5 ppb). Of these 43 patients, this phenomenon was evident in a group that had respiratory symptoms (31 patients), but it was not seen in a group that did not have respiratory symptoms (12 patients). CONCLUSIONS: Elevation of FeNO was related to respiratory symptoms observed in anaphylactic patients without asthma. Although the mechanism of increased FeNO level is unclear, its usefulness for diagnosis of anaphylaxis must be examined in prospective studies.

Th2-biased immune responses are important in a murine model of chronic hypersensitivity pneumonitis.

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-ß1 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.