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Summary Background Pulmonary fibrosis is a manifestation of microscopic polyangitis (MPA), and often precedes the detection of MPA. The prevalence and sequence of myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) and MPA in patients initially diagnosed with idiopathic pulmonary fibrosis (IPF) have not been precisely elucidated. Methods We enrolled 61 consecutive patients with IPF and measured the MPO-ANCA titers at initial presentation and during the follow-up period. Clinical, radiologic and histologic features of MPO-ANCA-positive cases were examined. Results Of 61 patients, 3 (4.9%) had positive MPO-ANCA titers at the initial presentation of IPF. During the disease course, MPO-ANCA-positive conversion occurred in 6 patients and the prevalence of ANCA increased to 14.8%. Among the nine patients positive for MPO-ANCA, two patients developed MPA during follow-up. Histologic features of MPO-ANCA-positive pulmonary fibrosis were compatible with the usual interstitial pneumonia pattern in which alveolar hemorrhage and capillaritis were not observed. The patients with MPO-ANCA-positive conversion showed increased percentages of bronchoalveolar lavage eosinophils and more frequent complication of pulmonary emphysema compared to those with MPO-ANCA-negative IPF. Conclusions The findings of the present study demonstrated that patients with an initial diagnosis of IPF occasionally acquire MPO-ANCA, which develops to MPA during the disease course of IPF. The presence of pulmonary eosinophilia and low attenuation areas on computed tomography scans might be predictive of MPO-ANCA positive conversion.

Summary A 36-year-old man was transferred to the hospital for further evaluation of pulmonary infiltration. A diagnosis of acute eosinophilic pneumonia (AEP) was confirmed by clinical symptoms, bronchoalveolar lavage, and computed tomography findings. Skin tests with fungal antigens were performed by intradermal injection. Both the Arthus (8h) and delay (24h)-type skin tests were positive for only Candida albicans . A lymphocyte-stimulating test was also positive for C. albicans . The etiology of the AEP was confirmed by a C. albicans inhalation provocation test. In addition, peripheral blood mononuclear cells obtained from the patient produced Interleukin-5 following C. albicans stimulation. This is the first report of C. albicans as a probable cause of AEP. Evaluation of allergy to C. albicans should be performed in AEP before diagnosing the cause as idiopathic.

A disintegrin and metalloprotease (ADAM) family members, characterized by a metalloprotease and a disintegrin domain, are membrane-anchored glycoproteins involved in proteolysis and cell adhesion. ADAM8 is specifically induced in the experimental murine asthmatic lung. To evaluate novel pathways involved in asthma pathogenesis, using ADAM8 transgenic mice (ATMS2) in a murine model of asthma. Massive cellular infiltrates in peribronchovascular and interstitial lesions were observed in control mice, while in ATMS2 mice there were only occasional. Vascular cell adhesion molecule (VCAM-1) is involved in specific eosinophil adhesions via alpha4beta1 integrin. VCAM-1 shedding was mediated by the ADAM8 metalloprotease. Endothelial cell shedding of VCAM-1 was increased in ATMS2-stimulated human umbilical endothelial cells. ADAM8-mediated shedding of VCAM-1 might be important for the suppression of experimental asthma. Our data suggest that ADAM8 is a useful therapeutic target.