Differentiation-induced cultured podocytes express endocytically active megalin, a heymann nephritis antigen.

BACKGROUND/AIMS: Megalin is a multiligand endocytic receptor expressed in a number of epithelia. In the Lewis rat kidney, podocytes, as well as proximal tubule cells, express megalin that acts as a pathogenic antigen for Heymann nephritis (HN), an experimental model of membranous nephropathy. To obtain a tool to investigate the molecular mechanisms of megalin-mediated endocytosis and the pathogenesis of HN, we examined whether a differentiation-inducible mouse podocyte cell line expressed endocytically active megalin. METHODS: Immunofluorescence and immunoprecipitation analyses with an anti-rat megalin antibody were carried out to investigate whether megalin was expressed in the differentiated and undifferentiated podocytes. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis was performed to elucidate whether the cells synthesize megalin mRNA. 125I-labeled receptor-associated protein (RAP), an endocytic ligand for megalin, was used for cellular internalization and degradation assays. RESULTS: Immunofluorescence, immunoprecipitation and RT-PCR analyses revealed that megalin was synthesized in both differentiated and undifferentiated cells and localized to the cell surfaces. Effective endocytosis of RAP via megalin was shown under the differentiated condition. CONCLUSION: Endocytically active megalin is expressed in differentiation-induced cultured podocytes. This cell line could be a useful tool for studies on megalin-mediated endocytosis and the pathogenesis of HN.

[Two cases of interstitial pneumonia with anti-Jo-1 antibodies in the absence of myositis].

We present two cases of interstitial pneumonia with anti-Jo-1 antibodies in the absence of myositis. The first patient was a 38-year-old woman and the second, a 59-year-old woman. Both patients were admitted to our hospital complaining of dry cough and dyspnea on effort. The diagnosis of interstitial pneumonia was made from chest radiography, computed tomography and surgical lung biopsy. Anti-Jo-1 antibodies, which were highly specific for polymyositis and dermatomyositis (PM/DM), were detected in both patients. However, the serum creatine kinase concentrations and electromyographic findings in both patients were normal, and no clinical signs (including muscle weakness, rash and arthralgia) were found. In the first patient, oral prednisolone (PSL) treatment (20 mg day) improved the interstitial pneumonia, but PSL has now been tapered to 17.5 mg day. In the second patient, oral PSL treatment (40 mg day) improved interstitial pneumonia, and the dose was tapered to 5 mg day. The second patient was followed for more than 10 years after treatment, but she has never shown any signs of clinical myositis. Further investigation will be required, because no pathophysiological relation between anti-Jo-1 antibodies and interstitial pneumonia with PM DM has yet been established.

Bronchoalveolar lavage fluid cells in mixed connective tissue disease.

OBJECTIVE: Patients with mixed connective tissue disease (MCTD) exhibit clinical features of systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and polymyositis and dermatomyositis (PM-DM). The objective of this study was to clarify differences in BAL findings and immunophenotypes of BAL fluid (BALF) cells of patients with interstitial lung disease associated with these diseases. METHODOLOGY: We were unable to recruit a sufficient number of SLE patients with lung disease. We compared immunophenotypes of lymphocytes and alveolar macrophages (AM) in BALF of 20 MCTD patients with those of 21 SSc and 27 PM-DM patients and tested the relationships between immunophenotypes and pulmonary function in MCTD. RESULTS: MCTD patients had a significantly higher CD4/CD8 ratio with more CD4 positive lymphocytes than PM-DM patients (P = 0.025). In AM phenotypes, MCTD patients had a significantly lower percentage of CD71 positive AM compared with SSc patients (P = 0.023). DLCO was negatively related to absolute numbers of CD8 positive lymphocytes (R = -0.517, P= 0.033). CONCLUSIONS: CD4 positive lymphocytes in BALF were increased in MCTD compared to PM-DM patients, while CD71 positive AM were decreased in MCTD compared to SSc patients. CD8 positive lymphocytes correlated negatively with DLCO measurements in MCTD patients.

[A case of interstitial pneumonia exacerbated by kampo-induced pneumonitis].

A 65-year-old woman who had complained of non-productive cough since May 1998 visited our hospital on November 5, 2000. She had been treated at another hospital with Kampo (Chinese herbal medicine), including Moku-boui-to, Bakumon-do-to, and Saiko-keishi-kankyo-to for chronic non-productive cough. Chest radiographs and CT films showed the reticular shadows that had been present in 1998, in both lower lung fields, and also demonstrated new reticular shadows in the right upper lung field and left lingular segment. Laboratory data revealed hypoxemia and pulmonary function tests revealed restrictive ventilatory disturbance, so she was admitted to our hospital on November 9, 2000. After the cessation of Kampo treatment, her symptoms disappeared, and the hypoxemia, restrictive disturbance, and reticular shadows in the chest radiograph gradually improved. Video-assisted lung biopsy specimens showed thickened alveolar walls with lymphocyte and eosinophil infiltration. A leukocyte migration test was positive for Moku-boui-to, Bakumon-do-to, and weakly positive for Saiko-keishi-kankyo-to. Although no challenge test for Kampo was performed, we diagnosed this case as interstitial pneumonia exacerbated Kampo-induced pneumonitis based on these clinical, laboratory and histological findings.

[Vasculitis and collagenous-vascular involvement in association with sarcoidosis].

Sarcoidosis is a systemic granulomatous disorder of unknown origin. It unusually complicates systemic vascular involvement. We concisely review clinico-pathological findings of vascular involvement, including granulomatous angitis and microangiopathy. The clinical features of sarcoidosis may mimic those of many rheumatic disorders and sarcoidosis may coexist with autoimmune diseases. We review both rheumatologic manifestations, including bone, joint, and muscle of sarcoidosis and immunological findings of autoimmune diseases complicated with sarcoidosis, including 2-case reports of Sjögren's syndrome and dermatomyositis/polymyositis.

Pulmonary involvement in mixed connective tissue disease: comparison with other collagen vascular diseases using high resolution CT.

PURPOSE: The purpose of this work was to compare the CT findings of lung involvement in patients with mixed connective tissue disease (MCTD) with those in patients with other CTDs: systemic lupus erythematosus (SLE), systemic sclerosis (SSc), and polymyositis and dermatomyositis (PM-DM). METHOD: CT scans of 35 patients with interstitial lung disease and associated MCTD were evaluated retrospectively. The CT assessment included determination of the findings and evaluation of whether the findings in MCTD were different from those in other CTDs. RESULTS: The frequency of ground-glass opacity in MCTD was significantly lower than in CTDs (p < 0.05). The frequency of honeycombing in MCTD was lower than in SSc (p < 0.05) and higher than in PM-DM (p < 0.005). Regarding the predominant CT patterns, the frequency of septal thickening in MCTD was significantly higher than in CTDs (p < 0.05). CONCLUSION: CT findings in MCTD were a combination of those in other CTDs.