RESUMO
BACKGROUND AND OBJECTIVES: The pathogenesis of IPF is unknown and it is hypothesized that immunological responses are involved. The purpose of this study was to detect autoantibodies in IPF patients and to identify the relevant antigens. METHODS: Sera from 37 healthy subjects and 22 IPF patients who had no clinical symptoms of collagen vascular disease were examined for immunostaining of A549 human type II cells and human lung tissue. Immunoprecipitation and proteome analysis were performed to identify the antigen. RESULTS: Fifty per cent of the patient sera and none of the control sera exhibited positive staining. Sera from 10 of the 22 IPF patients showed positive immunohistochemistry and immunoprecipitated a 110-kDa protein from the A549 cell lysate. Sera from only two of 41 patients with collagen vascular disease showed positive immunoreactivity. Proteome analysis using tandem mass spectrometry revealed that the protein was alanyl-tRNA synthetase. Transfection of cDNA of this enzyme into CHO-K1 cells conferred positive staining on these cells with the patients' IgG. The 135-kDa fusion protein consisting of 108-kDa enzyme protein and 27-kDa YFP from the cell lysate of the transfected cells was immunoprecipitated by the patient IgG. In addition, sera from IPF patients significantly inhibited the enzyme activity of alanyl-tRNA synthetase. CONCLUSION: A significant number of IPF patients possess circulating autoantibodies against alanyl-tRNA synthetase, suggesting the involvement of an autoimmune background in the pathogenesis of IPF.
Assuntos
Alanina-tRNA Ligase/imunologia , Autoanticorpos/análise , Fibrose Pulmonar/imunologia , Alanina-tRNA Ligase/metabolismo , Autoimunidade/imunologia , Células Cultivadas , Feminino , Humanos , Imunoglobulina G/imunologia , Imunoprecipitação , Masculino , Microscopia de Fluorescência , Pessoa de Meia-Idade , TransfecçãoRESUMO
BACKGROUND: The ras oncogene and the p53 tumor suppressor gene play important roles in the carcinogenic process of lung carcinoma. The authors evaluated whether alterations of the ras and p53 proteins may contribute to the development of lung carcinoma in patients with idiopathic pulmonary fibrosis (IPF) and whether such alterations may explain the high incidence of lung carcinoma among patients with IPF. METHODS: Lung tissues were obtained from 35 patients who had IPF without complications of lung carcinoma and from 36 patients who had IPF with complications of lung carcinoma. Altered expression of ras and p53 proteins was evaluated by immunohistochemistry, and mutations of both genes were evaluated by polymerase chain reaction-single strand conformation polymorphism and sequencing analyses. RESULTS: The frequency of expression of ras protein in type II alveolar pneumocytes was significantly greater in lung tissues from patients with IPF who had lung carcinoma compared with lung tissues from patients with IPF who did not have lung carcinoma (75% vs. 40%, respectively; P < 0.01). K-ras point mutation in codon 12 (GGT to GTT transversion) was detected in lung tissue with interstitial pneumonia, in which ras protein was overexpressed in type II alveolar pneumocytes obtained from 2 of 41 patients with IPF complicated by lung carcinoma, causing amino acid substitution (Gly to Val) in both patients. A p53 mutation was detected in three of six lung tissue samples from patients who had IPF lung with positive p53 immunoreactivity, and multiple mutations were detected in two samples. CONCLUSIONS: Expression of ras protein in type II alveolar pneumocytes and mutation in the codon 12 of K-ras gene in lung tissue may contribute to the induction of lung carcinoma in patients with IPF. Furthermore, the presence of multiple mutations in the p53 gene may explain the high incidence lung carcinoma in patients with IPF.
Assuntos
Neoplasias Pulmonares/patologia , Fibrose Pulmonar/patologia , Proteína Supressora de Tumor p53/genética , Proteínas ras/genética , Células 3T3 , Idoso , Idoso de 80 Anos ou mais , Animais , Sequência de Bases , Análise Mutacional de DNA , DNA de Neoplasias/química , DNA de Neoplasias/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Imuno-Histoquímica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos , Pessoa de Meia-Idade , Mutação , Reação em Cadeia da Polimerase , Polimorfismo Conformacional de Fita Simples , Fibrose Pulmonar/genética , Fibrose Pulmonar/metabolismo , Proteína Supressora de Tumor p53/biossíntese , Proteínas ras/biossínteseRESUMO
BACKGROUND: A field survey on farmer's lung disease (FLD) in a dairy farming community in the northernmost district of Japan has been in progress since 1978. METHODS: The correlation between the number of FLD occurrences year by year and dairy farming conditions and meteorological data were compared. RESULTS: Thirty-four FLD cases had occurred in a 20 years period. Average number of days below freezing during the harvest season the year prior to FLD occurrence were significantly smaller than other years (2.1 +/- 0.7 [SE] days, 4.6 +/- 0.7 days, P < 0.05, respectively). Average annual sum of the sunlight hours in the years before the years with FLD occurrence was significantly smaller than those without FLD occurrence (1457.1 +/- 114.0 hr, 1811.3 +/- 97.7 hr, P < 0.05, respectively) and was also significantly smaller for the sunlight hours during a harvest season (821.9 +/- 60.2 hr, 1023.2 +/- 52.7 hr, P < 0.05, respectively). CONCLUSIONS: Temperature and sunlight hours closely associated with the FLD occurrence.