ABSTRACT
<p><b>BACKGROUND</b>Interstitial lung disease (ILD) is a serious lung complication in polymyositis (PM) and dermatomyositis (DM) which affects prognosis and requires a more aggressive approach in therapy. This study investigated the prevalence, characteristics, predictive factors and unfavourable prognostic factors of ILD in newly diagnosed PM, DM and amyopathic DM (ADM).</p><p><b>METHODS</b>From January 2000 to December 2008, the medical records of 197 consecutive PM and DM patients at the Second Affiliated Hospital of Sun Yat-Sen University were reviewed excluding overlapping, juvenile, and malignancy-associated cases. The patients were assigned to an ILD (69 patients) and a non-ILD group (128 patients). The clinical features, laboratory findings, and prognosis were compared.</p><p><b>RESULTS</b>The multivariate analysis indicated that older age at onset (OR 1.033, 95%CI 1.009 - 1.058, P = 0.007), fever (OR 4.109, 95%CI 1.926 - 8.767, P < 0.001) and arthritis/arthralgia (OR 2.274, 95%CI 1.101 - 4.695, P = 0.026) were the independent predictive factors for developing ILD in PM/DM after excluding anti-Jo-1. Regarding anti-Jo-1, fever (OR 4.912, 95%CI 2.121 - 11.376, P < 0.001) was associated with ILD. Poor survival in ILD patients was associated with ILD clinical subset (RR 0.122, 95%CI 0.049 - 0.399, P < 0.001), ADM/DM/PM-ILD (RR 0.140, 95%CI 0.031 - 0.476, P = 0.002), cardiac involvement (RR 4.654, 95%CI 1.391 - 15.577, P = 0.013) and serum albumin level (RR 0.910, 95%CI 0.831 - 0.997, P = 0.042).</p><p><b>CONCLUSIONS</b>Patients who presented with fever tended to have a higher frequency of PM/DM-associated ILD. A Hamman-Rich-like presentation, ADM-ILD, cardiac involvement and hypoalbuminemia were poor prognostic factors in ILD-PM/DM.</p>
Subject(s)
Adult , Aged , Female , Humans , Male , Middle Aged , Dermatomyositis , Logistic Models , Lung Diseases, Interstitial , Mortality , Polymyositis , Prognosis , Proportional Hazards Models , Retrospective StudiesABSTRACT
<p><b>BACKGROUND</b>Skin lesions are common manifestations in systemic lupus erythematosus (SLE). It is still unknown what the definite pathogenesis of skin involvement was and whether DNA participated in it. Our study was designed to explore the pathogenetic role and nature of nuclear antigen (DNA) deposited in the skin lesions of patients with SLE.</p><p><b>METHODS</b>Thirty skin samples from patients with SLE and 2 normal skin samples were studied. Extracellular DNA was evaluated by indirect immunofluorescence methods. The deposited immune complexes were extracted by cryoprecipitation, and DNA was then isolated with phenol and chloroform. DNA fragment sizes were detected by agarose gel electrophoresis. Finally, 8 different probes were used to analyze the origin of these DNA molecules using Dot hybridization.</p><p><b>RESULTS</b>Extracellular DNA staining was found only in skin lesions, mainly those located in the basement membrane zone, vascular wall, and hair follicle wall. Normal skin and non-lesion SLE skin showed no fluorescence at locations outside the nuclei. There were no differences in the rate and intensity of extracellular DNA staining when comparing active phase to remission phase patients. No relationship was found between extracellular DNA and circulating anti-dsDNA antibodies. Deposited DNA fragments clustered into four bands of somewhat discrete sizes: 20 000 bp, 1300 bp, 800-900 bp, 100-200 bp. Small sized fragments (100-200 bp) were positively correlated with disease activity (P < 0.05, r = 0.407). Dot hybridization showed significant homology of the various extracellular DNA fragments examined with human genomic DNA, but not with DNA from the microorganisms and viruses we examined. There were also homologies between DNA samples from different individuals.</p><p><b>CONCLUSIONS</b>DNA and its immune complexes may contribute to the pathogenesis of skin lesions in SLE. These DNA molecules range in size from 100 bp to 20 kb and may be endogenous in origin.</p>