Aiming at identifying biomarkers for bladder cancer, the serum proteome was explored in a pilot study through a profiling approach using protein arrays. Supervised analyses identified a panel 171 immunogenic proteins differentially expressed between patients with bladder cancer (n = 12) and controls without the disease (n = 10). The microanatomical expression patterns of novel immunogenic proteins, especially dynamin and clusterin, were found significantly associated with histopathologic variables and overall survival, as confirmed by immunohistochemistry using an independent series of bladder tumors contained in tissue microarrays (n = 289). Thus, the protein arrays approach has identified a panel of immunogenic candidates that may potentially play a role as diagnostic biomarkers, especially for muscle invasive disease. Moreover, the protein expression patterns of dynamin and clusterin in bladder tumors were shown to adjunct for histopathologic staging and clinical outcome prognosis.

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Anti-nucleosome (anti-chromatin) antibodies play a key role in the pathogenesis of systemic lupus erythematosus (SLE). The objective of the present study was to determine the clinical significance of anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in patients with SLE in relation to patients with positive nuclear antibodies and healthy controls. We measured anti-nucleosome (anti-chromatin) antibodies, anti-dsDNA antibodies and anti-histone antibodies in 70 patients with SLE, 35 antinuclear antibody (ANA)-positive subjects without autoimmune disease and 35 blood donors. All antibodies were determined by enzyme-linked immunosorbent assay (ELISA). We obtained the receiver operating characteristic (ROC) curve and the area under the curve (AUC) for each autoantibody. Likewise, we obtained the sensitivity, specificity and positive and negative likelihood ratios for each autoantibody. The highest AUC was obtained for anti-nucleosome (0.898) and the lowest AUC for a kit for anti-dsDNA (0.725). Stratification of the control group (ANA-positive subjects without autoimmune disease and blood donors) produced significant changes in the AUCs; all AUCs decreased when ANA-positive patients without autoimmune disease were considered as controls and all AUCs increased when blood donors were considered as controls. These effects were less marked in anti-dsDNA antibodies. We observed discrepancies between kits (anti-nucleosome and anti-chromatin and two for anti-dsDNA). The highest sensitivity for SLE was obtained for anti-nucleosome antibodies (86%) and the highest specificity was obtained for anti-dsDNA antibodies (90%). In conclusion, anti-nucleosome and anti-chromatin kits show different degrees of clinical accuracy due to the cut-off selected by the manufacturer. Once the kits with the best performance and the optimal cut-offs have been selected, anti-nucleosome antibodies and anti-dsDNA antibodies provide similar information in established SLE.

The measurement of anti-double-stranded DNA (anti-dsDNA) antibodies is a useful tool for the diagnosis and the follow-up of systemic lupus erythematosus (SLE). Anti-dsDNA antibodies are involved in the pathogenesis of lupus nephritis and they are, specially the high-avidity antibodies, the most specific antibodies associated with SLE nephritis and active SLE. The aim of the present study was to assess the clinical utility of an enzyme-linked immunosorbent assay (EUSA) that utilizes a circular double-stranded plasmid DNA as a nucleic acid source, adapted to an automated fluorescence immunoassay (EliA dsDNA, Pharmacia, Freiburg, Germany). Also, we compared this method with other immunoassays used in clinical laboratories. We have measured anti-dsDNA antibodies in the serum of 179 patients with a positive result for antinuclear antibodies (ANA). Seventy six sera were from SLE patients (14 men and 62 women), and the other 103 sera (from 20 men and 83 women) constituted the control group. This latter group includes nine Sjogren's syndrome patients, six patients with rheumatoid arthritis and 88 with various other diseases, including connective tissue diseases (n=34), hepatopathies (n= 17; 11 primary biliary cirrhosis and 6 autoimmune hepatitis), and 37 patients with nonautoimmune diseases (viral hepatitis, renal disease, diabetes, exanthema and hypertension). Methods used were "EliA dsDNA" (Pharmacia, Germany), "Varelisa dsDNA" (Pharmacia, Germany), Farr (Amersham, UK) and Chritidia luciliae immunofluorescence test (Vitro-Immun, Germany). We assessed sensitivity, specificity, positive predictive value and negative predictive value in the clinical study, and kappa index and scatter plots in the comparative study. The results show a low concordance between methods (kappa < 0.6). The evaluated EliA method shows a very good specificity for SLE (93.2%) and a good sensitivity for active SLE (70.8%).