Prevalence of anti-CCP antibodies in systemic sclerosis

Joint involvement in systemic sclerosis (SSc) commonly occurs as arthralgias, while a true arthritis is less frequent. The most common arthritis developing in SSc is rheumatoid arthritis (RA) and its diagnosis may be misled by concomitant joint contracture or tendon sheath involvement due to SSc. Anti-citrullinated cyclic peptide (CCP) antibodies are an emerging tool to diagnose RA and have shown to be more specific than rheumatoid factor. We assessed the prevalence of anti-CCP antibodies in SSc patients and evaluated their sensitivity and specificity for associated RA. Searching for RF and anti-CCP antibodies and joint examination were carried out in sixty consecutive SSc patients. Hands and feet standard x-rays were performed in patients complaining with arthralgia and/or arthritis. Six out of sixty (10%) SSc patients had RA according to 1987 ARA revised criteria. Anti-CCP were detected in 5 patients (sensitivity 83%) and RF was present in all RA patients (sensitivity 100%). However, anti-CCP antibodies had a much higher specificity (94%) than RF (41%) for RA. Our study suggests that anti-CCP antibodies are a useful test to identify patients with SSc having also RA. This is crucial in the management of SSc because may allow an adequate therapy of RA and prevent further joint damage in patients who already have a poor quality of life

Serological epitope profile of anti-Ro52-positive patients with systemic autoimmune rheumatic diseases

Background: Ro52 is an interferon-inducible protein of the tripartite motif family. Antibodies against Ro52 have been described in patients with different autoimmune diseases, such as systemic lupus erythematosus and Sj\uf6gren's syndrome, that are often associated with anti-Ro60 antibodies. The Ro52 autoantigen is extraordinarily immunogenic, and its autoantibodies are directed against both linear and conformational epitopes. The aim of this study was to evaluate the prevalence of antibodies to the five Ro52 domains, as well as to Ro52 176- to 196-amino acid (aa) and 200-239-aa peptides, in different systemic autoimmune rheumatic diseases (SARDs). We also aimed to verify whether antibodies to a single domain or domain association could increase their diagnostic specificity for any SARD. Methods: Serum samples were obtained from 100 anti-Ro52 antibody-positive patients with SARDs and from 68 controls (50 healthy donors and 18 patients with other autoimmune or allergic diseases). A special line immunoassay was created containing a full-length Ro52 antigen expressed in insect cells using the baculovirus system, five recombinant Ro52 antigen fragments [Ro52-1, Ro52-2, Ro52-3, Ro52-4 (partly overlapping Ro52-1 and Ro52-2), and Ro52-5 (partly overlapping Ro52-2 and Ro52-3)], and two Ro52 peptides (176-196 aa and 200-239 aa), all expressed in Escherichia coli. Results: In patients with SARDs, fragment prevalence rates were as follows: Ro52-1 = 3 %, Ro52-2 = 97 %, Ro52-3 = 0 %, Ro52-4 = 9 %, Ro52-5 = 28 %, Ro52 175-196-aa peptide = 6 %, and Ro52 200-239-aa peptide = 74 %. All control samples were negative for the full-length Ro52 and for the five fragments tested. Conclusions: The main epitope of the Ro52 antigen was localized on fragment 2 (aa 125-267), and the majority (97 %) of SARD sera had antibodies that target this fragment. As most of the samples were positive for fragment 2 and only some for fragments 4 or 5, which partially overlap fragment 2, it seems that the target epitope is localized in the middle of fragment 2 or in the area between fragments 4 and 5. No antibody against a single epitope or a combination of epitopes was linked to any of the single SARDs

Patients with rheumatoid arthritis have an altered circulatory aggrecan profile

<p>Abstract</p> <p>Background</p> <p>Rheumatoid arthritis (RA) is a chronic auto-immune disease with extensive articular cartilage destruction. Aggrecan depletion, mediated by aggrecanases is one of the first signs of early cartilage erosion. We investigated, whether measurement of aggrecan and fragments thereof in serum, could be used as biomarkers for joint-disease in RA patients and furthermore characterized the fragments found in the circulation.</p> <p>Methods</p> <p>The study consisted of 38 patients, 12 males (62.2 ± 16.0 years) and 26 females (59.8 ± 20.7 years) diagnosed with RA: 41.5 ± 27.5 mm/h erythrocyte sedimentation rate (ESR), 38.4 ± 34.7 mg/ml C-reactive protein (CRP) and 4.8 ± 1.7 disease activity score (DAS) and 108 healthy age-matched controls. Aggrecan levels were measured using two immunoassays, i.e. the ³⁷⁴ARGSVI-G2 sandwich ELISA measuring aggrecanase-mediated aggrecan degradation and the G1/G2 sandwich assay, detecting aggrecan molecules containing G1 and/or G2 (total aggrecan) We further characterized serum samples by western blots, by using monoclonal antibodies F-78, binding to G1 and G2, or by BC-3, detecting the aggrecanase-generated N-terminal ³⁷⁴ARGSVI neo-epitope.</p> <p>Results</p> <p>Total aggrecan levels in RA patients were significantly decreased from 824.8 ± 31 ng/ml in healthy controls to 570.5 ± 30 ng/ml (31% decrease, P < 0.0001), as measured by the G1/G2 ELISA. Western blot analysis with F-78 showed one strong band at 10 kDa, and weaker bands at 25 and 45 kDa in both healthy controls and RA patients. In contrast, staining for aggrecanase-activity revealed only one strong band in RA patients of 45 kDa.</p> <p>Conclusion</p> <p>This is the first study, which characterizes different aggrecan fragments in human serum. The data strongly suggests that total aggrecan levels, i.e. aggrecan molecules containing G1 and/or G2 are lower in RA patients, and that RA patients have at least one specific subpopulation of aggrecan fragments, namely aggrecanse generated ³⁷⁴ARGSVI fragments. Further clinical studies are needed to investigate the potential of G1/G2 as a structure-related biochemical marker in destructive joint-diseases.</p

Accuracy and standardization of diagnostic methods for the detection of antibodies to citrullinated peptides

Anti-citrullinated peptide antibodies (ACPA) have a very high specificity for rheumatoid arthritis, much more than that of the rheumatoid factor. In addition, ACPA can be found in sera in the pre-clinical phase, are associated with more severe joint destruction and with higher disease activity. In recent years, keeping pace with new knowledge and with progress made in the antigenic composition of tests and in the characterization of immunogenic epitopes, many immunoenzymatic (ELISA) methods of second and third generation have been produced and marketed commercially, and their use has spread among clinical laboratories. Today, completely automated methods are also available, which are easy to use and with a higher throughput, rendering the diagnostic utility of testing ever faster and more effective. This review takes into consideration the more important characteristics of the new ACPA-ELISA tests now commercially available, and also considers recent progress in standardizing test results

Evaluation of BP180 and BP230 ELISA in the diagnosis of mucous membrane pemphigoid limited to the oral cavity: preliminary results

Objectives. Mucous Membrane Pemphigoid (MMP) is the clinical phenotype of a group of rare autoimmune blistering diseases characterized by autoantibodies directed against different structural proteins in epithelial basement membranes. Diagnoses of MMP is routinely verified by direct immunofluorescence (DIF) of oral mucosa biopsy tissue. ELISA detection of autoantibodies in serum is now employed for the diagnosis of pemphigoid and for monitoring the disease activity. The aim of this study was to evaluate ELISA sensitivity, specificity, PPV, NPV in oral MMP patients. Methods. Patients with oral lesions compatible with MMP, were enrolled. Two different specimens were obtained during the surgical biopsy: one for the histopathological assessment and the other for the DIF. ELISA plates, precoated with recombinant ectodomains of the epitope NC16a of the BP180 antigen and carboxy-terminal domains of BP230 antigen were used. All ELISAs were performed according to the manufacturer’s instructions. Values greater than 8,7 U/ml were considered positive. Histopathological and DIF results were considered as the gold standard. Global validation of the test results was established by calculating the sensitivity, specificity and both the positive and negative predictive values. Results. Sixty-four patients were enrolled (M:F=1:4). Ages ranged from 40 to 82 years (mean 61 years). There were 30 patients with MMP, 16 patients with OLP, 14 affected by PV, 3 lichenoid dysplasia and 1 erythema multiforme. ELISA sensitivity and specificity was respectively 47 and 79%. PPV percentage was 67% while NPV was 63%. Conclusions. In suspected oral MPP, both ELISA tests and histopathological + DIF have to be performed because of ELISA low sensitivity. Although BP180 and BP230 are the major target antigens in patients with MMP limited to the oral cavity, they are not the only. This aspect may explain the low sensitivity rate of ELISA in oral MMP when used as the sole diagnostic support

Anti-brain autoantibodies in the serum of schizophrenic patients: a case-control study.

Schizophrenia is considered a neurodevelopmental disorder with a multifactorial pathogenesis where autoimmune factors may play a significant role. The aim of this study was to verify the presence of anti-brain autoantibodies in the serum of schizophrenic patients compared to healthy controls. Autoantibodies against brain were detected by the immunofluorescence method, utilizing sections of rat hippocampus and hypothalamus and of monkey cerebellum. Three different fluorescence patterns were observed, staining the nucleus-cytoplasm of neurons, the neuroendothelial of blood vessel and the neurofilaments. Search for other organ-specific and non organ-specific autoantibodies was performed in all sera by indirect immunofluorescence method, enzyme linked immunosorbent assay and chemiluminescence immunoassay. Results showed a significant association between schizophrenia and anti-brain autoantibodies against the neuroendothelium of blood vessel in hypothalamus, hippocampus and cerebellum; a significant nuclear and cytoplasmic staining of neurons was assessed only for the hippocampus. No other significant association was found, except between schizophrenia and anti-nuclear autoantibodies on HEp-2 cells. In conclusion, these results support the hypothesis of a significant association between schizophrenia and circulating anti-brain autoantibodies, suggesting a diffuse reactivity against the neuroendothelium of blood vessel and highlighting a nuclear and cytoplasmic staining of the neurons of hippocampus

Evaluation of BP180-NC16A ELISA in exclusive oral pemphigoid diagnosis. A comparative study

Objective: Aims of this study were to test the efficacy of anti-BP180-NC160 ELISA in the diagnosis of oral pemphigoid compared to the gold standard, represented by direct immunofluorescence and pathological examination, to correlate the antibody titers with the severity of the disease and the demographical data. Materials and Methods: Patients with a suspect of oral pemphigoid were enrolled and underwent biopsy and sera collection both, in order to perform histopathological examination, direct immunofluorescence and ELISA. The test outcomes were compared, and ELISA sensitivity, specificity, accuracy, and negative and positive predictive values were calculated. Results: ELISA showed good specificity (83.3%), while sensitivity was only 50%. A moderate correlation between antibody titers and disease severity was recorded. Conclusions: Mucomembranous Pemphigoid is an autoimmune autoantibody-mediated blistering disease, often affecting exclusively the oral mucosa. Currently, the biopsy is required to diagnose this disease, but serological tests are also commonly employed during clinical practice as adjunctive tools. BP180-NC160 ELISA should be considered an ancillary diagnostic test in course of oral pemphigoid; direct immunofluorescence&nbsp;+&nbsp;histologic examination remains the diagnostic gold standard