Autoantibodies to argonaute 2 (su antigen)

Like many other classical autoantibodies in systemic rheumatic diseases, anti-Su antibodies were originally defined by the double immunodiffusion assay in the early 80s. However, despite its high prevalence, only a few reports on anti-Su were published in the following years and the progress in characterizing the target antigens and clinical significance was slow, probably due to its inconsistent or poor reactivity in other standard immunoassays. In 2006 the target antigen was identified as the microRNA (miRNA)-binding protein Argonaute 2 (Ago2). Ago2 is a key component of the RNA-induced silencing complex enriched in cytoplasmic foci called GW bodies. Due to preferential reactivity of human autoantibodies with native antigens, immunoprecipitation is the only method to reliably detect anti-Su/Ago2 antibodies. Anti-Su/Ago2 does not appear to have disease specificity since it is found in 10-20% of patients with various rheumatic diseases, including systemic lupus erythematosus, scleroderma, polymyositis/dermatomyositis, and Sjögren's syndrome, as well as apparently healthy individuals at lower prevalence. The clinical significance and the mechanism of production of anti-Su/Ago2 remains to be clarified. Zapotitlán Springer Science+Business Media New York 2013

Autoantibodies to Argonaute 2 (Su antigen)

Like many other classical autoantibodies in systemic rheumatic diseases, anti-Su antibodies were originally defined by the double immunodiffusion assay in the early 80s. However, despite its high prevalence, only a few reports on anti-Su were published in the following years and the progress in characterizing the target antigens and clinical significance was slow, probably due to its inconsistent or poor reactivity in other standard immunoassays. In 2006 the target antigen was identified as the microRNA (miRNA)-binding protein Argonaute 2 (Ago2). Ago2 is a key component of the RNA-induced silencing complex enriched in cytoplasmic foci called GW bodies. Due to preferential reactivity of human autoantibodies with native antigens, immunoprecipitation is the only method to reliably detect anti-Su/Ago2 antibodies. Anti-Su/Ago2 does not appear to have disease specificity since it is found in 10-20% of patients with various rheumatic diseases, including systemic lupus erythematosus, scleroderma, polymyositis/dermatomyositis, and Sj\uf6gren's syndrome, as well as apparently healthy individuals at lower prevalence. The clinical significance and the mechanism of production of anti-Su/Ago2 remains to be clarified

Prevalence and clinical significance of anti-MDA5 antibodies in European patients with polymyositis/dermatomyositis

Objective Polymyositis/dermatomyositis (PM/DM) is an autoimmune disease characterised by skin and muscle inflammation, internal organ involvement and serum disease-specific autoantibodies. The recently identified anti-MDA5 (melanoma differentiation-associated gene 5) antibodies are associated with clinically amyopathic DM (CADM), rapidly progressive interstitial lung disease, severe skin manifestations, and poor prognosis. Our objective was to examine the clinical significance of anti-MDA5 antibodies in a cohort of European Caucasian patients with PM/DM, considering that data on anti-MDA5 serology are limited to Asian and US cohorts. Methods Sera from 76 consecutive adult Italian patients with PM/DM were analysed by immunoprecipitation (IP) of S-35-methionine radiolabelled HeLa and K562 cell extracts, ELISA using recombinant MDA5 protein and IP-Western Blot using rabbit anti-MDA5 antibodies. Clinical associations of anti-MDA5 antibody positive patients were analysed. Results Anti-MDA5 antibodies were identified in 5/76(7%) PM/DM cases and all 5 cases were CADM; anti-MDA5 was the second most common autoantibody in DM after anti-MJ/NXP-2, found in 24% of cases. Compared to 29 anti-MDA5 (-) DM, anti-MDA5 (+) patients have more typical DM skin disease (digit pulp/periungual lesions, Gottron's papules, heliotrope rash) (p=ns). Interstitial lung disease was observed in 315 anti-MDA5 (+) patients but only 14% of anti-MDA5 (-) cases (p=0.048). Conclusion Our study on European patients with PM/DM confirms that anti-MDA5 antibodies are not uncommon. All anti-MDA5 (+) cases are affected by CADM with typical skin disease, while rapidly progressive pulmonary involvement was diagnosed only in one case. Further studies in larger cohorts are necessary to define the clinical significance of anti-MDA5 antibodies in European PM/DM

Autoantibodies to a miRNA-binding protein Argonaute2 (Su antigen) in patients with hepatitis C virus infection

Objectives Chronic liver diseases caused by hepatitis B (HBV) or C virus (HCV) are common worldwide. Despite reports on autoimmunity in viral hepatitis, studies on autoantibodies associated with systemic rheumatic diseases are inconsistent. Testing of a small number of selected autoantibody specificities using ELISA appears to be one reason for inconsistency. Sera from patients with viral hepatitis were tested by immunoprecipitation that will allow unbiased screening of autoantibodies found in systemic rheumatic diseases. Methods Ninety Mexican patients (37 male, 53 female, 26 HBV, 6 HBV+HCV, 58 HCV) with chronic viral hepatitis, confirmed by nested or RT-nested-PCR, HBsAg and anti-HCV antibodies, were studied. Autoantibodies were tested by immunofluorescence, immunoprecipitation and ELISA. Specificities were verified using reference sera. Results Antinuclear antibodies were found in 38% HBV, 17% HBV+HCV, and 28% in HCV. Autontibodies to Argonaute (Ago2, Su antigen), a microRNA binding protein that plays a key role in RNA-induced silencing complex (RISC), was found in 5% (4164) of HCV or HBV+HCV coinfected patients but not in HBV (0126). Anti-Ago2/Su was found in 112 of I-IFN-treated case vs. 3162 in cases without 1-IFN. HCVdid not have other lupus autoantibodies whereas 19% (5126) of HBV had anti-UlRNP+Ku, Ro+La, RNA polymerase II, or possible U5snRNPs. Conclusion Lupus autoantibodies were uncommon in HCV except anti-Ago2/Su. HCV and I-IFN have many ways to affect TLR signaling, miRNA and miRNA binding protein Ago2/Su. To understand the mechanism of specific targeting of Ago2 in HCV may provide a clue to understand the mechanism of specific autoantibody production. Zapotitlán 2010 Copyright CLINICAL AND EXPERIMENTAL RHEUMATOLOGY

Implications in the difference of anti-Mi-2 and -p155/140 autoantibody prevalence in two dermatomyositis cohorts from Mexico City and Guadalajara

Introduction: Autoantibodies and clinical manifestations in polymyositis/dermatomyositis (PM/DM) are affected by both genetic and environmental factors. The high prevalence of DM and anti-Mi-2 in Central America is thought to be associated with the high UV index of the area. The prevalences of autoantibodies and the clinical manifestations of PM/DM were evaluated comparing two cohorts in Mexico. Methods: Ninety-five Mexican patients with PM/DM (66 DM, 29 PM; 67 Mexico City, 28 Guadalajara) were studied. Autoantibodies were characterized by immunoprecipitation using 35S-methionine labeled K562 cell extract. Clinical information was obtained from medical records. Results: DM represented 69% of PM/DM and anti-Mi-2 was the most common autoantibody (35%), followed by anti-p155/140 (11%); however, anti-Jo-1 was only 4%. The autoantibody profile in adult-onset DM in Mexico City versus Guadalajara showed striking differences: anti-Mi-2 was 59% versus 12% (P = 0.0012) whereas anti-p155/140 was 9% versus 35% (P = 0.02), respectively. A strong association of anti-Mi-2 with DM was confirmed and when clinical features of anti-Mi-2 (+) DM (n = 30) versus anti-Mi-2 (-) DM (n = 36) were compared, the shawl sign (86% versus 64%, P < 0.05) was more common in the anti-Mi-2 (+) group (P = 0.0001). Levels of creatine phosphokinase (CPK) were higher in those who were anti-Mi-2 (+) but they responded well to therapy. Conclusions: Anti-Mi-2 has a high prevalence in Mexican DM and is associated with the shawl sign and high CPK. The prevalence of anti-Mi-2 and anti-p155/140 was significantly different in Mexico City versus Guadalajara, which have a similar UV index. This suggests roles of factors other than UV in anti-Mi-2 antibody production. © 2013 Petri et al.; licensee BioMed Central Ltd

IL-12 and IL-18 levels in serum and gingival tissue in aggressive and chronic periodontitis

Introduction: Autoantibodies and clinical manifestations in polymyositis/dermatomyositis (PM/DM) are affected by both genetic and environmental factors. The high prevalence of DM and anti-Mi-2 in Central America is thought to be associated with the high UV index of the area. The prevalences of autoantibodies and the clinical manifestations of PM/DM were evaluated comparing two cohorts in Mexico. Methods: Ninety-five Mexican patients with PM/DM (66 DM, 29 PM; 67 Mexico City, 28 Guadalajara) were studied. Autoantibodies were characterized by immunoprecipitation using 35S-methionine labeled K562 cell extract. Clinical information was obtained from medical records. Results: DM represented 69% of PM/DM and anti-Mi-2 was the most common autoantibody (35%), followed by anti-p155/140 (11%); however, anti-Jo-1 was only 4%. The autoantibody profile in adult-onset DM in Mexico City versus Guadalajara showed striking differences: anti-Mi-2 was 59% versus 12% (P = 0.0012) whereas anti-p155/140 was 9% versus 35% (P = 0.02), respectively. A strong association of anti-Mi-2 with DM was confirmed and when clinical features of anti-Mi-2 (+) DM (n = 30) versus anti-Mi-2 (-) DM (n = 36) were compared, the shawl sign (86% versus 64%, P < 0.05) was more common in the anti-Mi-2 (+) group (P = 0.0001). Levels of creatine phosphokinase (CPK) were higher in those who were anti-Mi-2 (+) but they responded well to therapy. Conclusions: Anti-Mi-2 has a high prevalence in Mexican DM and is associated with the shawl sign and high CPK. The prevalence of anti-Mi-2 and anti-p155/140 was significantly different in Mexico City versus Guadalajara, which have a similar UV index. This suggests roles of factors other than UV in anti-Mi-2 antibody production. " 2013 Petri et al.; licensee BioMed Central Ltd.",,,,,,"10.1186/ar4207",,,"http://hdl.handle.net/20.500.12104/42106","http://www.scopus.com/inward/record.url?eid=2-s2.0-84875689792&partnerID=40&md5=774ec2092f47770afe26f28b277b559e",,,,,,"2",,"Arthritis Research and Therapy",,,,"15",,"Scopu