Rheumatoid Arthritis: Pruijn GJ

van Venrooij WJ, Pruijn GJ. · No affiliation provided · Arthritis Res Ther. · Pubmed #18828887 links to  free full text

Abstract: In the previous issue of Arthritis Research & Therapy data are presented showing that circulating immune complexes containing citrullinated fibrin(ogen) are present in anti-citrullinated protein antibody-positive rheumatoid arthritis patients, and that such immune complexes co-localize with complement factor C3 in the rheumatoid synovium. These results corroborate the idea that citrullination is intimately involved in the pathophysiology of rheumatoid arthritis and complete our model (the rheumatoid arthritis cycle) for the development and chronic nature of this disease.

van Venrooij WJ, van Beers JJ, Pruijn GJ. · Department of Biomolecular Chemistry, Radboud University, Nijmegen, The Netherlands. · Ann N Y Acad Sci. · Pubmed #19076355 No free full text.

Abstract: Rheumatoid arthritis (RA) is a common autoimmune disease characterized by chronic inflammation of synovial joints. In most cases this will lead to the formation of pannus tissue, ultimately leading to joint destruction. Early diagnosis, coupled with aggressive use of disease-modifying antirheumatic drugs, has been shown to have a favorable effect on the course of the disease. Therefore, early and accurate diagnosis has become increasingly important. Several sets of criteria have been published to achieve such an early diagnosis, and all of them include measurement of antibodies directed to citrullinated peptides or proteins. This review summarizes our present knowledge about the most well-known and established test to measure these antibodies, the anti-CCP test, which measures antibodies directed to cyclic citrullinated peptides. We describe the current views on how these antibodies are generated and how genetic and environmental parameters are important in this process. The anti-CCP test is more specific than the commonly used RF test (95% versus less than 90%) and has a comparable sensitivity (more than 70%). These antibodies are detectable very early in the disease and are reported to predict the development of erosive RA. Increasing evidence supports a role for these antibodies in the pathology of the disease. In conclusion, testing for anti-CCP autoantibodies is widely accepted as an indispensable tool for diagnosis and early treatment in the management of rheumatoid arthritis patients.

van Venrooij WJ, Zendman AJ, Pruijn GJ. · Department of Biochemistry, Centre for Molecular Life Sciences, Radboud University Nijmegen, Nijmegen, The Netherlands. · Autoimmun Rev. · Pubmed #17110315 No free full text.

Abstract: Rheumatoid arthritis (RA) is a common, systemic autoimmune disease characterized by chronic inflammation of the synovium, that can lead to progressive joint destruction and in many cases results in severe disability and poor quality of life. With the availability of more sophisticated and effective therapies and with increasing evidence that the first few months of disease represent an unique therapeutic opportunity and that such early therapeutic intervention is crucial in preventing irreversible joint damage, it is widely accepted that early and accurate diagnosis of RA is critical in disease management. Within the last three years a growing number of publications have reported that the second generation anti-CCP (cyclic citrullinated peptide) test may become the marker of choice for diagnosing early RA as it appears to be highly specific for the disease with a sensitivity comparable to the widely used but less specific rheumatoid factor test. Additionally, anti-CCP2 positivity can predict future development of RA in both asymptomatic individuals and in patients with undifferentiated arthritis. Furthermore, antibody levels at presentation can correlate with progression to erosive disease.

Zendman AJ, van Venrooij WJ, Pruijn GJ. · Department of Biochemistry, Nijmegen Center for Molecular Life Sciences, Radboud University Nijmegen, The Netherlands. · Rheumatology (Oxford). · Pubmed #16188946 links to  free full text

This publication has no abstract.

Nijenhuis S, Zendman AJ, Vossenaar ER, Pruijn GJ, vanVenrooij WJ. · Department of Biochemistry 161, Radboud University Nijmegen, PO Box 9101, NL-6500 HB Nijmegen, The Netherlands. · Clin Chim Acta. · Pubmed #15530456 No free full text.

Abstract: Rheumatoid arthritis (RA) is a common, systemic autoimmune disease of which the exact etiology is not known. In the past 10 years, substantial progress has been made in the identification of the antigens specifically recognized by the autoantibodies of RA patients. A central factor in this respect is citrullination, a form of post-translational modification that is strongly associated with autoimmunity in RA. Here, we summarize and discuss our current knowledge on (i) autoantibody systems in RA, (ii) the occurrence of peptidylarginine deiminases and (iii) citrullinated proteins in natural and diseased environments, and (iv) genetic factors involved in RA that may influence the generation and presentation of citrullinated proteins and the resulting antibody production against these modified proteins. Citrullination of proteins may play a key role in the initiation and/or the progression of RA. The onset of citrulline-specific autoimmunity in RA is probably mediated by both environmental and genetic factors, and future studies will learn whether therapeutic intervention at the level of citrullination may provide new possibilities to treat RA.

Vossenaar ER, Zendman AJ, van Venrooij WJ, Pruijn GJ. · Department of Biochemistry, University of Nijmegen, Nijmegen, The Netherlands. · Bioessays. · Pubmed #14579251 No free full text.

Abstract: Peptidylarginine deiminase (PAD, EC 3.5.3.15) enzymes catalyze the conversion of protein-bound arginine to citrulline. This post-translational modification may have a big impact on the structure and function of the target protein. In this review, we will discuss the effects of citrullination and its involvement in several human diseases, including rheumatoid arthritis and multiple sclerosis. So far, four isotypes of PAD have been described in mammals. We describe the existence of PAD in non-mammalian vertebrates and the existence of a fifth mammalian PAD. In addition, tissue-specific expression, genomic organization and evolutionary conservation of the different PAD isotypes will be discussed in detail. This article contains supplementary material which may be viewed at the BioEssays website at http://www.interscience.wiley.com/jpages/0265-9247/suppmat/2003/25/v25.1106.html.

van Venrooij WJ, Pruijn GJ. · Department of Biochemistry, University of Nijmegen, Nijmegen, The Netherlands. · Arthritis Res. · Pubmed #11094435 links to  free full text

Abstract: A new autoantibody activity, which is almost 100% specific for rheumatoid arthritis (RA), has been found. The essential part of the B-cell epitope is a modified form of arginine (ie citrulline). The conversion of protein-contained arginine to citrulline is an enzymatic process that is carried out by peptidylarginine deiminase (PAD), an enzyme that appears to be hormonally controlled. Because of its remarkable specificity, citrullination and related processes might open new possibilities for studying the aetiology of RA.

Verpoort KN, Cheung K, Ioan-Facsinay A, van der Helm-van Mil AH, de Vries-Bouwstra JK, Allaart CF, Drijfhout JW, de Vries RR, Breedveld FC, Huizinga TW, Pruijn GJ, Toes RE. · Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands. · Arthritis Rheum. · Pubmed #18050209 links to  free full text

Abstract: OBJECTIVE: In classic studies on the genetic background of antibody production, the major histocompatibility complex (MHC) has been shown to act as the most prominent immune response gene that controls the magnitude and the specificity of antibody production. The strongest genetic risk factor for rheumatoid arthritis (RA), the human MHC HLA-DRB1 shared epitope (SE) alleles, predisposes for antibodies against citrullinated proteins (ACPAs). ACPA levels are higher in SE-positive patients with RA than in SE-negative patients with RA. The aim of the present study was to determine whether SE influences not only the magnitude but also the specificity of the ACPA response. METHODS: In 2 cohorts of anti-citrullinated peptide 2-positive patients with RA, one from a study of recent-onset arthritis (n = 206) and the other from a treatment strategy study (n = 141), serum antibodies against a citrullinated peptide derived from vimentin (cVim) and antibodies against a citrullinated fibrinogen peptide (cFibr) were determined by enzyme-linked immunosorbent assay. HLA-DRB1 genotyping was performed. RESULTS: In the first cohort, SE alleles were significantly associated with the presence of antibodies against cVim (odds ratio [OR] 4.95, 95% confidence interval [95% CI] 1.87-15.3) and were not significantly associated with the presence of antibodies against cFibr (OR 1.71, 95% CI 0.70-4.14). These results were replicated in the second cohort (OR 5.05, 95% CI 1.92-13.6 and OR 1.19, 95% CI 0.30-3.97, respectively). CONCLUSION: In 2 cohorts of ACPA-positive patients with RA, SE alleles predisposed for the development of antibodies against cVim but not for the development of antibodies against cFibr. These data indicate that SE alleles act as "classic" immune response genes in the ACPA response, because they influence both the magnitude and the specificity of this RA-specific antibody response.

Lokate AM, Beusink JB, Besselink GA, Pruijn GJ, Schasfoort RB. · Department of Biomolecular Chemistry, Nijmegen Centre for Molecular Life Sciences, Institute for Molecules and Materials, Radboud University Nijmegen, P. O. Box 9101, NL-6500 HB Nijmegen, The Netherlands. · J Am Chem Soc. · Pubmed #17941638 No free full text.

Abstract: A new commercial surface plasmon resonance (SPR) imaging analysis system with a novel SPR dip angle scanning principle allows the measurement, without the need for labeling, of the exact SPR dip angle. With this system hundreds of biomolecular interactions can be monitored on microarrays simultaneously and with great precision. The potency of this system is demonstrated by automatically monitoring the interactions between citrullinated peptides and serum autoantibodies of 50 rheumatoid arthritis (RA) patients and 29 controls in a single step. The smallest antibody concentration that could be measured in this experimental setup was 0.5 pM.

Zendman AJ, Raijmakers R, Nijenhuis S, Vossenaar ER, Tillaart M, Chirivi RG, Raats JM, van Venrooij WJ, Drijfhout JW, Pruijn GJ. · Department of Biomolecular Chemistry, Nijmegen Center for Molecular Life Sciences, Institute for Molecules and Materials, Radboud University Nijmegen, Nijmegen NL-6500 HB, The Netherlands. · Anal Biochem. · Pubmed #17716614 No free full text.

Abstract: Members of the family of peptidylarginine deiminases (PADs, EC 3.5.3.15) catalyze the posttranslational modification of peptidylarginine into peptidylcitrulline. Citrulline-containing epitopes have been shown to be major and specific targets of autoantibodies produced by rheumatoid arthritis patients. Recently, the citrullination of histone proteins by PAD enzyme was reported to influence gene expression levels. These findings greatly increase the interest in the PAD enzymes and their activities. A few procedures to monitor PAD activity in biological samples have been described previously. However, these assays either have low sensitivity or are rather laborious. Here we describe a reliable and reproducible method for the determination of PAD activity in both purified and crude samples. The method is based on the quantification of PAD-dependent citrullination of peptides, immobilized in microtiter plates, using antibodies that are exclusively reactive with the reaction product(s). Our results demonstrate that this antibody-based assay for PAD activity, called ABAP, is very sensitive and can be applied to monitor PAD activity in biological samples.

Vannini A, Cheung K, Fusconi M, Stammen-Vogelzangs J, Drenth JP, Dall'Aglio AC, Bianchi FB, Bakker-Jonges LE, van Venrooij WJ, Pruijn GJ, Zendman AJ. · Department of Internal Medicine, Cardioangiology, Hepatology, University of Bologna, and Azienda Ospedaliero-Universitaria S. Orsola-Malpighi, Bologna, Italy. · Ann Rheum Dis. · Pubmed #16984940 No free full text.

Abstract: BACKGROUND: Antibodies directed against citrullinated proteins (eg anti-cyclic citrullinated peptide (CCP)) have excellent diagnostic and good prognostic potential for rheumatoid arthritis. Type 1 autoimmune hepatitis (AIH-1) is a chronic liver disease characterised by a variety of serum autoantibodies. Recently, in a large group of patients with AIH-1 without clear rheumatoid arthritis overlap, a relatively high percentage (9%) of anti-CCP2 positivity was scored. OBJECTIVES: To characterise the citrulline-dependence of the observed anti-CCP2 positivity in AIH-1 sera as well as in other groups of patients without rheumatoid arthritis (mainly rheumatic diseases). METHODS: Serum samples of 57 patients with AIH-1 and 66 patients without rheumatoid arthritis, most of them reported as anti-CCP positive, were tested for citrulline-specific reactivity with a second generation anti-CCP kit, with the citrullinated and the corresponding non-citrullinated (arginine-containing) antigen. A subset of AIH-1 sera was also tested with a CCP1 ELISA (and arginine control). RESULTS: The anti-CCP2 reactivity of most non-rheumatoid arthritis rheumatic diseases samples (87-93%) was citrulline-specific, whereas a relatively high percentage of AIH-1 samples (42-50%) turned out to be reactive in a citrulline-independent manner. The use of citrullinated and non-citrullinated CCP1 peptides confirmed a high occurrence of citrulline-independent reactivity in AIH-1 samples. CONCLUSIONS: In rheumatoid arthritis and most non-rheumatoid arthritis rheumatologic disease sera, anti-CCP positivity is citrulline-dependent. However in some patients, particularly patients with AIH-1, citrulline-independent reactivity in the anti-CCP2 test can occur. A positive CCP test in a non-rheumatic disease (eg liver disease) should therefore be interpreted with care, and preferably followed by a control ELISA with a non-citrullinated antigen.

Raats JM, Wijnen EM, Pruijn GJ, van den Hoogen FH, van Venrooij WJ. · Department of Biochemistry, University of Nijmegen, Nijmegen, The Netherlands. · J Rheumatol. · Pubmed #12913924 No free full text.

Abstract: OBJECTIVE: To isolate and characterize monoclonal autoantibodies (Mab) directed to citrullinated antigens from patients with rheumatoid arthritis (RA). METHODS: Using lymphocytes from bone marrow or peripheral blood from RA patients, we constructed antibody fragment libraries representing the antibody repertoire of these individuals. Antibody fragments recognizing a citrulline-containing peptide were selected from these patient libraries. Individual antibody clones were analyzed for germline gene usage and reactivity toward citrullinated (auto)-antigens. RESULTS: Sequence analysis of the cDNA encoding the 21 distinct antibody fragments that were obtained revealed a restricted germline gene usage. Individual antibody clones were positive in both antiperinuclear factor (APF) and antikeratin antibody (AKA) tests, stained citrullinated filaggrin and fibrinogen on Western blots, and reacted with subsets of citrulline-containing peptides in ELISA, but not with noncitrullinated peptides. CONCLUSION: Our report describes the first recombinant human Mab fragments reactive with citrulline-containing peptides. The restricted germline gene usage of these antibodies, and the fact that the VH alleles used are not present in all individuals, may indicate the existence of a genetic predisposition for the development of anticitrulline antibodies in individuals with these germline alleles. The selected antibody clones may facilitate studies on the role of these autoantibodies and their target antigens in the development of RA.

Van Eenennaam H, Vogelzangs JH, Bisschops L, Te Boome LC, Seelig HP, Renz M, De Rooij DJ, Brouwer R, Pluk H, Pruijn GJ, Van Venrooij WJ, Van Den Hoogen FH. · Department of Biochemistry, University of Nijmegen, Nijmegen, the Netherlands. · Clin Exp Immunol. · Pubmed #12452846 links to  free full text

Abstract: Sera from patients suffering from systemic autoimmune diseases such as systemic lupus erythematosus (SLE) and systemic sclerosis (SSc) have been shown to contain reactivities to nuclear components. Autoantibodies specifically targeting nucleolar antigens are found most frequently in patients suffering from SSc or SSc overlap syndromes. We determined the prevalence and clinical significance of autoantibodies directed to nucleolar RNA-protein complexes, the so-called small nucleolar ribonucleoprotein complexes (snoRNPs). A total of 172 patient sera with antinucleolar antibodies were analysed by immunoprecipitation. From 100 of these patients clinical information was obtained by chart review. Autoantibodies directed to snoRNPs were detected not only in patients suffering from SSc and primary Raynaud's phenomenon (RP), but also in patients suffering from SLE, rheumatoid arthritis (RA) and myositis (PM/DM). Antibodies against box C/D small snoRNPs can be subdivided in antifibrillarin positive and antifibrillarin negative reactivity. Antifibrillarin-positive patient sera were associated with a poor prognosis in comparison with antifibrillarin negative (reactivity with U3 or U8 snoRNP only) patient sera. Anti-Th/To autoantibodies were associated with SSc, primary RP and SLE and were found predominantly in patients suffering from decreased co-diffusion and oesophagus motility and xerophthalmia. For the first time autoantibodies that recognize box H/ACA snoRNPs are described, identifying this class of snoRNPs as a novel autoantigenic activity. Taken together, our data show that antinucleolar patient sera directed to small nucleolar ribonucleoprotein complexes are found frequently in other diseases than SSc and that categorization of diagnoses and clinical manifestations based on autoantibody profiles seems particularly informative in patient sera recognizing box C/D snoRNPs.

Robinson WH, DiGennaro C, Hueber W, Haab BB, Kamachi M, Dean EJ, Fournel S, Fong D, Genovese MC, de Vegvar HE, Skriner K, Hirschberg DL, Morris RI, Muller S, Pruijn GJ, van Venrooij WJ, Smolen JS, Brown PO, Steinman L, Utz PJ. · Division of Immunology and Rheumatology, Department of Medicine, Stanford, California, USA. · Nat Med. · Pubmed #11875502 No free full text.

Abstract: We constructed miniaturized autoantigen arrays to perform large-scale multiplex characterization of autoantibody responses directed against structurally diverse autoantigens, using submicroliter quantities of clinical samples. Autoantigen microarrays were produced by attaching hundreds of proteins, peptides and other biomolecules to the surface of derivatized glass slides using a robotic arrayer. Arrays were incubated with patient serum, and spectrally resolvable fluorescent labels were used to detect autoantibody binding to specific autoantigens on the array. We describe and characterize arrays containing the major autoantigens in eight distinct human autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. This represents the first report of application of such technology to multiple human disease sera, and will enable validated detection of antibodies recognizing autoantigens including proteins, peptides, enzyme complexes, ribonucleoprotein complexes, DNA and post-translationally modified antigens. Autoantigen microarrays represent a powerful tool to study the specificity and pathogenesis of autoantibody responses, and to identify and define relevant autoantigens in human autoimmune diseases.