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G Steiner - One of the best experts on this subject based on the ideXlab platform.

  • p006 anti RA33 hnrnp a2 b1 autoantibodies are associated with the therapeutic response to methotrexate in patients with rheumatoid arthritis
    Annals of the Rheumatic Diseases, 2018
    Co-Authors: Daniela Sieghart, Josef S. Smolen, Paul Studenic, M Grundhuber, S Swiniarski, Alexander Platzer, G Steiner
    Abstract:

    Introduction Besides the determination of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA), anti-RA33 antibodies (which are directed to the nuclear antigen hnRNP-A2) could be of additional diagnostic and/or prognostic value in patients with rheumatoid arthritis (RA) because they are also found in RF/ACPA negative patients.1 Objectives So far, published data on anti-RA33 antibodies refer only to the IgG isotype.2 It was therefore the aim of this study to measure the prevalence of anti-RA33 IgG, IgM and IgA antibodies in patients with RA and to determine their potential prognostic value regarding prediction of response to treatment. Methods To determine the diagnostic sensitivity and specificity of anti-RA33 subtypes sera from 255 RA patients, 258 disease controls and 100 healthy subjects were tested by a prototype anti-RA33 EliA (Thermo Fisher Scientific) for the presence of anti-RA33 IgG, IgA and IgM antibodies. ACPA and RF were routinely measured by EliA and nephelometry, respectively. All RA patients had initially been treated with conventional synthetic drugs (mostly methotrexate, MTX) and were subsequently treated with at least one TNF inhibitor (TNFi). Therapeutic responses to MTX and TNF blocking biologicals were analysed in an inception cohort (n=104) who had started their DMARD therapy at our clinic. To define therapeutic responses the simplified disease activity index (SDAI) and American College of Rheumatology (ACR) responses were calculated. Results Diagnostic specificity was >96% for all 3 anti-RA33 subtypes. Among the 255 RA patients, 11% tested positive for anti-RA33 IgG antibodies, 15% for IgM antibodies and 6% for IgA antibodies. Altogether, 62 patients (24%) had at least one type of anti-RA33 antibody: among these, 24 patients were RF-negative, 26 were ACPA-negative and 18 were RF/ACPA double negative. Thus, in 32 patients (13%), anti-RA33 was the only antibody specificity. Regarding responses to MTX therapy, the percentage of SDAI50 or ACR20 responders, respectively, was significantly higher (p=0.034 for SDAI50 and p=0.005 for ACR20) among anti-RA33 positive patients (with or without RF/ACPA) compared to anti-RA33 negative (but RF/ACPA positive) patients and RF/ACPA negative patients. Thus, 60% of the anti-RA33 positive patients as compared to 37% anti-RA33 negative patients showed a SDAI50 response; similar values were seen for ACR20 responses. Conclusions Apart from their added diagnostic value anti-RA33 antibodies may have also prognostic value for prediction of therapeutic responses to MTX treatment. Therefore anti-RA33 antibodies may be taken into consideration as additional markers that might become helpful tools in therapeutic decision making. References . Nell VPK, Machold KM, Stamm TA, Eberl G, Heinzl H, Uffmann M, Smolen JS, Steiner G. Autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis. Ann Rheum Dis2005;64:1731–6. . Yand X, Wang M, Zhang X, et al. Diagnostic accuracy of anti-RA33 antibody for rheumatoid arthritis: Systematic review and meta-analysis. Clin Exp Rheumatol2016;34(3):539–47. Disclosure of interest D. Sieghart: None declared, P. Studenic: None declared, M. Grundhuber Employee of: Thermo Fisher Scientific-Phadia GmbH, S. Swiniarski Employee of: Thermo Fisher Scientific-Phadia GmbH, A. Platzer: None declared, J. Smolen: None declared, G. Steiner: None declared

  • autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis
    Annals of the Rheumatic Diseases, 2005
    Co-Authors: Valerie Nell, Josef S. Smolen, Klaus P Machold, Tanja Stamm, G Eberl, Harald Heinzl, Martin Uffmann, G Steiner
    Abstract:

    Background: Early treatment prevents progression of joint damage in rheumatoid arthritis (RA), but diagnosis in early disease is impeded by lack of appropriate diagnostic criteria. Objective: To study the value of rheumatoid factor (RF), anti-cyclic citrullinated peptide autoantibodies (anti-CCP), and anti-RA33 autoantibodies for diagnosis of RA and prediction of outcome in patients with very early arthritis. Methods: The prospective follow up inception cohort included 200 patients with very early ( Results: RA was diagnosed in 102 patients, while 98 developed other inflammatory arthropathies. Receiver operator curve analysis showed an optimum cut off level for RF at 50 U/ml, above which anti-CCP and anti-RA33 had no additional diagnostic value. Remarkably, RF ⩾50 U/ml and anti-CCP showed similar sensitivity and high specificity for RA, but overlapped considerably. Anti-RA33 was less specific and did not correlate with RF or anti-CCP. Among patients with RA, 72% showed at least one of these three autoantibodies, compared with 15% of non-RA patients. RF ⩾50 U/ml and anti-CCP were predictors of erosive disease, whereas anti-RA33 was associated with mild disease. Conclusions: Stepwise autoantibody testing in early inflammatory joint disease, starting with RF, followed by anti-CCP (in patients with RF

  • induction of anti RA33 hnrnp autoantibodies and transient spread to u1 a snrnp complex of spliceosome by idiotypic manipulation with anti RA33 antibody preparation in mice
    Clinical and Experimental Rheumatology, 2002
    Co-Authors: G Steiner, Karl Skriner, Ora Shovman, Boris Gilburd, Pnina Langevitz, M Miholits, R Hoet, Y Levy, Gisele Zandmangoddard, Elisabeth Hoefler
    Abstract:

    Objective Anti-RA33 antibodies occur in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) and target the A2/B1 protein of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex 4 which forms part of the spliceosome. The aim of the present study was to evaluate the immune response and pathological features induced in mice immunized with anti-RA33 antibodies or patient-derived recombinant single-chain variable fragments (scFv) of anti-RA33 antibodies. Methods In the first set of the experiment, two strains of mice (C57BL/6J and BALB/c) were immunized with IgG preparations obtained from two patients with RA and one normal donor. One of the patients had high titer anti-RA33 antibodies; the other one showed weak borderline reactivity. In the second set of the experiment three groups of C57BL/6J mice were immunized, respectively, with affinity-purified (AP) anti-RA33 antibodies, scFv of anti-RA33 antibodies and normal human IgG. The immunological response induced in immunized mice was studied by immunoblotting and line immunoassay (LIA). The presence of arthritis, serositis or myositis was assessed six-months following initial immunization. Results While anti-RA33 antibodies developed in only two of the mice immunized with different human IgG fractions, anti-RA33 antibodies were clearly detected in 7 sera of 13 mice immunized with AP anti-RA33 antibodies three months after the boost immunization and, moreover, also in 2 sera of 13 mice immunized with scFv of anti-RA33 antibodies. In contrast, mice immunized with normal human IgG did not develop anti-RA33 antibodies. Interestingly, transient autoantibody production against another nuclear autoantigen, U1 snRNP, was observed in 3 C57BL/6J mice immunized with scFv and in 1 mouse immunized with AP autoantibodies. However, these immunological responses were not associated with pathological findings. Conclusions Active immunization of naive mice with AP anti-RA33 antibodies and scFv of anti-RA33 antibodies resulted on the one hand in the production of murine anti-RA33 antibodies and led, on the other hand, to transient "autoantibody spread" to snRNP component of the spliceosome and other nuclear autoantigens. This "autoantibody spread" probably reflected disregulation of the idiotypic anti-idiotypic cascade.

  • fri0086 characterisation of RA33 hnrnp a2 b1 autoreactive t cells in sle patients
    Annals of the Rheumatic Diseases, 2001
    Co-Authors: R Fritsch, Karl Skriner, J S Smolen, Barbara Bohle, J Neumueller, D Eselboeck, B Jahnschmid, G Steiner
    Abstract:

    Background SLE is a systemic autoimmune disease with distinct immunological characteristics including defective T cell functions, especially concerning IL2 production and proliferation. Furthermore, B-cell hyperactivity is observed leading to the formation of several characteristic autoantibodies (ab), among them ab to the heterogenous nuclear ribonucleoprotein A2/B1 (hnRNP/RA33). These antibodies are known to occur in over 20% of SLE patients. Objectives In order to elucidate the role of T cells and their influence in antibody production in SLE, we studied proliferation of PBMC to purified hnRNP-A2/B1 in SLE patients and healthy controls. Methods Stimulation assays with PBMC of 34 SLE patients and 21 healthy controls were performed. We then proceeded to draw RA33-specific T cell clones (TCC) by cultivation and limiting-dilution cloning of T cell lines. Results While the stimulation indices (SI) in the healthy control group ranged from 0.5 to 3.5 (mean SI: 1.5 ± 0.9), the proliferative response of PBMC of the patient group ranged from 0.7 to 17 with a mean SI of 4.8 ± 4.0 (only 6 of 34 patients had an SI Conclusion Our data reveal that more than 80% of SLE-patients have a significant T cell reactivity (SI >2) to the nuclear protein hnRNP-A2/B1 indicating that the antibody response might be T cell driven. Furthermore, almost 60% of TCC derived from SLE patients were CD8+, which supports the importance of these T cells in SLE. Further studies will have to elucidate the pathogenetic implications of these findings.

  • characterization of autoreactive t cells to the autoantigens hnrnp a2 RA33 and filaggrin in patients with rheumatoid arthritis and controls
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Josef Neumuller, G Steiner
    Abstract:

    In an attempt elucidate the role of autoimmune processes in the pathogenesis of rheumatoid arthritis (RA) we investigated the T cell responses to two autoantigens targeted by autoantibodies of patients with RA, (i) the heterogeneous nuclear ribonucleoprotein (hnRNP) A2/RA33 and (ii) filaggrin which is one of the target structures recognized by anti-citrulline antibodies. Stimulation assays were performed with peripheral blood mononuclear cells of 50 RA patients, 20 patients with osteoarthritis and 21 healthy control individuals using recombinant hnRNP-A2/RA33 as well as some fragments thereof and recombinant filaggrin both in unmodified and citrullinated form. Antigen-specific T cell clones (TCC) were obtained by cultivating T cell lines in the presence of antigen and IL-2 followed by limiting-dilution cloning. Proliferative responses to hnRNP-A2/RA33 were seen in 60% of the RA patients with a mean stimulation index (SI) of 3.5 ± 2.8 and were significantly higher than those observed in the control group (mean SI=1.7 ± 1, P < 0.00005). There was no correlation with the presence of anti-A2/RA33 autoantibodies nor with MHC genes, although more than 60% of the responsive patients carried the shared epitope. Results obtained with recombinant fragments indicated a major T cell epitope to be located in the N-terminal first RNA binding domain of the protein. Anti-A2/RA33 specific TCC (n = 16) derived from RA patients were almost exclusively CD4?, whereas only 7 of 12 TCC derived from controls showed this phenotype, and secreted high amounts of IFNg upon antigen stimulation as did all TCC derived from controls. Proliferative responses to filaggrin in either form were seen in only 25% of the RA patients tested and did not differ from those observed in the control group indicating that filaggrin-reactive T cells do presumably not drive the autoantibody response to citrullinated antigens. Taken together, a Th1 type autoimmune response to hnRNP-A2/RA33 was commonly observed in RA patients suggesting this nuclear protein to constitute a major T cell autoantigen which might be fuelling one of the pathological autoimmune reactions that drive the destructive processes effective in RA.

Josef S. Smolen - One of the best experts on this subject based on the ideXlab platform.

  • p006 anti RA33 hnrnp a2 b1 autoantibodies are associated with the therapeutic response to methotrexate in patients with rheumatoid arthritis
    Annals of the Rheumatic Diseases, 2018
    Co-Authors: Daniela Sieghart, Josef S. Smolen, Paul Studenic, M Grundhuber, S Swiniarski, Alexander Platzer, G Steiner
    Abstract:

    Introduction Besides the determination of rheumatoid factor (RF) and anti-citrullinated protein antibodies (ACPA), anti-RA33 antibodies (which are directed to the nuclear antigen hnRNP-A2) could be of additional diagnostic and/or prognostic value in patients with rheumatoid arthritis (RA) because they are also found in RF/ACPA negative patients.1 Objectives So far, published data on anti-RA33 antibodies refer only to the IgG isotype.2 It was therefore the aim of this study to measure the prevalence of anti-RA33 IgG, IgM and IgA antibodies in patients with RA and to determine their potential prognostic value regarding prediction of response to treatment. Methods To determine the diagnostic sensitivity and specificity of anti-RA33 subtypes sera from 255 RA patients, 258 disease controls and 100 healthy subjects were tested by a prototype anti-RA33 EliA (Thermo Fisher Scientific) for the presence of anti-RA33 IgG, IgA and IgM antibodies. ACPA and RF were routinely measured by EliA and nephelometry, respectively. All RA patients had initially been treated with conventional synthetic drugs (mostly methotrexate, MTX) and were subsequently treated with at least one TNF inhibitor (TNFi). Therapeutic responses to MTX and TNF blocking biologicals were analysed in an inception cohort (n=104) who had started their DMARD therapy at our clinic. To define therapeutic responses the simplified disease activity index (SDAI) and American College of Rheumatology (ACR) responses were calculated. Results Diagnostic specificity was >96% for all 3 anti-RA33 subtypes. Among the 255 RA patients, 11% tested positive for anti-RA33 IgG antibodies, 15% for IgM antibodies and 6% for IgA antibodies. Altogether, 62 patients (24%) had at least one type of anti-RA33 antibody: among these, 24 patients were RF-negative, 26 were ACPA-negative and 18 were RF/ACPA double negative. Thus, in 32 patients (13%), anti-RA33 was the only antibody specificity. Regarding responses to MTX therapy, the percentage of SDAI50 or ACR20 responders, respectively, was significantly higher (p=0.034 for SDAI50 and p=0.005 for ACR20) among anti-RA33 positive patients (with or without RF/ACPA) compared to anti-RA33 negative (but RF/ACPA positive) patients and RF/ACPA negative patients. Thus, 60% of the anti-RA33 positive patients as compared to 37% anti-RA33 negative patients showed a SDAI50 response; similar values were seen for ACR20 responses. Conclusions Apart from their added diagnostic value anti-RA33 antibodies may have also prognostic value for prediction of therapeutic responses to MTX treatment. Therefore anti-RA33 antibodies may be taken into consideration as additional markers that might become helpful tools in therapeutic decision making. References . Nell VPK, Machold KM, Stamm TA, Eberl G, Heinzl H, Uffmann M, Smolen JS, Steiner G. Autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis. Ann Rheum Dis2005;64:1731–6. . Yand X, Wang M, Zhang X, et al. Diagnostic accuracy of anti-RA33 antibody for rheumatoid arthritis: Systematic review and meta-analysis. Clin Exp Rheumatol2016;34(3):539–47. Disclosure of interest D. Sieghart: None declared, P. Studenic: None declared, M. Grundhuber Employee of: Thermo Fisher Scientific-Phadia GmbH, S. Swiniarski Employee of: Thermo Fisher Scientific-Phadia GmbH, A. Platzer: None declared, J. Smolen: None declared, G. Steiner: None declared

  • the rheumatoid arthritis associated autoantigen hnrnp a2 RA33 is a major stimulator of autoimmunity in rats with pristane induced arthritis
    Journal of Immunology, 2007
    Co-Authors: Jonatan Tuncel, Makiyeh Tohidastakrad, Birgit Turk, Serafin Pinolroma, Markus Hoffmann, Karl Skriner, Georg Schett, Guy Serre, Josef S. Smolen
    Abstract:

    A single intradermal injection of the mineral oil pristane in susceptible DA.1F rats induces erosive arthritis closely mimicking rheumatoid arthritis (RA). Pristane-induced arthritis (PIA) is driven by autoreactive T cells but no autoantigen has been identified to date. We therefore analyzed B and T cell responses to autoantigens potentially involved in the pathogenesis of RA, including IgG, citrullinated proteins, stress proteins, glucose-6-phosphate isomerase, and heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 (RA33). IgG and IgM autoantibodies to hnRNP-A2 were detectable in sera of pristane-primed DA.1F rats already 1 wk before disease onset, reached maximum levels during the acute phase, and correlated with arthritis severity. Apart from rheumatoid factor, autoantibodies to other Ags were not observed. CD4 + lymph node cells isolated 10 days after pristane injection produced IFN-γ but not IL-4 in response to stimulation with hnRNP-A2, whereas none of the other candidate Ags elicited cytokine secretion. Surprisingly, hnRNP-A2 also stimulated lymph node cells of naive animals to produce inflammatory cytokines in a MyD88-dependent manner. Furthermore, hnRNP-A2 was highly overexpressed in the joints of rats injected with pristane. Overexpression coincided with the appearance of anti-RA33 Abs and preceded the onset of clinical symptoms of PIA by several days. Taken together, these data suggest hnRNP-A2 to be among the primary inducers of autoimmunity in PIA. Therefore, this Ag might play a pivotal role in the pathogenesis of PIA and possibly also human RA.

  • anti RA33 antibodies antibodies to the heterogeneous nuclear ribonucleoprotein a2
    Autoantibodies (Second Edition), 2007
    Co-Authors: Gunter Steiner, Josef S. Smolen
    Abstract:

    ABSTRACT Anti-RA33 antibodies (Ab) are directed to the heterogeneous nuclear ribonucleoprotein (hnRNP) A2, an abundant nuclear protein that is involved in processing, transport and translation of mRNA. Although hnRNP-A2 appears to be constitutively expressed in most organs and tissues, aberrant overexpression has been observed in certain cancers and in inflamed synovial tissue of patients with rheumatoid arthritis (RA). Anti-RA33 Ab occur in approximately one-third of patients with RA but are rarely detected in other rheumatic diseases, with the exception of systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD) where they are as prevalent as in RA. Since anti-RA33 Ab are already detectable in the earliest stages of RA they are useful diagnostic markers showing a positive predictive value (PPV) for RA of approximately 74%. In the absence of rheumatoid factor (RF) and anti-citrullinated protein Ab (ACPA), anti-RA33 Ab appear to be associated with a relatively favourable prognosis. Similar to RF and ACPA, their role in the pathogenesis of RA is unclear. However, autoreactive T cells directed to hnRNP-A2 appear to be commonly present in blood and synovial fluid of RA patients. Their Th1-like phenotype is suggestive of pathogenic involvement of anti-RA33 autoimmunity.

  • autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis
    Annals of the Rheumatic Diseases, 2005
    Co-Authors: Valerie Nell, Josef S. Smolen, Klaus P Machold, Tanja Stamm, G Eberl, Harald Heinzl, Martin Uffmann, G Steiner
    Abstract:

    Background: Early treatment prevents progression of joint damage in rheumatoid arthritis (RA), but diagnosis in early disease is impeded by lack of appropriate diagnostic criteria. Objective: To study the value of rheumatoid factor (RF), anti-cyclic citrullinated peptide autoantibodies (anti-CCP), and anti-RA33 autoantibodies for diagnosis of RA and prediction of outcome in patients with very early arthritis. Methods: The prospective follow up inception cohort included 200 patients with very early ( Results: RA was diagnosed in 102 patients, while 98 developed other inflammatory arthropathies. Receiver operator curve analysis showed an optimum cut off level for RF at 50 U/ml, above which anti-CCP and anti-RA33 had no additional diagnostic value. Remarkably, RF ⩾50 U/ml and anti-CCP showed similar sensitivity and high specificity for RA, but overlapped considerably. Anti-RA33 was less specific and did not correlate with RF or anti-CCP. Among patients with RA, 72% showed at least one of these three autoantibodies, compared with 15% of non-RA patients. RF ⩾50 U/ml and anti-CCP were predictors of erosive disease, whereas anti-RA33 was associated with mild disease. Conclusions: Stepwise autoantibody testing in early inflammatory joint disease, starting with RF, followed by anti-CCP (in patients with RF

  • characterization of autoreactive t cells to the autoantigens hnrnp a2 RA33 and filaggrin in patients with rheumatoid arthritis and controls
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Josef Neumuller, G Steiner
    Abstract:

    In an attempt elucidate the role of autoimmune processes in the pathogenesis of rheumatoid arthritis (RA) we investigated the T cell responses to two autoantigens targeted by autoantibodies of patients with RA, (i) the heterogeneous nuclear ribonucleoprotein (hnRNP) A2/RA33 and (ii) filaggrin which is one of the target structures recognized by anti-citrulline antibodies. Stimulation assays were performed with peripheral blood mononuclear cells of 50 RA patients, 20 patients with osteoarthritis and 21 healthy control individuals using recombinant hnRNP-A2/RA33 as well as some fragments thereof and recombinant filaggrin both in unmodified and citrullinated form. Antigen-specific T cell clones (TCC) were obtained by cultivating T cell lines in the presence of antigen and IL-2 followed by limiting-dilution cloning. Proliferative responses to hnRNP-A2/RA33 were seen in 60% of the RA patients with a mean stimulation index (SI) of 3.5 ± 2.8 and were significantly higher than those observed in the control group (mean SI=1.7 ± 1, P < 0.00005). There was no correlation with the presence of anti-A2/RA33 autoantibodies nor with MHC genes, although more than 60% of the responsive patients carried the shared epitope. Results obtained with recombinant fragments indicated a major T cell epitope to be located in the N-terminal first RNA binding domain of the protein. Anti-A2/RA33 specific TCC (n = 16) derived from RA patients were almost exclusively CD4?, whereas only 7 of 12 TCC derived from controls showed this phenotype, and secreted high amounts of IFNg upon antigen stimulation as did all TCC derived from controls. Proliferative responses to filaggrin in either form were seen in only 25% of the RA patients tested and did not differ from those observed in the control group indicating that filaggrin-reactive T cells do presumably not drive the autoantibody response to citrullinated antigens. Taken together, a Th1 type autoimmune response to hnRNP-A2/RA33 was commonly observed in RA patients suggesting this nuclear protein to constitute a major T cell autoantigen which might be fuelling one of the pathological autoimmune reactions that drive the destructive processes effective in RA.

Karl Skriner - One of the best experts on this subject based on the ideXlab platform.

  • the rheumatoid arthritis associated autoantigen hnrnp a2 RA33 is a major stimulator of autoimmunity in rats with pristane induced arthritis
    Journal of Immunology, 2007
    Co-Authors: Jonatan Tuncel, Makiyeh Tohidastakrad, Birgit Turk, Serafin Pinolroma, Markus Hoffmann, Karl Skriner, Georg Schett, Guy Serre, Josef S. Smolen
    Abstract:

    A single intradermal injection of the mineral oil pristane in susceptible DA.1F rats induces erosive arthritis closely mimicking rheumatoid arthritis (RA). Pristane-induced arthritis (PIA) is driven by autoreactive T cells but no autoantigen has been identified to date. We therefore analyzed B and T cell responses to autoantigens potentially involved in the pathogenesis of RA, including IgG, citrullinated proteins, stress proteins, glucose-6-phosphate isomerase, and heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 (RA33). IgG and IgM autoantibodies to hnRNP-A2 were detectable in sera of pristane-primed DA.1F rats already 1 wk before disease onset, reached maximum levels during the acute phase, and correlated with arthritis severity. Apart from rheumatoid factor, autoantibodies to other Ags were not observed. CD4 + lymph node cells isolated 10 days after pristane injection produced IFN-γ but not IL-4 in response to stimulation with hnRNP-A2, whereas none of the other candidate Ags elicited cytokine secretion. Surprisingly, hnRNP-A2 also stimulated lymph node cells of naive animals to produce inflammatory cytokines in a MyD88-dependent manner. Furthermore, hnRNP-A2 was highly overexpressed in the joints of rats injected with pristane. Overexpression coincided with the appearance of anti-RA33 Abs and preceded the onset of clinical symptoms of PIA by several days. Taken together, these data suggest hnRNP-A2 to be among the primary inducers of autoimmunity in PIA. Therefore, this Ag might play a pivotal role in the pathogenesis of PIA and possibly also human RA.

  • aberrant expression of the autoantigen heterogeneous nuclear ribonucleoprotein a2 RA33 and spontaneous formation of rheumatoid arthritis associated anti RA33 autoantibodies in tnf α transgenic mice
    Journal of Immunology, 2005
    Co-Authors: Silvia Hayer, Makiyeh Tohidastakrad, Serafin Pinolroma, Karl Skriner, Beatrice Jahnschmid, Silva Haralambous, Sylvie Trembleau, Helene Dumortier, Kurt Redlich, Georg Schett
    Abstract:

    Human TNF-α transgenic (hTNFtg) mice develop erosive arthritis closely resembling rheumatoid arthritis (RA). To investigate mechanisms leading to pathological autoimmune reactions in RA, we examined hTNFtg animals for the presence of RA-associated autoantibodies including Abs to citrullinated epitopes (anti-cyclic citrullinated peptide), heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 (anti-RA33), and heat shock proteins (hsp) (anti-hsp). Although IgM anti-hsp Abs were detected in 40% of hTNFtg and control mice, IgG anti-hsp Abs were rarely seen, and anti-cyclic citrullinated peptide Abs were not seen at all. In contrast, >50% of hTNFtg mice showed IgG anti-RA33 autoantibodies, which became detectable shortly after the onset of arthritis. These Abs were predominantly directed to a short epitope, which was identical with an epitope previously described in MRL/ lpr mice. Incidence of anti-RA33 was significantly decreased in mice treated with the osteoclast inhibitor osteoprotegerin and also in c- fos -deficient mice lacking osteoclasts. Pronounced expression of hnRNP-A2 and a smaller splice variant was seen in joints of hTNFtg mice, whereas expression was low in control animals. Although the closely related hnRNP-A1 was also overexpressed, autoantibodies to this protein were infrequently detected. Because expression of hnRNP-A2 in thymus, spleen, brain, and lung was similar in hTNFtg and control mice, aberrant expression appeared to be restricted to the inflamed joint. Finally, immunization of hTNFtg mice with recombinant hnRNP-A2 or a peptide harboring the major B cell epitope aggravated arthritis. These findings suggest that overproduction of TNF-α leads to aberrant expression of hnRNP-A2 in the rheumatoid joint and subsequently to autoimmune reactions, which may enhance the inflammatory and destructive process.

  • characterization of autoreactive t cells to the autoantigens heterogeneous nuclear ribonucleoprotein a2 RA33 and filaggrin in patients with rheumatoid arthritis
    Journal of Immunology, 2002
    Co-Authors: Ruth Fritsch, Makiyeh Tohidastakrad, Karl Skriner, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Silvia Hayer, Josef Neumuller, Serafin Pinolroma
    Abstract:

    The role of autoimmune reactions in the pathogenesis of rheumatoid arthritis (RA) is poorly understood. To address this issue we have investigated the spontaneous T cell response to two well-characterized humoral autoantigens in RA patients and controls: 1) the heterogeneous nuclear ribonucleoprotein A2, i.e., the RA33 Ag (A2/RA33), and 2) filaggrin in unmodified and citrullinated forms. In stimulation assays A2/RA33 induced proliferative responses in PBMC of almost 60% of the RA patients but in only 20% of the controls (patients with osteoarthritis or psoriatic arthritis and healthy individuals), with substantially stronger responses in RA patients ( p p p

  • induction of anti RA33 hnrnp autoantibodies and transient spread to u1 a snrnp complex of spliceosome by idiotypic manipulation with anti RA33 antibody preparation in mice
    Clinical and Experimental Rheumatology, 2002
    Co-Authors: G Steiner, Karl Skriner, Ora Shovman, Boris Gilburd, Pnina Langevitz, M Miholits, R Hoet, Y Levy, Gisele Zandmangoddard, Elisabeth Hoefler
    Abstract:

    Objective Anti-RA33 antibodies occur in patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and mixed connective tissue disease (MCTD) and target the A2/B1 protein of the heterogeneous nuclear ribonucleoprotein (hnRNP) complex 4 which forms part of the spliceosome. The aim of the present study was to evaluate the immune response and pathological features induced in mice immunized with anti-RA33 antibodies or patient-derived recombinant single-chain variable fragments (scFv) of anti-RA33 antibodies. Methods In the first set of the experiment, two strains of mice (C57BL/6J and BALB/c) were immunized with IgG preparations obtained from two patients with RA and one normal donor. One of the patients had high titer anti-RA33 antibodies; the other one showed weak borderline reactivity. In the second set of the experiment three groups of C57BL/6J mice were immunized, respectively, with affinity-purified (AP) anti-RA33 antibodies, scFv of anti-RA33 antibodies and normal human IgG. The immunological response induced in immunized mice was studied by immunoblotting and line immunoassay (LIA). The presence of arthritis, serositis or myositis was assessed six-months following initial immunization. Results While anti-RA33 antibodies developed in only two of the mice immunized with different human IgG fractions, anti-RA33 antibodies were clearly detected in 7 sera of 13 mice immunized with AP anti-RA33 antibodies three months after the boost immunization and, moreover, also in 2 sera of 13 mice immunized with scFv of anti-RA33 antibodies. In contrast, mice immunized with normal human IgG did not develop anti-RA33 antibodies. Interestingly, transient autoantibody production against another nuclear autoantigen, U1 snRNP, was observed in 3 C57BL/6J mice immunized with scFv and in 1 mouse immunized with AP autoantibodies. However, these immunological responses were not associated with pathological findings. Conclusions Active immunization of naive mice with AP anti-RA33 antibodies and scFv of anti-RA33 antibodies resulted on the one hand in the production of murine anti-RA33 antibodies and led, on the other hand, to transient "autoantibody spread" to snRNP component of the spliceosome and other nuclear autoantigens. This "autoantibody spread" probably reflected disregulation of the idiotypic anti-idiotypic cascade.

  • fri0086 characterisation of RA33 hnrnp a2 b1 autoreactive t cells in sle patients
    Annals of the Rheumatic Diseases, 2001
    Co-Authors: R Fritsch, Karl Skriner, J S Smolen, Barbara Bohle, J Neumueller, D Eselboeck, B Jahnschmid, G Steiner
    Abstract:

    Background SLE is a systemic autoimmune disease with distinct immunological characteristics including defective T cell functions, especially concerning IL2 production and proliferation. Furthermore, B-cell hyperactivity is observed leading to the formation of several characteristic autoantibodies (ab), among them ab to the heterogenous nuclear ribonucleoprotein A2/B1 (hnRNP/RA33). These antibodies are known to occur in over 20% of SLE patients. Objectives In order to elucidate the role of T cells and their influence in antibody production in SLE, we studied proliferation of PBMC to purified hnRNP-A2/B1 in SLE patients and healthy controls. Methods Stimulation assays with PBMC of 34 SLE patients and 21 healthy controls were performed. We then proceeded to draw RA33-specific T cell clones (TCC) by cultivation and limiting-dilution cloning of T cell lines. Results While the stimulation indices (SI) in the healthy control group ranged from 0.5 to 3.5 (mean SI: 1.5 ± 0.9), the proliferative response of PBMC of the patient group ranged from 0.7 to 17 with a mean SI of 4.8 ± 4.0 (only 6 of 34 patients had an SI Conclusion Our data reveal that more than 80% of SLE-patients have a significant T cell reactivity (SI >2) to the nuclear protein hnRNP-A2/B1 indicating that the antibody response might be T cell driven. Furthermore, almost 60% of TCC derived from SLE patients were CD8+, which supports the importance of these T cells in SLE. Further studies will have to elucidate the pathogenetic implications of these findings.

Beatrice Jahnschmid - One of the best experts on this subject based on the ideXlab platform.

  • aberrant expression of the autoantigen heterogeneous nuclear ribonucleoprotein a2 RA33 and spontaneous formation of rheumatoid arthritis associated anti RA33 autoantibodies in tnf α transgenic mice
    Journal of Immunology, 2005
    Co-Authors: Silvia Hayer, Makiyeh Tohidastakrad, Serafin Pinolroma, Karl Skriner, Beatrice Jahnschmid, Silva Haralambous, Sylvie Trembleau, Helene Dumortier, Kurt Redlich, Georg Schett
    Abstract:

    Human TNF-α transgenic (hTNFtg) mice develop erosive arthritis closely resembling rheumatoid arthritis (RA). To investigate mechanisms leading to pathological autoimmune reactions in RA, we examined hTNFtg animals for the presence of RA-associated autoantibodies including Abs to citrullinated epitopes (anti-cyclic citrullinated peptide), heterogeneous nuclear ribonucleoprotein (hnRNP)-A2 (anti-RA33), and heat shock proteins (hsp) (anti-hsp). Although IgM anti-hsp Abs were detected in 40% of hTNFtg and control mice, IgG anti-hsp Abs were rarely seen, and anti-cyclic citrullinated peptide Abs were not seen at all. In contrast, >50% of hTNFtg mice showed IgG anti-RA33 autoantibodies, which became detectable shortly after the onset of arthritis. These Abs were predominantly directed to a short epitope, which was identical with an epitope previously described in MRL/ lpr mice. Incidence of anti-RA33 was significantly decreased in mice treated with the osteoclast inhibitor osteoprotegerin and also in c- fos -deficient mice lacking osteoclasts. Pronounced expression of hnRNP-A2 and a smaller splice variant was seen in joints of hTNFtg mice, whereas expression was low in control animals. Although the closely related hnRNP-A1 was also overexpressed, autoantibodies to this protein were infrequently detected. Because expression of hnRNP-A2 in thymus, spleen, brain, and lung was similar in hTNFtg and control mice, aberrant expression appeared to be restricted to the inflamed joint. Finally, immunization of hTNFtg mice with recombinant hnRNP-A2 or a peptide harboring the major B cell epitope aggravated arthritis. These findings suggest that overproduction of TNF-α leads to aberrant expression of hnRNP-A2 in the rheumatoid joint and subsequently to autoimmune reactions, which may enhance the inflammatory and destructive process.

  • characterization of autoreactive t cells to the autoantigens heterogeneous nuclear ribonucleoprotein a2 RA33 and filaggrin in patients with rheumatoid arthritis
    Journal of Immunology, 2002
    Co-Authors: Ruth Fritsch, Makiyeh Tohidastakrad, Karl Skriner, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Silvia Hayer, Josef Neumuller, Serafin Pinolroma
    Abstract:

    The role of autoimmune reactions in the pathogenesis of rheumatoid arthritis (RA) is poorly understood. To address this issue we have investigated the spontaneous T cell response to two well-characterized humoral autoantigens in RA patients and controls: 1) the heterogeneous nuclear ribonucleoprotein A2, i.e., the RA33 Ag (A2/RA33), and 2) filaggrin in unmodified and citrullinated forms. In stimulation assays A2/RA33 induced proliferative responses in PBMC of almost 60% of the RA patients but in only 20% of the controls (patients with osteoarthritis or psoriatic arthritis and healthy individuals), with substantially stronger responses in RA patients ( p p p

  • characterization of autoreactive t cells to the autoantigens hnrnp a2 RA33 and filaggrin in patients with rheumatoid arthritis and controls
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Josef Neumuller, G Steiner
    Abstract:

    In an attempt elucidate the role of autoimmune processes in the pathogenesis of rheumatoid arthritis (RA) we investigated the T cell responses to two autoantigens targeted by autoantibodies of patients with RA, (i) the heterogeneous nuclear ribonucleoprotein (hnRNP) A2/RA33 and (ii) filaggrin which is one of the target structures recognized by anti-citrulline antibodies. Stimulation assays were performed with peripheral blood mononuclear cells of 50 RA patients, 20 patients with osteoarthritis and 21 healthy control individuals using recombinant hnRNP-A2/RA33 as well as some fragments thereof and recombinant filaggrin both in unmodified and citrullinated form. Antigen-specific T cell clones (TCC) were obtained by cultivating T cell lines in the presence of antigen and IL-2 followed by limiting-dilution cloning. Proliferative responses to hnRNP-A2/RA33 were seen in 60% of the RA patients with a mean stimulation index (SI) of 3.5 ± 2.8 and were significantly higher than those observed in the control group (mean SI=1.7 ± 1, P < 0.00005). There was no correlation with the presence of anti-A2/RA33 autoantibodies nor with MHC genes, although more than 60% of the responsive patients carried the shared epitope. Results obtained with recombinant fragments indicated a major T cell epitope to be located in the N-terminal first RNA binding domain of the protein. Anti-A2/RA33 specific TCC (n = 16) derived from RA patients were almost exclusively CD4?, whereas only 7 of 12 TCC derived from controls showed this phenotype, and secreted high amounts of IFNg upon antigen stimulation as did all TCC derived from controls. Proliferative responses to filaggrin in either form were seen in only 25% of the RA patients tested and did not differ from those observed in the control group indicating that filaggrin-reactive T cells do presumably not drive the autoantibody response to citrullinated antigens. Taken together, a Th1 type autoimmune response to hnRNP-A2/RA33 was commonly observed in RA patients suggesting this nuclear protein to constitute a major T cell autoantigen which might be fuelling one of the pathological autoimmune reactions that drive the destructive processes effective in RA.

  • characterization of RA33 hnrnp a2 b1 autoreactive t cells in sle patients
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Barbara Bohle, J Neumueller, G Steiner
    Abstract:

    SLE is a systemic autoimmune disease with distinct immunological characteristics including defective T cell functions, especially concerning IL2 production and proliferation. Furthermore, B-cell hyperactivity is observed leading to the formation of several characteristic autoantibodies (ab), among them ab to the heterogenous nuclear ribonucleoprotein A2/B1 (hnRNP/RA33). These antibodies are known to occur in over 20% of SLE patients. In order to elucidate the role of T cells and their influence in antibody production in SLE, we studied proliferation of PBMC to purified hnRNP-A2/B1 in 34 SLE patients and 21 healthy controls. While the stimulation indices (SI) in the healthy control group ranged from 0.5 to 3.5 (mean SI: 1.5 ± 0.9), the proliferative response of PBMC of the patient group ranged from 0.7 to 17 with a mean SI of 4.8 ± 4.0 (only 6 of 34 patients had an SI<2; P < 0.00004). We then proceeded to draw RA33-specific T cell clones (TCC) by cultivation and limiting-dilution cloning of T cell lines. The generated 30 TCC derived from SLE patients and 19 TCC from healthy controls did not reveal a significant difference in SI and produced either more IFNγ than IL4 or none of these cytokines at all, suggesting that these TCC were of T1 or T0, but not T2 phenotype. Interestingly though, while only 11% of healthy control patients showed a CD4-/CD8+ subtype and 16% displayed a CD4+/CD8+ phenotype, 37% of TCC derived from SLE patients were CD4-/CD8+ (and 20 % expressed CD4 as well as CD8). Our data reveal that more than 80 % of SLE-patients have a significant T cell reactivity (SI ≥ 2) to the nuclear protein hnRNP-A2/B1 indicating that the antibody response might be T cell driven. Furthermore, almost 60% of TCC derived from SLE patients were CD8+, which supports the importance of these T cells in SLE. Further studies will have to elucidate the pathogenetic implications of these findings.

Ruth Fritsch - One of the best experts on this subject based on the ideXlab platform.

  • characterization of autoreactive t cells to the autoantigens heterogeneous nuclear ribonucleoprotein a2 RA33 and filaggrin in patients with rheumatoid arthritis
    Journal of Immunology, 2002
    Co-Authors: Ruth Fritsch, Makiyeh Tohidastakrad, Karl Skriner, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Silvia Hayer, Josef Neumuller, Serafin Pinolroma
    Abstract:

    The role of autoimmune reactions in the pathogenesis of rheumatoid arthritis (RA) is poorly understood. To address this issue we have investigated the spontaneous T cell response to two well-characterized humoral autoantigens in RA patients and controls: 1) the heterogeneous nuclear ribonucleoprotein A2, i.e., the RA33 Ag (A2/RA33), and 2) filaggrin in unmodified and citrullinated forms. In stimulation assays A2/RA33 induced proliferative responses in PBMC of almost 60% of the RA patients but in only 20% of the controls (patients with osteoarthritis or psoriatic arthritis and healthy individuals), with substantially stronger responses in RA patients ( p p p

  • characterization of autoreactive t cells to the autoantigens hnrnp a2 RA33 and filaggrin in patients with rheumatoid arthritis and controls
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Clemens Scheinecker, Barbara Bohle, Josef Neumuller, G Steiner
    Abstract:

    In an attempt elucidate the role of autoimmune processes in the pathogenesis of rheumatoid arthritis (RA) we investigated the T cell responses to two autoantigens targeted by autoantibodies of patients with RA, (i) the heterogeneous nuclear ribonucleoprotein (hnRNP) A2/RA33 and (ii) filaggrin which is one of the target structures recognized by anti-citrulline antibodies. Stimulation assays were performed with peripheral blood mononuclear cells of 50 RA patients, 20 patients with osteoarthritis and 21 healthy control individuals using recombinant hnRNP-A2/RA33 as well as some fragments thereof and recombinant filaggrin both in unmodified and citrullinated form. Antigen-specific T cell clones (TCC) were obtained by cultivating T cell lines in the presence of antigen and IL-2 followed by limiting-dilution cloning. Proliferative responses to hnRNP-A2/RA33 were seen in 60% of the RA patients with a mean stimulation index (SI) of 3.5 ± 2.8 and were significantly higher than those observed in the control group (mean SI=1.7 ± 1, P < 0.00005). There was no correlation with the presence of anti-A2/RA33 autoantibodies nor with MHC genes, although more than 60% of the responsive patients carried the shared epitope. Results obtained with recombinant fragments indicated a major T cell epitope to be located in the N-terminal first RNA binding domain of the protein. Anti-A2/RA33 specific TCC (n = 16) derived from RA patients were almost exclusively CD4?, whereas only 7 of 12 TCC derived from controls showed this phenotype, and secreted high amounts of IFNg upon antigen stimulation as did all TCC derived from controls. Proliferative responses to filaggrin in either form were seen in only 25% of the RA patients tested and did not differ from those observed in the control group indicating that filaggrin-reactive T cells do presumably not drive the autoantibody response to citrullinated antigens. Taken together, a Th1 type autoimmune response to hnRNP-A2/RA33 was commonly observed in RA patients suggesting this nuclear protein to constitute a major T cell autoantigen which might be fuelling one of the pathological autoimmune reactions that drive the destructive processes effective in RA.

  • characterization of RA33 hnrnp a2 b1 autoreactive t cells in sle patients
    Arthritis Research & Therapy, 2001
    Co-Authors: Ruth Fritsch, Karl Skriner, Josef S. Smolen, Daniela Eselbock, Beatrice Jahnschmid, Barbara Bohle, J Neumueller, G Steiner
    Abstract:

    SLE is a systemic autoimmune disease with distinct immunological characteristics including defective T cell functions, especially concerning IL2 production and proliferation. Furthermore, B-cell hyperactivity is observed leading to the formation of several characteristic autoantibodies (ab), among them ab to the heterogenous nuclear ribonucleoprotein A2/B1 (hnRNP/RA33). These antibodies are known to occur in over 20% of SLE patients. In order to elucidate the role of T cells and their influence in antibody production in SLE, we studied proliferation of PBMC to purified hnRNP-A2/B1 in 34 SLE patients and 21 healthy controls. While the stimulation indices (SI) in the healthy control group ranged from 0.5 to 3.5 (mean SI: 1.5 ± 0.9), the proliferative response of PBMC of the patient group ranged from 0.7 to 17 with a mean SI of 4.8 ± 4.0 (only 6 of 34 patients had an SI<2; P < 0.00004). We then proceeded to draw RA33-specific T cell clones (TCC) by cultivation and limiting-dilution cloning of T cell lines. The generated 30 TCC derived from SLE patients and 19 TCC from healthy controls did not reveal a significant difference in SI and produced either more IFNγ than IL4 or none of these cytokines at all, suggesting that these TCC were of T1 or T0, but not T2 phenotype. Interestingly though, while only 11% of healthy control patients showed a CD4-/CD8+ subtype and 16% displayed a CD4+/CD8+ phenotype, 37% of TCC derived from SLE patients were CD4-/CD8+ (and 20 % expressed CD4 as well as CD8). Our data reveal that more than 80 % of SLE-patients have a significant T cell reactivity (SI ≥ 2) to the nuclear protein hnRNP-A2/B1 indicating that the antibody response might be T cell driven. Furthermore, almost 60% of TCC derived from SLE patients were CD8+, which supports the importance of these T cells in SLE. Further studies will have to elucidate the pathogenetic implications of these findings.