| 1. |
- Lourido, L., et al.
(författare)
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PRESENCE OF FOUR SERUM AUTOANTIBODIES ASSOCIATES WITH THE ACPA STATUS IN EARLY RHEUMATOID ARTHRITIS
- 2021
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ Publishing Group Ltd. - 0003-4967 .- 1468-2060. ; 80, s. 425-426
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The presence of anti-citrullinated protein antibodies (ACPAs) is a hallmark of rheumatoid arthritis (RA) that precede the development of the disease by years and is used for its clinical diagnosis. However, there are RA subjects that test negative for ACPA and thus the early diagnosis on these patients may be delayed. Furthermore, the presence or absence of ACPA in RA supports the hypothesis that on these two subsets of patients underlie different pathogenesis and clinical outcomes.Objectives:In this work, we searched for serum autoantibodies useful to assist the early diagnosis of ACPA-seronegative RA and its management.Methods:We profiled the serum autoantibody repertoire of 80 ACPA-seronegative and 80 ACPA-seropositive RA subjects from the Swedish population-based Epidemiological Investigation of RA (EIRA) cohort. A suspension bead array platform built on protein fragments within Human Protein Atlas and selected from an initial untargeted screening using arrays containing 2660 total antigens was employed to identify IgG and IgA serum autoantibodies. A validation phase on antigen suspension bead arrays was carried out on another set of samples from EIRA containing 386 ACPA-seropositive, 358 ACPA-seronegative and 372 randomly selected control subjects of the same age and sex. A sample-specific threshold based on 20 times the median absolute deviation plus the median of all signals was selected to determine the reactivity of samples. The Wilcoxon rank sum test and Fisher’s test were applied for the comparison of autoantibody levels and reactivity frequencies between the groups.Results:Our data revealed four antigens associated with the ACPA status (Table 1). Testis-specific Y-encoded-like protein 4 (TSPYL4) showed significantly higher IgG reactivity frequency in ACPA-seronegative subjects compared to ACPA-seropositive (8% vs. 3%; P<0.05). Significant differences at IgG autoantibody levels (P<0.05) were also observed between ACPA-seronegative subjects and controls for this specific antigen. Significantly higher IgG autoantibody levels (P<0.05) towards another antigen, dual specificity mitogen-activated protein kinase kinase 6 (MAP2K6), were also observed in ACPA-seronegative subjects compared to ACPA-seropositive and controls. In contrast, we found significantly higher IgG autoantibody levels (P<0.05) in ACPA-seropositive individuals compared to ACPA-seronegative and controls towards two antigens, anosmin-1 (ANOS-1) and muscle related coiled-coil protein (MURC). ANOS-1 shows also significantly higher IgG reactivity frequency in ACPA-seropositive individuals compared to ACPA-seronegative and controls (22%, 9% and 6% respectively; P<0.05). Interestingly, three out of the four antigens discovered to be associated with the ACPA status in early RA are highly expressed in lungs and heart, two of the main extraarticular sites affected in RA. No significant differences were observed at IgA levels for any of the antigens analyzed.Table 1.Scheme of the different phases of the study, the features within each phase and the results. The reactivity to four antigens allows to distinguish ACPA-seronegative (ACPA-), ACPA seropositive (ACPA+) and controls.PhasesUntargeteddiscoveryTargeteddiscoveryTargetedvalidationNumber of samples80 ACPA-80 ACPA-358 ACPA-372 Controls80 ACPA+80 ACPA+386 ACPA+Antigen arrayplatformPlanararraysSuspensionbead array 1Suspensionbead array 2Number of antigens26606227Number of candidatebiomarkers6227 4 (TSPYL4,MAP2K6,ANOS1,MURC)Conclusion:Upon further validation in other early RA sample cohorts, our data suggest the measurement of these four autoantibodies may be useful for the early diagnosis of ACPA-seronegative RA and give insight into the pathogenesis of the different RA subsets.Characters from table content including title and footnotes:Disclosure of Interests:None declared
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| 2. |
- Snir, O., et al.
(författare)
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Multiple antibody reactivities to citrullinated antigens in sera from patients with rheumatoid arthritis : association with HLA-DRB1 alleles
- 2009
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 68:5, s. 736-743
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Tidskriftsartikel (refereegranskat)abstract
- Background: Autoantibodies to cyclic citrullinated peptides (anti-CCP) are present in most patients with rheumatoid arthritis ( RA), and associate with HLA-DRB1 shared epitope (SE) alleles. Objective: To investigate reactivities of anti-CCP to various citrullinated proteins/peptides, which represent potential autoantigens in RA, and to examine the relationship between such antibodies, and their association with genetic variants within HLA-DRB1 SE alleles. Methods: Serum samples from 291 patients with established RA and 100 sex- and age-matched healthy subjects were included in this study. Sera were first analysed for presence of anti-CCP antibodies and further for IgG and IgA antibodies towards candidate autoantigens in both their native and citrullinated form including: fibrinogen, alpha-enolase peptide-1 and the C1-epitope of type II collagen (C1(III)). Antibody specificity was confirmed by cross-reactivity tests. HLA-DR genotyping was performed. Results: 72% of patients with RA were anti-CCP positive. Among the candidate autoantigens examined, IgG antibodies to citrullinated fibrinogen were found in 66% of patients' sera and in 41% for both citrullinated alpha-enolase peptide-1 and citrullinated C1(III). These antibodies were mainly seen in the anti-CCP-positive patient group; they were specific for their respective antigen and displayed limited cross reactivity. IgA responses were also detected, but less frequently than IgG. Anti-CCP and anti-citrullinated protein antibodies were associated with HLA-DRB1*04 rather than with HLA-DRB1*01 alleles. Conclusions: Antibodies directed against several citrullinated antigens are present in CCP-positive RA, with many patients displaying multireactivity. All specific reactivities were primarily associated with the HLA-DRB1*04 alleles, suggesting common pathways of anti-citrulline immunity.
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| 3. |
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| 4. |
- Frodlund, M., et al.
(författare)
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Predictors Of Antibody Response To Covid-19 Vaccine In Rituximab Treated Patients With Inflammatory Rheumatic Diseases. A Swedish Nationwide Study (Covid19-Reuma)
- 2022
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 81, s. 368-369
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- In line with other reports, our group showed that patients treated with rituximab had significant impaired antibody response compared to patients treated with other biologic and targeted and synthetic disease modifying anti-rheumatic drugs (csDMARD).ObjectivesTo investigate predictors of response to COVID-19 vaccination (2 doses of mRNA vaccines, 2 doses of virus vector vaccines or combinations of these) in patients with inflammatory rheumatic diseases (IRD) treated with rituximab and controls.MethodsAntibody levels to three antigens: Spike protein full length, Spike S1 and Nucleocapsid C-terminal fragment (to confirm previous COVID-19 infection) were measured in sera collected before vaccination and 2-12 weeks after the second vaccine using a multiplex bead-based serology assay. The antigen-specific cut-off was defined as the median fluorescence intensity signal plus 6x standard deviations across 12 pre-pandemic controls. A good vaccine response was defined as having antibodies over the cut-off level for both spike antigens. Proportion (%) responders was compared between patients and controls (Chi2 test).Patients with IRD receiving last rituximab treatment within a mean (range) 193 (23-501) days before first vaccination participated. Individuals without IRD served as a control group. Predictors of a good vaccine response were explored using multivariate logistic regression analysis adjusted for age, sex, disease duration, diagnosis (systemic vasculitis/RA/JIA/other), concomitant csDMARD, rituximab dose and prednisolone dose. Hazard ratio (chanse) of a good antibody response in relation to time between the last rituximab treatment and vaccination was studied by Kaplan-Meier survival analysis.ResultsIn total, 145 patients receiving rituximab and 61 controls were inclyded. Of these, 82 received rituximab as monotherapy (67% women; mean age 66 years, mean disease duration 13 years; 33% had RA/JIA and 60% vasculitis) and 63 received rituximab+csDMARD (62% women; mean age 66 years; mean disease duration 17 years; 76% had RA/JIA and 10 % vasculitis). Controls (n=61) were 74% women and mean age 49 years. Compared to controls, rituximab patients had lower antibody levels for both spike proteins (p<0.001). Proportion (%) responders among patients receiving rituximab as monotherapy (40.2%) and rituximab+DMARDs (25.4%) was significantly lower than in controls (98.4%) (p<0.001, Chi2). Higher age, concomitant csDMARD at vaccination and shorter time from last rituximab treatment predicted impaired antibody response (multivariate logistic regression model) (Table 1). Longer time between the last rituximab course and vaccination was associated with better antibody response (Figure 1).Table 1.Predictors of good antibody response to two doses of COVID-19 vaccine defined as antibodies over the cut-off level for both spike antigensBp-valueOR95% CIAge at vaccination (years)-0.040.0090.960.93-0.99Sex (male/female)-9.550.2090.580.24-1.36csDMARD at vaccination (yes/no)-1.080.0260.340.13-0.88Prednisolone (mg/dag)-0.100.1030.900.80-1.02Rituximab dos (1000 mg vs 500 mg)-0.010.3700.990.99-1.00Time between the last rituximab and vaccination (months)0.200.0011.311.11-1.55Diagnosis at vaccination (systemic vasculitis vs others)-0.510.3150.600.21-1.64Figure 1.The chance of good antibody response following two doses of COVID-19 vaccine in relation to time between the last rituximab course and vaccination.ConclusionPatients with IRD getting vaccinated with two doses of COVID19 vaccine during the treatment with rituximab have the ability to develop antibody response although the response is impaired. For each month passed after the last rituximab course, the chance of good antibody response increases with 30%. Younger patients receiving rituximab as monotherapy and vaccinated preferably several months after the last rituximab treatment have the highest chance of achieving a good antibody response.AcknowledgementsUnrestricted research grants have been received from Roche and starting grants from The Swedish Rheumatism AssociationDisclosure of InterestsMartina Frodlund: None declared, Katerina Chatzidionysiou Consultant of: consultancy fees from Eli Lilly, AbbVie and Pfizer., Anna Södergren: None declared, Eva Klingberg: None declared, Monika Hansson: None declared, Elisa Pin: None declared, Sophie Olsson: None declared, Anders Bengtsson: None declared, Lars Klareskog Grant/research support from: has eceived research grants from Pfizer, BMS, Affibody, Sonoma Biotherapeutics, Meliha C Kapetanovic Consultant of: have received consultancy fees from Abbvie, Pfizer and GSK, Grant/research support from: have received unrestricted research grants from Roche and Pfizer
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| 5. |
- Frodlund, M., et al.
(författare)
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The impact of immunomodulating treatment on the serological immunogenicity following three doses of covid-19 vaccine and persistence of immunogenicity of two vaccine doses in patients with inflammatory rheumatic diseases - a swedish study (covid19-reuma)
- 2023
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 82, s. 533-533
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background Data on serological immunity after three doses and the long-term immunogenicity (persistence) of COVID-19 vaccine in patients with inflammatory rheumatic diseases (IRD) treated with different immunomodulating drugs are still limited.Objectives To elucidate if 1) a third dose COVID-19 vaccine improves antibody responses, compared to two doses, in patients with IRD treated with biologic or targeted synthetic DMARD (b/tsDMARDs) treatment given as monotherapy or in combination with conventional synthetic DMARDs (csDMARDs) compared to controls, and 2) the persistence of antibody response after two doses of COVID-19 vaccine in IRD patients.Methods Antibody levels to two antigens representing Spike full length protein and Spike S1 and a Nucleocapsid C-terminal fragment (used to confirm previous COVID-19 infection) were measured in serum samples collected 2-12 and 21-40 weeks after the second vaccine dose and 2-12 weeks after the third dose using a multiplex bead-based serology assay. A sufficient antibody response (seropositivity) was defined as having antibodies over the cut-off level for both spike antigens (1). WT (wild type) anti-Spike IgG and omicron BA.1 and BA.2 variants were measured. Patients with IRD receiving immunomodulating treatment, regularly followed at a rheumatology department and a group of controls were recruited from five Swedish region.Results In total, 323 of 414 patients with IRD and 36 controls who received three vaccine doses participated in this part of the study. Following treatment groups were included: rituximab (n=118; 68% female; mean age 67 years), abatacept (n=18; 72% female; mean age 64 years), IL6r inhibitors (n=60; 73% female; mean age 64 years), JAK-inhibitors (n=44; 80% female, mean age 52 years), TNF-inhibitors (n=59; 70% female; mean age 47 years;), IL12/23/17 inhibitors (n=24; 46% female; mean age 54 years) and controls (n=36; 75% female, mean age 51 years). b/ts DMARD treatment was given as monotherapy or in combination with csDMARD, methotrexate (MTX) being the most frequently used csDMARD (32.5%). Compared to results after two vaccine doses, proportion (%) of seropositivity after three vaccine doses increased significantly in groups rituximab +/- DMARD (p=0.003 and p=0.004, respectively), IL6r inhibitors +DMARD (p=0.02), and abatacept+DMARD (p=0.01). However, the proportion of seropositivity after three vaccine doses was still significantly lower in rituximab treated patients (52%) compared to other treatment groups or controls (p<0.001) (Figure 1A/B). Antibody response to WT, omicron sBA.1 and sBA.2 showed similar pattern with the lowest levels among patients treated with rituximab.When antibody response was compared between 2-12 weeks and 21-40 weeks after second dose, the proportion of seropositive rituximab treated patients decreased from 34.9 % to 32.6%. All patients with JAK inhibitors and with JAK-inhibitors and IL6r-inhibitors seropositive 21-40 weeks after the second vaccine dose. Patients treated with other bDMARDs were not included in this analysis due to limited number participants.Conclusion In this Swedish study including IRD patients receiving different b/t DMARDs, a sufficient immunogenicity of the third dose of COVID-19 vaccine was observed in all treatments with exception for rituximab. However, the increased proportion of seropositivity after the third COVID-19 vaccine doses in rituximab and other patients with insufficient response to two doses including response to the omicron variants, supports the current recommendations on additional booster doses. The immunogenicity of two vaccine doses was preserved to 40 weeks in majority of patients treated with different immunomodulating treatment with exception for rituximab.
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| 6. |
- Ge, Changrong, et al.
(författare)
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Structural Basis of Cross-Reactivity of Anti-Citrullinated Protein Antibodies
- 2019
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Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 71:2, s. 210-221
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Tidskriftsartikel (refereegranskat)abstract
- Objective Anti-citrullinated protein antibodies (ACPAs) develop many years before the clinical onset of rheumatoid arthritis (RA). This study was undertaken to address the molecular basis of the specificity and cross-reactivity of ACPAs from patients with RA. Methods Antibodies isolated from RA patients were expressed as monoclonal chimeric antibodies with mouse Fc. These antibodies were characterized for glycosylation using mass spectrometry, and their cross-reactivity was assessed using Biacore and Luminex immunoassays. The crystal structures of the antigen-binding fragment (Fab) of the monoclonal ACPA E4 in complex with 3 different citrullinated peptides were determined using x-ray crystallography. The prevalence of autoantibodies reactive against 3 of the citrullinated peptides that also interacted with E4 was investigated by Luminex immunoassay in 2 Swedish cohorts of RA patients. Results Analysis of the crystal structures of a monoclonal ACPA from human RA serum in complex with citrullinated peptides revealed key residues of several complementarity-determining regions that recognized the citrulline as well as the neighboring peptide backbone, but with limited contact with the side chains of the peptides. The same citrullinated peptides were recognized by high titers of serum autoantibodies in 2 large cohorts of RA patients. Conclusion These data show, for the first time, how ACPAs derived from human RA serum recognize citrulline. The specific citrulline recognition and backbone-mediated interactions provide a structural explanation for the promiscuous recognition of citrullinated peptides by RA-specific ACPAs.
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| 7. |
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| 8. |
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| 9. |
- Sahlstrom, Peter, et al.
(författare)
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Different Hierarchies of Anti-Modified Protein Autoantibody Reactivities in Rheumatoid Arthritis
- 2020
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Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 72:10, s. 1643-1657
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Anti-citrullinated protein antibodies (ACPAs) are a hallmark of seropositive rheumatoid arthritis (RA). Yet, the precise disease-relevant autoantigens that are targeted by ACPAs remains a matter of debate. This study utilized patient-derived monoclonal ACPAs, rather than serum autoantibody analysis, to characterize the multireactivity to different protein modifications and to reveal autoantibody subsets in patients with RA. Methods. Twelve human monoclonal ACPAs (positive by the second-generation cyclic citrullinated peptide test) were generated from 6 RA patients, and a head-to-head comparison of their reactivities was performed. For profiling, we used a complementary DNA-based protein array (Engine GmbH) and 3 peptide-screening platforms with RA autoantigens (Thermo Fisher Scientific), citrullinated and carbamylated peptides (NimbleGen/Roche), or histonederived peptides with different posttranslational modifications (JPT Histone Code), covering >207,000 peptides (>7,800 gene products). Results. The fine-specificity profiles of the investigated ACPAs varied, but all of the monoclonal ACPAs displayed multireactivity to a large number of citrullinated peptides/proteins, each characterized by specific binding properties. ACPA subsets could be defined by clone-distinct consensus binding motifs (e.g., Cit-Gly, Gly-Cit, or Arg-Cit-Asp), with the most common ACPA recognition being that of a Gly in the +1 flanking position, but with additional amino acid preferences. For ACPA protein recognition, we observed a preference for citrullinated RNA-binding proteins with high Arg/Gly content. Six of the 12 ACPA clones also bound acetylated-lysine (KAc) or homocitrulline peptide motifs, displaying a similar affinity or higher apparent affinity than that for Cit peptides. Conclusion. ACPAs and anti-modified protein autoantibodies represent overlapping facets of RA autoimmunity and bind to a wide variety of modified proteins, extending well beyond the historically recognized set of RA autoantigens. So far, KAc reactivity has been detected only in the context of anti-Carb and anti-Cit peptide autoantibody responses, postulating the existence of hierarchies of autoreactivity in RA. Future investigations of ACPA fine specificities and functionality should take into consideration the presence of consensus Cit/Carb/KAc motifs and the multireactivity of these autoantibodies in patients with RA.
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| 10. |
- Steen, Johanna, et al.
(författare)
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Recognition of Amino Acid Motifs, Rather Than Specific Proteins, by Human Plasma Cell-Derived Monoclonal Antibodies to Posttranslationally Modified Proteins in Rheumatoid Arthritis
- 2019
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Ingår i: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 71:2, s. 196-209
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Antibodies against posttranslationally modified proteins are a hallmark of rheumatoid arthritis (RA), but the emergence and pathogenicity of these autoantibodies are still incompletely understood. The aim of this study was to analyze the antigen specificities and mutation patterns of monoclonal antibodies (mAb) derived from RA synovial plasma cells and address the question of antigen cross-reactivity.Methods: IgG-secreting cells were isolated from RA synovial fluid, and the variable regions of the immunoglobulins were sequenced (n = 182) and expressed in full-length mAb (n = 93) and also as germline-reverted versions. The patterns of reactivity with 53,019 citrullinated peptides and 49,211 carbamylated peptides and the potential of the mAb to promote osteoclastogenesis were investigated.Results: Four unrelated anti-citrullinated protein autoantibodies (ACPAs), of which one was clonally expanded, were identified and found to be highly somatically mutated in the synovial fluid of a patient with RA. The ACPAs recognized >3,000 unique peptides modified by either citrullination or carbamylation. This highly multireactive autoantibody feature was replicated for Ig sequences derived from B cells from the peripheral blood of other RA patients. The plasma cell-derived mAb were found to target distinct amino acid motifs and partially overlapping protein targets. They also conveyed different effector functions as revealed in an osteoclast activation assay.Conclusion: These findings suggest that the high level of cross-reactivity among RA autoreactive B cells is the result of different antigen encounters, possibly at different sites and at different time points. This is consistent with the notion that RA is initiated in one context, such as in the mucosal organs, and thereafter targets other sites, such as the joints.
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