Lars Klareskog

Karolinska University Hospital, Tukholma, Stockholm, Sweden

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Publications (328)2956.58 Total impact

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    ABSTRACT: The presence of a new autoantibody system, anti-carbamylated protein (anti-CarP) antibodies, has been identified in rheumatoid arthritis (RA). The presence of anti-CarP antibodies was evaluated in samples taken from individuals who subsequently developed RA before and after onset of symptoms and related to previously analysed antibodies against citrullinated peptides (ACPA specificities) and anti-CCP2. A total of 252 individuals, with 423 samples from before onset of symptoms of RA, and 197 population controls were identified as donors to the Medical Biobank of Northern Sweden; 192 of them were also sampled at the time of diagnosis. All samples were analysed for anti-CarP IgG and anti-CCP2 antibodies using ELISAs. Ten different antibody reactivities against citrullinated antigens (ACPA specificities) were analysed using a custom-made microarray based on the ImmunoCAP ISAC system (Phadia). The concentration of anti-CarP antibodies was significantly increased in the pre-symptomatic individuals compared with controls (P <0.001) and also increased significantly after disease onset (P <0.001). The sensitivity for anti-CarP antibodies in the pre-symptomatic individuals was 13.9% (95% CI: 11 to 17.6) and 42.2% (95% CI: 35.4 to 49.3) following development of RA. Anti-CarP antibody positivity was found in 5.1% to 13.3% of individuals negative for anti-CCP2 or ACPA specificities. Presence of anti-CarP antibodies was significantly related to radiological destruction at baseline, at 24 months and also to radiological change (P <0.05, all). The results indicate that anti-CarP antibodies are associated with disease development, even after adjusting for the presence of different ACPA fine specificities, and in anti-CCP2 negative individuals and contribute to the identification of a subset of patients with worse radiological progression of the disease independent of ACPA.
    Arthritis Research & Therapy 12/2015; 17(1). DOI:10.1186/s13075-015-0536-2 · 3.75 Impact Factor
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    ABSTRACT: To investigate the gene-environment interaction between smoking and single nucleotide polymorphisms (SNPs), using Immunochip material, on the risk of developing either of two serologically defined subsets of RA. Interaction between smoking and 133 648 genetic markers from the Immunochip was examined for two RA subsets, defined by the presence or absence of ACPA. A total of 1590 ACPA-positive and 891 ACPA-negative cases were compared with 1856 controls in the Swedish Epidemiological Investigation of RA (EIRA) case-control study. Logistic regression models were used to determine the presence of interaction. The proportion attributable to interaction was calculated for each smoking-SNP pair. Replication was carried out in an independent dataset from northern Sweden. To further validate and extend the results, interaction analysis was also performed using genome-wide association studies data on EIRA individuals. In ACPA-positive RA, 102 SNPs interacted significantly with smoking, after Bonferroni correction. All 102 SNPs were located in the HLA region, mainly within the HLA class II region, 51 of which were replicated. No additional loci outside chromosome 6 were identified in the genome-wide association studies validation. After adjusting for HLA-DRB1 shared epitope, 15 smoking-SNP pairs remained significant for ACPA-positive RA, with 8 of these replicated (loci: BTNL2, HLA-DRA, HLA-DRB5, HLA-DQA1, HLA-DOB and TAP2). For ACPA-negative RA, no smoking-SNP pairs passed the threshold for significance. Our study presents extended gene variation patterns involved in gene-smoking interaction in ACPA-positive, but not ACPA-negative, RA. Notably, variants in HLA-DRB1 and those in additional genes within the MHC class II region, but not in any other gene regions, showed interaction with smoking. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email:
    Rheumatology (Oxford, England) 08/2015; DOI:10.1093/rheumatology/kev285 · 4.44 Impact Factor
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    ABSTRACT: Human leukocyte antigen (HLA) genes confer substantial risk for autoimmune diseases on a log-additive scale. Here we speculated that differences in autoantigen-binding repertoires between a heterozygote's two expressed HLA variants might result in additional non-additive risk effects. We tested the non-additive disease contributions of classical HLA alleles in patients and matched controls for five common autoimmune diseases: rheumatoid arthritis (ncases = 5,337), type 1 diabetes (T1D; ncases = 5,567), psoriasis vulgaris (ncases = 3,089), idiopathic achalasia (ncases = 727) and celiac disease (ncases = 11,115). In four of the five diseases, we observed highly significant, non-additive dominance effects (rheumatoid arthritis, P = 2.5 × 10(-12); T1D, P = 2.4 × 10(-10); psoriasis, P = 5.9 × 10(-6); celiac disease, P = 1.2 × 10(-87)). In three of these diseases, the non-additive dominance effects were explained by interactions between specific classical HLA alleles (rheumatoid arthritis, P = 1.8 × 10(-3); T1D, P = 8.6 × 10(-27); celiac disease, P = 6.0 × 10(-100)). These interactions generally increased disease risk and explained moderate but significant fractions of phenotypic variance (rheumatoid arthritis, 1.4%; T1D, 4.0%; celiac disease, 4.1%) beyond a simple additive model.
    Nature Genetics 08/2015; DOI:10.1038/ng.3379 · 29.65 Impact Factor
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    ABSTRACT: This study aimed to refine the interaction between cigarette smoking and human leukocyte antigen (HLA) polymorphisms in seropositive rheumatoid arthritis (RA), in the context of a recent amino-acid based HLA model for RA susceptibility. We imputed HLA amino acids and classical alleles from case-control Immunochip array data of 3,588 Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA; case/control=1654/1934), 589 Nurses' Health Study (NHS; 229/360) and 2,125 Korean (1390/735) subjects. We examined interaction effects between heavy smoking (>10 pack-years) and genetic risk score (GRS) from RA-associated amino-acid positions (11, 13, 71 and 74 in HLA-DRβ1; 9 in HLA-B; and 9 in HLA-DPβ1) and from HLA-DRβ1 four-amino-acid haplotypes with an attributable proportion due to interaction (AP) using the additive interaction model. Heavy smoking and all investigated HLA amino-acid positions and haplotypes were associated with RA susceptibility in all three populations. In the interaction analysis, we found a significant deviation from the expected additive joint effect between heavy smoking and the HLA-DRβ1 amino-acid haplotype in all three studies (0.416≤AP≤0.796). We further identified the key interacting variants as being located at amino-acid positions 11 and 13 of HLA-DRβ1 but not the other RA-risk amino-acid positions in all populations. At the positions 11 and 13, there were similar patterns between RA-risk effects and interaction effects of residues. Our findings of significant gene-environment interaction effects implicate that a physical interaction between citrullinated auto-antigens produced by smoking and HLA-DR molecules is characterized by the HLA-DRβ1 four-amino-acid haplotype, primarily by the positions 11 and 13. This article is protected by copyright. All rights reserved. © 2015, American College of Rheumatology.
    Arthritis & Rheumatology 06/2015; DOI:10.1002/art.39228 · 7.87 Impact Factor
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    ABSTRACT: We have previously identified endogenously citrullinated peptides derived from fibrinogen in rheumatoid arthritis (RA) synovial tissues. In this study, we have investigated the auto-antigenicity of four of those citrullinated peptides and explored their feasibility to target anti-citrullinated protein/peptide antibodies (ACPA). The autoantigenic potential of the fibrinogen peptides was investigated by screening 927 serum samples from the Epidemiological Investigation of RA (EIRA) cohort on a peptide microarray based on the ImmunoCAP ISAC® system. In order to assay for ACPA blocking, two independent pools of purified ACPA were incubated with the respective targeting peptide prior binding to CCP2 utilizing the CCPlus® ELISA kit. Two peptides derived from the fibrinogen α chain, Arg573Cit (563-583), and Arg591Cit (580-600), referred to as Cit573 and Cit591, and two peptides from the fibrinogen β chain, Arg72Cit (62-81), and Arg74Cit (62-81) (Cit72 and Cit74) displayed 65 %, 15 %, 35 % and 53 % of immune reactivity among CCP2 positive RA sera, respectively. In CCP2 negative RA sera, a positive reactivity was detected in 5 % (Cit573), 6 % (Cit591), 8 % (Cit72) and 4 % (Cit74). In the competition assay, Cit573 and Cit591 peptides reduced ACPA binding to CCP2 with a maximum of 84 % and 63 % respectively. An additive effect was observed when these peptides were combined. In contrast, Cit74 and Cit72 were less effective. Cyclization of the peptide structure containing Cit573 significantly increased the blocking efficiency. Here we demonstrate extensive autoantibody reactivity against in vivo citrullinated fibrinogen epitopes, and further show the potential use of these peptides for antagonizing ACPA.
    Arthritis research & therapy 06/2015; 17(1):155. DOI:10.1186/s13075-015-0666-6 · 3.75 Impact Factor
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    ABSTRACT: It has previously been shown that an increased number of antibodies against citrullinated peptides/proteins (ACPA) predate the onset of rheumatoid arthritis (RA). Over time antibody positivity expands, involving more specific responses when approaching the onset of symptoms. We investigated the impact of human leukocyte antigen-shared epitope (HLA-SE) alleles and smoking on the development of ACPA, as well as in combination with ACPA during the state of quiescent autoimmunity (before the onset of symptoms), on the development of RA. Blood samples donated to the Medical Biobank of Northern Sweden from individuals prior to the onset of symptoms of RA (n = 370) and after onset (n = 203) and from population-based controls (n = 585) were used. Antibodies against 10 citrullinated peptides, fibrinogen (Fibα561-583, α580-600, ß62-81a, ß62-81b, ß36-52), vimentin (Vim2-17, 60-75), filaggrin (CCP-1/Fil307-324), α-enolase (CEP-1/Eno5-21), collagen type II (citC1359-369), and anti-cyclic citrullinated peptide (CCP)2 antibodies were analysed. HLA-SE-positive individuals were more frequently positive for ACPA compared with HLA-SE-negative individuals prior to the onset of symptoms of RA, particularly for antibodies against CEP-1 and Fibß62-81a (72). Smoking was associated with antibodies against Vim2-17 and citC1359-369. HLA-SE and smoking showed increasing association to the presence of the antibodies closer to disease onset. The highest odds ratio (OR) for development of RA was for the combination of HLA-SE alleles and ACPA positivity, especially for antibodies against Fibß62-81b, CCP-1/Fil307-324, and Fibβ36-52. A gene-environment additive interaction between smoking and HLA-SE alleles for the risk of disease development was found, with the highest OR for individuals positive for antibodies against Fibβ36-52, CEP-1, and Fibα580-600. The relationships between antibodies against the different ACPA specificities, HLA-SE, and smoking showed a variable pattern in individuals prior to the onset of RA. The combination of smoking and HLA-SE alleles was significantly associated with the development of some of the antibody specificities closer to onset of symptoms, and these associations remained significant at diagnosis. An additive gene-environment interaction was found for several of the antibodies for the development of RA.
    Arthritis Research & Therapy 05/2015; 17(1). DOI:10.1186/s13075-015-0638-x · 3.75 Impact Factor
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    ABSTRACT: Objectives Smoking and HLA-DRB1/shared epitope alleles (SE) are risk factors for rheumatoid arthritis (RA) with IgG-class anti-citrullinated peptide/protein antibodies. IgA-class antibodies are to a great extent related to mucosal immunity. This study was done to explore interrelations between cigarette smoking, SE and circulating IgA and/or IgG anti-cyclic citrullinated peptide antibodies (anti-CCP) among early-RA patients to indicate whether IgA and IgG ACPAs are regulated by different mechanisms. Methods Patients from two early-RA cohorts, EIRA-1 (n=1663) and TIRA-2 (n=199), were grouped into four anti-CCP subsets (IgG-/IgA-, IgG-/IgA+, IgG+/IgA- and IgG+/IgA+) and compared regarding association to smoking (current and former) and SE. Interaction between smoking and SE was calculated by the attributable proportion due to interaction (assessing deviation from additivity of effects). Results Smoking was overrepresented among IgA anti-CCP positive patients regardless of IgG anti-CCP, but not in patients with IgG anti-CCP alone. SE was overrepresented among IgG anti-CCP positive patients with or without IgA-class anti-CCP, but not in patients with IgA anti-CCP alone. Ever smoking and SE interacted regarding risk of IgG+/IgA+ RA (AP=0.5, 95% CI=0.4-0.6). No significant interaction was observed regarding IgG-/IgA+ or IgG+/IgA- RA. Conclusions Ever smoking is associated with IgA anti-CCP positive RA whereas SE is associated with IgG anti-CCP positive RA. An interaction between ever smoking and SE is limited to RA characterized by both IgG and IgA anti-CCP. These data provide novel evidence that anti-CCP positive RA can be divided into at least three different serologically defined subsets concerning risk factors, and thus possibly also concerning pathogenesis. This article is protected by copyright. All rights reserved. © 2015, American College of Rheumatology.
    Arthritis and Rheumatology 04/2015; DOI:10.1002/art.39170
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    ABSTRACT: Immunglobulin G (IgG) sialylation represents a key checkpoint that determines the engagement of pro- or anti-inflammatory Fcγ receptors (FcγR) and the direction of the immune response. Whether IgG sialylation influences osteoclast differentiation and subsequently bone architecture has not been determined yet, but may represent an important link between immune activation and bone loss. Here we demonstrate that desialylated, but not sialylated, immune complexes enhance osteoclastogenesis in vitro and in vivo. Furthermore, we find that the Fc sialylation state of random IgG and specific IgG autoantibodies determines bone architecture in patients with rheumatoid arthritis. In accordance with these findings, mice treated with the sialic acid precursor N-acetylmannosamine (ManNAc), which results in increased IgG sialylation, are less susceptible to inflammatory bone loss. Taken together, our findings provide a novel mechanism by which immune responses influence the human skeleton and an innovative treatment approach to inhibit immune-mediated bone loss.
    Nature Communications 03/2015; 6:6651. DOI:10.1038/ncomms7651 · 10.74 Impact Factor
  • Lars Klareskog · Anca I Catrina
    Nature Reviews Rheumatology 03/2015; 11(5). DOI:10.1038/nrrheum.2015.38 · 10.25 Impact Factor
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    ABSTRACT: To study the association between postmenopausal hormone therapy (PMH) use and the risk of rheumatoid arthritis (RA) stratifying the cases by the presence/absence of antibodies against citrullinated peptides (ACPA). A subset of the Epidemiological Investigation of RA (EIRA), a population-based case-control study, comprising postmenopausal women aged 50-70 living in Sweden, between 2006 and 2011 was analysed (523 cases and 1057 controls). All participants answered an extensive questionnaire, including questions regarding PMH use and potential confounders (education, smoking, BMI, oral contraceptives, reproductive factors). We calculated odds ratios (OR) of developing ACPA-positive/-negative RA, with 95 % confidence intervals (CI) and adjusted for age, residential area and smoking. Current users of PMH had a decreased risk of ACPA-positive RA compared with never users (OR 0.6, 95 % CI 0.3-0.9). The decreased risk was observed mainly in the age-group 50-59 years (OR 0.3, 95 % CI 0.1-0.8) but not in the age-group 60-70 years (OR 0.8, 95 % CI 0.4-1.4). Among current users of a combined therapy (estrogen plus progestogens) an OR of 0.3 (95 % CI 0.1-0.7) of ACPA-positive RA was observed, while no significant association was found among women who used estrogen only (OR 0.8, 95 % CI 0.5-1.6). No association between PMH use and ACPA-negative RA was found. PMH use might reduce the risk of ACPA-positive RA in post-menopausal women over 50 years of age, but not of ACPA-negative RA. The negative influence of this treatment on the risk of other chronic conditions cannot be overlooked.
    European Journal of Epidemiology 03/2015; 30(5). DOI:10.1007/s10654-015-0004-y · 5.15 Impact Factor
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    ABSTRACT: The Structural Genomics Consortium (SGC) and its clinical, industry and disease-foundation partners are launching open-source preclinical translational medicine studies.
    dressNature Reviews Drug Discovery 03/2015; 14(3):149-50. DOI:10.1038/nrd4565 · 37.23 Impact Factor
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    ABSTRACT: We performed gene-gene interaction analysis, with HLA-DRB1 shared epitope (SE) alleles for 195 SNPs within immunologically important MAP2Ks, MAP3Ks and MAP4Ks gene families, in 2010 rheumatoid arthritis (RA) patients and 2280 healthy controls. We found a significant statistical interaction for rs10468473 with SE in autoantibody-positive RA. Individuals heterozygous for rs10468473 demonstrated higher expression of total MAP2K4 mRNA in blood, compared to A-allele homozygous. We discovered a novel, putatively translated, "cassette exon" RNA splice form of MAP2K4, differentially expressed in peripheral blood mononuclear cells from 88 RA cases and controls. Within the group of RA patients, we observed a correlation of MAP2K4 isoform expression with carried SE alleles, autoantibody, and rheumatoid factor profiles. αTNF-dependent modulation of isoform expression pattern was detected in the Jurkat cell line. Our data suggest a genetic interaction between MAP2K4 and HLA-DRB1, and the importance of rs10468473 and MAP2K4 splice variants in the development of autoantibody-positive RA. Copyright © 2015. Published by Elsevier Inc.
    Clinical Immunology 02/2015; 158(1). DOI:10.1016/j.clim.2015.02.011 · 3.99 Impact Factor
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    ABSTRACT: Do recent infections affect the risk of rheumatoid arthritis (RA)? We used the population-based case-control study EIRA (N=6401) on incident RA and healthy controls, matched for sex, age, calendar period and area of residence. Gastroenteritis, urinary tract infection, genital infection, prostatitis, sinusitis, tonsillitis and pneumonia during the 2 years before inclusion in the study were investigated. Conditional logistic regression was used to calculate OR, adjusting for smoking and socioeconomic status. Infections in the gastrointestinal and urogenital tract before clinical onset were associated with a lowered risk of RA: gastroenteritis (OR=0.71 (95% CI 0.63 to 0.80)), urinary tract infections (OR=0.78 (95% CI 0.68 to 0.90)) and genital infections (OR=0.80 (95% CI 0.64 to 1.00)), while a non-significant association of similar magnitude was observed for the less common prostatitis (OR=0.64 (95% CI 0.38 to 1.08)). In contrast, no associations were observed for sinusitis, tonsillitis or pneumonia. Gastrointestinal and urogenital infections, but not respiratory infections, are associated with a significantly lowered risk of RA. The results indicate that infections in general do not affect the risk for RA, but that certain infections, hypothetically associated with changes in the gut microbiome, could diminish the risk. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    Annals of the Rheumatic Diseases 02/2015; 74(5). DOI:10.1136/annrheumdis-2014-206493 · 10.38 Impact Factor
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    ABSTRACT: Objective Family history of rheumatoid arthritis (RA) is one of the strongest risk factors for developing RA, and information on family history is, therefore, routinely collected in clinical practice. However, as more genetic and environmental risk factors shared by relatives are identified, the importance of family history may diminish. The aim of this study was to determine how much of the familial risk of RA can be explained by established genetic and nongenetic risk factors.Methods History of RA among first-degree relatives of individuals in the Epidemiological Investigation of Rheumatoid Arthritis case-control study was assessed through linkage to the Swedish Multigeneration Register and the Swedish Patient Register. We used logistic regression models to investigate the decrease in familial risk after successive adjustment for combinations of nongenetic risk factors (smoking, alcohol intake, parity, silica exposure, body mass index, fatty fish consumption, and education), and genetic risk factors (shared epitope [SE] and 76 single-nucleotide polymorphisms [SNPs]).ResultsEstablished nongenetic risk factors did not explain familial risk of either seropositive or seronegative RA to any significant degree. Genetic risk factors accounted for a limited proportion of the familial risk of seropositive RA (unadjusted odds ratio [OR] 4.10, SE-adjusted OR 3.72, SNP-adjusted OR 3.46, and SE and SNP-adjusted OR 3.35).Conclusion Established risk factors only provided an explanation for familial risk of RA in minor part, suggesting that many (familial) risk factors remain to be identified, in particular for seronegative RA. Family history of RA therefore remains an important clinical risk factor for RA, the value of which has not yet been superseded by other information. There is thus a need for further etiologic studies of both seropositive and seronegative RA.
    Arthritis & Rheumatology 01/2015; 67(2):352-362. DOI:10.1002/art.38927 · 7.87 Impact Factor
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    ABSTRACT: To determine the relationship between changes in antibody levels towards citrullinated peptides derived from different candidate autoantigens and therapeutic outcome in early rheumatoid arthritis (RA). Baseline and 3-month serum samples from 316 patients with early RA enrolled in the Swedish Farmacotherapy (SWEFOT) trial were analysed for antibodies against cyclic citrullinated peptides (CCP) and citrullinated peptides derived from vimentin (cVim), fibrinogen (cFib) and α-enolase (CEP-1). At 3-month follow-up, methotrexate monotherapy-inadequate responders were randomised to add-on therapy with sulfasalazine and hydroxychloroquine or infliximab. In these patients, anticitrullinated peptide antibodies (ACPA) were also assessed at 12 and 24 months. The proportion of antibody-positive patients and relative changes in antibody levels were compared across ACPA specificities and related to therapeutic response and radiographic progression. During the 2-year follow-up, the proportion of patients testing positive declined significantly regarding antibodies to cVim, cFib and CEP-1, while anti-CCP antibody occurrence remained stable over time. Turning anti-cVim antibody negative was most common, and anti-cVim antibody seroreversion during the first three months associated with significantly less 2-year radiographic progression compared with patients who remained positive. Median antibody levels of all tested ACPAs declined uniformly during initial methotrexate therapy and following response to add-on therapy, with no significant relation to treatment regimen or radiographic progression. The influence of early antirheumatic therapy on ACPA seroreversions was markedly different across specificities, and early disappearance of anti-cVim antibodies associated with better radiological outcome. Thus, these data suggest that the disappearance of particular ACPA reactivities may be beneficial in early RA. WHO database at the Karolinska institute: CT20080004; and NCT00764725. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to
    Annals of the Rheumatic Diseases 12/2014; DOI:10.1136/annrheumdis-2014-205698 · 10.38 Impact Factor
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    ABSTRACT: Objectives Our objective was to estimate the risk of developing rheumatoid arthritis (RA) associated with a family history of non-RA arthritis-related diseases. This familial co-aggregation is of clinical interest since it is often encountered when assessing family history of RA specifically, but also informative on the genetic overlap between these diseases. Since anticitrullinated peptide antibodies/rheumatoid factor (RF)-positive and RF-negative RA have both specific and shared genetic factors, the familial co-aggregation was assessed separately for seropositive and seronegative disease.Methods Nested case-control study in prospectively recorded Swedish total population data. The Multi-Generation Register identified first-degree relatives. RA and arthritis-related diseases were ascertained through the nationwide patient register. RA serology was based on International Classification of Diseases tenth revision coded diagnoses, mainly reflecting RF. Familial risks were calculated using conditional logistic regression. Results were replicated using the Swedish rheumatology register.Results Familial co-aggregation was found between RA and every studied arthritis-related disease, but the magnitude varied widely, from juvenile idiopathic arthritis (JIA) (seropositive RA OR=3.98 (3.01 to 5.26); seronegative RA OR=5.70 (3.47 to 9.36)) to osteoarthritis (seropositive RA OR=1.03 (1.00 to 1.06); seronegative RA OR=1.05 (1.00 to 1.09)). The familial co-aggregation pattern of non-RA arthritis-related diseases was overall similar for seropositive and seronegative RA. Among those with family history of RA, relatives’ other arthritis-related diseases conferred little or no additional risk.Conclusions Although family history of several arthritis-related diseases may be useful to predict RA (eg, lupus and JIA), others (eg, osteoarthritis and arthralgia) are less useful. Seropositive and seronegative RA had rather similar familial co-aggregation patterns with arthritis-related diseases, suggesting that the two RA subsets are similar in the genetic factors that overlap with these diseases.
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    ABSTRACT: The Fc-glycan profile of IgG1 anti-citrullinated peptide antibodies (ACPA) in rheumatoid arthritis (RA) patients has recently been reported to be different from non-ACPA IgG1, a phenomenon which likely plays a role in RA pathogenesis. Herein we investigate the Fc-glycosylation pattern of all ACPA-IgG isotypes and simultaneously investigate in detail the IgG protein-chain sequence repertoire. IgG from serum or plasma (S/P, n = 14) and synovial fluid (SF, n = 4) from 18 ACPA-positive RA-patients was enriched using Protein G columns followed by ACPA-purification on cyclic citrullinated peptide-2 (CCP2)-coupled columns. Paired ACPA (anti-CCP2 eluted IgG) and IgG flow through (FT) fractions were analyzed by LC-MS/MS-proteomics. IgG peptides, isotypes and corresponding Fc-glycopeptides were quantified and interrogated using uni- and multivariate statistics. The Fc-glycans from the IgG4 peptide EEQFNSTYR was validated using protein A column purification. Relative to FT-IgG4, the ACPA-IgG4 Fc-glycan-profile contained lower amounts (p = 0.002) of the agalacto and asialylated core-fucosylated biantennary form (FA2) and higher content (p = 0.001) of sialylated glycans. Novel differences in the Fc-glycan-profile of ACPA-IgG1 compared to FT-IgG1 were observed in the distribution of bisected forms (n = 5, p = 0.0001, decrease) and mono-antennnary forms (n = 3, p = 0.02, increase). Our study also confirmed higher abundance of FA2 (p = 0.002) and lower abundance of afucosylated forms (n = 4, p = 0.001) in ACPA-IgG1 relative to FT-IgG1 as well as lower content of IgG2 (p = 0.0000001) and elevated content of IgG4 (p = 0.004) in ACPA compared to FT. One λ-variable peptide sequence was significantly increased in ACPA (p = 0.0001). In conclusion, the Fc-glycan profile of both ACPA-IgG1 and ACPA-IgG4 are distinct. Given that IgG1 and IgG4 have different Fc-receptor and complement binding affinities, this phenomenon likely affects ACPA effector- and immune-regulatory functions in an IgG isotype-specific manner. These findings further highlight the importance of antibody characterization in relation to functional in vivo and in vitro studies.
    PLoS ONE 11/2014; 9(11):e113924. DOI:10.1371/journal.pone.0113924 · 3.23 Impact Factor
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    ABSTRACT: A large portion of common variant loci associated with genetic risk for schizophrenia reside within noncoding sequence of unknown function. Here, we demonstrate promoter and enhancer enrichment in schizophrenia variants associated with expression quantitative trait loci (eQTL). The enrichment is greater when functional annotations derived from the human brain are used relative to peripheral tissues. Regulatory trait concordance analysis ranked genes within schizophrenia genome-wide significant loci for a potential functional role, based on colocalization of a risk SNP, eQTL, and regulatory element sequence. We identified potential physical interactions of noncontiguous proximal and distal regulatory elements. This was verified in prefrontal cortex and -induced pluripotent stem cell–derived neurons for the L-type calciumchannel (CACNA1C) risk locus. Our findings point to a functional link between schizophrenia-associated noncoding SNPs and 3D genome architecture associated with chromosomal loopings and transcriptional regulation in the brain.
    Cell Reports 11/2014; 9(4):1-13. DOI:10.1016/j.celrep.2014.10.015 · 8.36 Impact Factor
  • Annals of the Rheumatic Diseases 09/2014; 73(12). DOI:10.1136/annrheumdis-2014-206369 · 10.38 Impact Factor
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    ABSTRACT: Translational medicine is becoming increasingly dependent upon data generated from health care, clinical research, and molecular investigations. This increasing rate of production and diversity in data has brought about several challenges, including the need to integrate fragmented databases, enable secondary use of patient clinical data from health care in clinical research, and to create information systems that clinicians and biomedical researchers can readily use. Our case study effectively integrates requirements from the clinical and biomedical researcher perspectives in a translational medicine setting. Our three principal achievements are (a) a design of a user-friendly web-based system for management and integration of clinical and molecular databases, while adhering to proper de-identification and security measures; (b) providing a real-world test of the system functionalities using clinical cohorts; and (c) system integration with a clinical decision support system to demonstrate system interoperability. We engaged two active clinical cohorts, 747 psoriasis patients and 2001 rheumatoid arthritis patients, to demonstrate efficient query possibilities across the data sources, enable cohort stratification, extract variation in antibody patterns, study biomarker predictors of treatment response in RA patients, and to explore metabolic profiles of psoriasis patients. Finally, we demonstrated system interoperability by enabling integration with an established clinical decision support system in health care. To assure the usefulness and usability of the system, we followed two approaches. First, we created a graphical user interface supporting all user interactions. Secondly we carried out a system performance evaluation study where we measured the average response time in seconds for active users, http errors, and kilobits per second received and sent. The maximum response time was found to be 0.12 seconds; no server or client errors of any kind were detected. In conclusion, the system can readily be used by clinicians and biomedical researchers in a translational medicine setting.
    PLoS ONE 09/2014; 9(9):e104382. DOI:10.1371/journal.pone.0104382 · 3.23 Impact Factor

Publication Stats

20k Citations
2,956.58 Total Impact Points


  • 1996–2015
    • Karolinska University Hospital
      • Department of Rheumatology
      Tukholma, Stockholm, Sweden
  • 1988–2015
    • Karolinska Institutet
      • • Institute of Environmental Medicine - IMM
      • • Center for Molecular Medicine - CMM
      • • Department of Medicine, Huddinge
      • • Department of Neurology
      Сольна, Stockholm, Sweden
  • 2003–2014
    • Harvard Medical School
      Boston, Massachusetts, United States
  • 1975–2013
    • Uppsala University
      • • Department of Medical Sciences
      • • Department of Immunology, Genetics and Pathology
      • • Department of Medical Biochemistry and Microbiology
      Uppsala, Uppsala, Sweden
  • 2012
    • ORGENTEC Diagnostika GmbH
      Mayence, Rheinland-Pfalz, Germany
  • 2009
    • Stockholm County Council
      Tukholma, Stockholm, Sweden
  • 2008
    • Johns Hopkins Medicine
      • Department of Psychiatry and Behavioral Sciences
      Baltimore, Maryland, United States
  • 2006
    • University of California, Davis
      Davis, California, United States
  • 1991–1998
    • Uppsala University Hospital
      • • Department of Surgical Sciences
      • • Department of Pathology
      Uppsala, Uppsala, Sweden
  • 1986
    • Lund University
      Lund, Skåne, Sweden