| 1. |
- Hedström, Anna Karin, et al.
(author)
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Complex Relationships of Smoking, HLA-DRB1 Genes, and Serologic Profiles in Patients With Early Rheumatoid Arthritis : Update From a Swedish Population-Based Case-Control Study
- 2019
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In: Arthritis & Rheumatology. - : WILEY. - 2326-5191 .- 2326-5205. ; 71:9, s. 1504-1511
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Journal article (peer-reviewed)abstract
- Objective Smoking is associated with an increased risk of rheumatoid arthritis (RA) in subsets of patients defined according to the presence or absence of anti-citrullinated protein antibodies (ACPAs) and rheumatoid factors (RFs). Moreover, an interaction between smoking and the HLA-DRB1 shared epitope (SE) has been demonstrated to be a risk factor for seropositive RA. The aim of this study was to investigate the interplay between smoking and the HLA-DRB1 SE with regard to risk of RA in different patient subsets based on ACPA and RF status. Methods Incident cases of RA (3,645 cases, 5,883 matched controls) were divided into 4 subgroups based on the presence or absence of RF and anti-cyclic citrullinated peptide 2 (anti-CCP2) antibodies. The influence of smoking on the risk of disease was determined in each RA subgroup, using logistic regression models with calculation of odds ratios and 95% confidence intervals (95% CIs). The potential interaction between smoking and HLA-DRB1 SE genes was evaluated by calculating the attributable proportion due to interaction (AP). Results In the RF+/anti-CCP2+ subset of RA patients, both smoking and the presence of the HLA-DRB1 SE conferred independent disease risks, and there was a strong interaction between the 2 risk factors (AP 0.4, 95% CI 0.3, 0.5). In the RF-/anti-CCP2+ patient subset, the HLA-DRB1 SE conferred an increased risk of RA, whereas the independent influence of smoking was limited. However, there was a significant interaction between the HLA-DRB1 SE and smoking (AP 0.2, 95% CI 0.02, 0.5). In the RF+/anti-CCP2- patient subset, there was an increased risk of disease among smokers, which was only marginally affected by the presence of the HLA-DRB1 SE, and no interaction between the 2 factors was observed (AP 0.002, 95% CI -0.3, 0.3). In the RF-/anti-CCP2- patient subset, neither smoking nor the presence of the HLA-DRB1 SE conferred an increased risk of RA. Conclusion These findings demonstrate different effects of smoking and HLA-DRB1 in the 4 serologically defined RA subsets.
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| 2. |
- Hedström, Anna Karin, et al.
(author)
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Interplay between alcohol, smoking and HLA genes in RA aetiology
- 2019
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In: RMD Open. - : BMJ. - 2056-5933. ; 5:1
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Journal article (peer-reviewed)abstract
- Objectives The relationship between alcohol consumption and risk for rheumatoid arthritis (RA) is incompletely understood. We aimed to determine the influence of alcohol on anticitrullinated protein antibody (ACPA) positive and ACPA-negative RA and investigate potential interactions between alcohol consumption, smoking and the presence of human leucocyte antigen (HLA)-DRB1-shared epitope (SE).Methods A Swedish population-based case-control study with incident cases of RA was used (3353 cases, 2836 matched controls). Subjects with different HLA-DRB1-SE status, smoking and alcohol consumption were compared regarding risk of ACPA-positive and ACPA-negative RA, by calculating OR with 95% CI employing logistic regression. Interaction on the additive scale between alcohol, HLA-DRB1-SE and smoking was estimated by calculating the attributable proportion (AP) due to interaction.Results Compared with non-drinking, low and moderate alcohol consumption was dose dependently associated with a reduced risk of ACPA-positive and ACPA-negative RA. Independent of smoking habits, non-drinking and the presence of HLA-DRB1-SE interacted to increase the risk of ACPA-positive RA. Among HLA-DRB1-SE positive subjects, there was also a significant interaction between non-drinking and smoking with regard to risk for ACPA-positive RA. A three-way interaction was observed between alcohol, smoking and HLA-DRB1-SE with regard to risk for ACPA-positive RA (AP 0.7, 95% CI 0.6 to 0.8) that remained significant when the influence from the two-way interactions was removed (AP 0.4, 95% CI 0.2 to 0.6).Conclusions Our findings emphasize the need to investigate complex interactions between several environmental and genetic factors in order to better understand the etiology of RA. Whereas of great interest in an aetiological perspective, the finding of a protective role of alcohol on risk for RA must, however, be interpreted with caution in a clinical and public health perspective.
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| 3. |
- Hedström, Anna Karin, et al.
(author)
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Relationship between shift work and the onset of rheumatoid arthritis
- 2017
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In: RMD Open. - : BMJ. - 2056-5933. ; 3:2
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Journal article (peer-reviewed)abstract
- Background Environmental factors play a prominent role in rheumatoid arthritis (RA) aetiology. Shift work has previously been associated with increased RA risk in females. The aim of this study was to investigate the potential association, including a dose-response association, between permanent night shift work, rotating shift work and day-oriented shift work and risk of developing anticitrullinated peptide antibodies (ACPA)-positive and ACPA-negative RA.Methods The present report is based on a population-based, case-control study with incident cases of RA (1951 cases and 2225 controls matched by age, gender and residential area). Using logistic regression, occurrence of RA among subjects who have been exposed to different kinds of shift work was compared with that among those who have never been exposed by calculating the OR with a 95% CI.Results Rotating shift work and day-oriented shift work increased the risk of developing ACPA-positive RA (OR 1.3, 95% CI 1.0 to 1.7 and OR 1.3, 95% CI 1.0 to 1.6), but not ACPA-negative RA. Permanent night shift work appeared to be a protective factor both against ACPA-positive RA (OR 0.7, 95% CI 0.6 to 0.9) and ACPA-negative RA (OR 0.8, 95% CI 0.6 to 1.0). For both subsets of RA, significant trends showed a lower risk of developing RA with increasing duration of permanent night shift work (p value for trend 0.002 vs 0.04).Conclusions Sleep restriction as a consequence of shift work is associated with several biological effects among which changes in melatonin production may be involved. The present epidemiological findings of a complex relationship between sleep patterns and different forms of RA may be of importance for increasing the understanding of the pathophysiology of RA.
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| 4. |
- Jiang, Xia, et al.
(author)
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An Immunochip-based interaction study of contrasting interaction effects with smoking in ACPA-positive versus ACPA-negative rheumatoid arthritis
- 2016
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In: Rheumatology. - : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 55:1, s. 149-155
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Journal article (peer-reviewed)abstract
- Objective: 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.Methods: 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.Results: 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.Conclusion: 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.
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| 7. |
- Lindahl, Hannes, et al.
(author)
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IL-22 Binding Protein Promotes the Disease Process in Multiple Sclerosis
- 2019
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In: Journal of Immunology. - : AMER ASSOC IMMUNOLOGISTS. - 0022-1767 .- 1550-6606. ; 203:4, s. 888-898
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Journal article (peer-reviewed)abstract
- Genome-wide association studies have mapped the specific sequence variants that predispose for multiple sclerosis (MS). The pathogenic mechanisms that underlie these associations could be leveraged to develop safer and more effective MS treatments but are still poorly understood. In this article, we study the genetic risk variant rs17066096 and the candidate gene that encodes IL-22 binding protein (IL-22BP), an antagonist molecule of the cytokine IL-22. We show that monocytes from carriers of the risk genotype of rs17066096 express more IL-22BP in vitro and cerebrospinal fluid levels of IL-22BP correlate with MS lesion load on magnetic resonance imaging. We confirm the pathogenicity of IL-22BP in both rat and mouse models of MS and go on to suggest a pathogenic mechanism involving lack of IL-22-mediated inhibition of T cell-derived IFN-gamma expression. Our results demonstrate a pathogenic role of IL-22BP in three species with a potential mechanism of action involving T cell polarization, suggesting a therapeutic potential of IL-22 in the context of MS.
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| 8. |
- Lourdudoss, Cecilia, et al.
(author)
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Dietary Intake of Polyunsaturated Fatty Acids and Pain in Spite of Inflammatory Control Among Methotrexate-Treated Early Rheumatoid Arthritis Patients.
- 2018
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In: Arthritis care & research. - : Wiley. - 2151-464X .- 2151-4658. ; 70:2, s. 205-212
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Journal article (peer-reviewed)abstract
- OBJECTIVE: To investigate potential associations between dietary intake of polyunsaturated fatty acids (FAs) and pain patterns in early rheumatoid arthritis (RA) patients after 3 months of methotrexate (MTX) treatment.METHODS: We included 591 early RA patients with MTX monotherapy from a population-based prospective case-control study, the Epidemiological Investigation of Rheumatoid Arthritis. Dietary data on polyunsaturated FAs (food frequency questionnaires) were linked with data on unacceptable pain (visual analog scale [VAS] >40 mm), noninflammatory/refractory pain (VAS >40 mm and C-reactive protein [CRP] level <10 mg/liter), and inflammatory pain (VAS >40 mm and CRP level >10 mg/liter) after 3 months. Statistical analysis included logistic regression.RESULTS: After 3 months of MTX treatment, 125 patients (21.2%) had unacceptable pain, of which 92 patients had refractory pain, and 33 patients had inflammatory pain. Omega-3 FA intake was inversely associated with unacceptable pain and refractory pain (odds ratio [OR] 0.57 [95% confidence interval (95% CI) 0.35-0.95] and OR 0.47 [95% CI 0.26-0.84], respectively). The omega-6:omega-3 FA ratio, but not omega-6 FA alone, was directly associated with unacceptable pain and refractory pain (OR 1.70 [95% CI 1.03-2.82] and OR 2.33 [95% CI 1.28-4.24], respectively). Furthermore, polyunsaturated FAs were not associated with either inflammatory pain or CRP level and erythrocyte sedimentation rate at followup. Omega-3 FA supplementation was not associated with any pain patterns.CONCLUSION: Omega-3 FA was inversely associated with, and the omega-6:omega-3 FA ratio was directly associated with, unacceptable and refractory pain, but not with inflammatory pain or systemic inflammation. The inverse association between omega-3 FA and refractory pain may have a role in pain suppression in RA.
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| 9. |
- Pikwer, Mitra, et al.
(author)
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Parity influences the severity of ACPA-negative early rheumatoid arthritis : a cohort study based on the Swedish EIRA material
- 2015
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In: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6362 .- 1478-6354. ; 17
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Journal article (peer-reviewed)abstract
- Background: In women with rheumatoid arthritis (RA) it has been observed that during pregnancy a majority of patients experience amelioration, but after delivery a relapse of the disease is common. However, there are few studies, with diverging results, addressing the effect of parity on the severity of RA over time. Our aim was to explore the impact of parity, with stratification for anti-citrullinated protein antibody (ACPA) status as well as for onset during reproductive age or not. Methods: Female RA cases aged 18-70 years were recruited for the Epidemiological Investigation of Rheumatoid Arthritis (EIRA). Information on disease severity (the health assessment questionnaire (HAQ) and the disease activity score 28 (DAS28)) was retrieved from the Swedish Rheumatology Quality Register at inclusion and 3, 6, 12 and 24 months after diagnosis. Mixed models were used to compare mean DAS28 and HAQ scores over time in parous and nulliparous women. Mean differences at individual follow-up visits were compared using analysis of covariance. The odds of having DAS28 or HAQ above the median in parous verus nulliparous women were estimated in logistic regression models. Results: A total of 1237 female cases (mean age 51 years, 65 % ACPA-positive) were included. ACPA-negative parous women, aged 18-44 years, had on average 1.17 units higher DAS28 (p < 0.001) and 0.43 units higher HAQ score (p < 0.001) compared to nulliparous women during the follow-up time, adjusted for age. In this subgroup, the average DAS28 and HAQ scores were significantly higher in parous women at all follow-up time points. Younger parous ACPA-negative women were significantly more likely to have DAS28 and HAQ values above the median compared to nulliparous women at all follow-up visits. No association between parity and severity of ACPA-positive disease was observed. Conclusions: Parity was a predictor of a more severe RA among ACPA-negative younger women, which might indicate that immunomodulatory changes during and after pregnancy affect RA severity, in particular for the ACPA-negative RA phenotype.
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| 10. |
- Rönnelid, Johan, et al.
(author)
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Anticitrullinated protein/peptide antibody multiplexing defines an extended group of ACPA-positive rheumatoid arthritis patients with distinct genetic and environmental determinants.
- 2018
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In: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 77:2, s. 203-211
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Journal article (peer-reviewed)abstract
- INTRODUCTION: The second generation anticycliccitrullinated peptide (anti-CCP2) assay detects the majority but not all anticitrullinated protein/peptide antibodies (ACPA). Anti-CCP2-positive rheumatoid arthritis (RA) is associated with HLA-DRB1* shared epitope (SE) alleles and smoking. Using a multiplex assay to detect multiple specific ACPA, we have investigated the fine specificity of individual ACPA responses and the biological impact of additional ACPA reactivity among anti-CCP2-negative patients.METHODS: We investigated 2825 patients with RA and 551 healthy controls with full data on anti-CCP2, HLA-DRB1* alleles and smoking history concerning reactivity against 16 citrullinated peptides and arginine control peptides with a multiplex array.RESULTS: The prevalence of the 16 ACPA specificities ranged from 9% to 58%. When reactivity to arginine peptides was subtracted, the mean diagnostic sensitivity increased by 3.2% with maintained 98% specificity. Of the anti-CCP2-negative patients, 16% were found to be ACPA positive. All ACPA specificities associated with SE, and all but one with smoking. Correction for arginine reactivity also conveyed a stronger association with SE for 13/16 peptides. Importantly, when all ACPA specificities were analysed together, SE and smoking associated with RA in synergy among ACPA positive, but not among ACPA-negative subjects also in the anti-CCP2-negative subset.CONCLUSIONS: Multiplexing detects an enlarged group of ACPA-positive but anti-CCP2-negative patients with genetic and environmental attributes previously assigned to anti-CCP2-positive patients. The individual correction for arginine peptide reactivity confers both higher diagnostic sensitivity and stronger association to SE than gross ACPA measurement.
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