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| 2. |
- Källberg, Henrik, et al.
(författare)
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Gene-gene and gene-environment interactions involving HLA-DRB1, PTPN22, and smoking in two subsets of rheumatoid arthritis
- 2007
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 80:5, s. 867-875
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Tidskriftsartikel (refereegranskat)abstract
- Gene-gene and gene-environment interactions are key features in the development of rheumatoid arthritis (RA) and other complex diseases. The aim of this study was to use and compare three different definitions of interaction between the two major genetic risk factors of RA—the HLA-DRB1 shared epitope (SE) alleles and the PTPN22 R620W allele—in three large case-control studies: the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) study, the North American RA Consortium (NARAC) study, and the Dutch Leiden Early Arthritis Clinic study (in total, 1,977 cases and 2,405 controls). The EIRA study was also used to analyze interactions between smoking and the two genes. “Interaction” was defined either as a departure from additivity, as interaction in a multiplicative model, or in terms of linkage disequilibrium—for example, deviation from independence of penetrance of two unlinked loci. Consistent interaction, defined as departure from additivity, between HLA-DRB1 SE alleles and the A allele of PTPN22 R620W was seen in all three studies regarding anti-CCP–positive RA. Testing for multiplicative interactions demonstrated an interaction between the two genes only when the three studies were pooled. The linkage disequilibrium approach indicated a gene-gene interaction in EIRA and NARAC, as well as in the pooled analysis. No interaction was seen between smoking and PTPN22 R620W. A new pattern of interactions is described between the two major known genetic risk factors and the major environmental risk factor concerning the risk of developing anti-CCP–positive RA. The data extend the basis for a pathogenetic hypothesis for RA involving genetic and environmental factors. The study also raises and illustrates principal questions concerning ways to define interactions in complex diseases.
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| 3. |
- Källberg, Henrik, et al.
(författare)
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Smoking is a major preventable risk factor for rheumatoid arthritis : estimations of risks after various exposures to cigarette smoke
- 2011
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 70:3, s. 508-511
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Tidskriftsartikel (refereegranskat)abstract
- Background Earlier studies have demonstrated that smoking and genetic risk factors interact in providing an increased risk of rheumatoid arthritis (RA). Less is known on how smoking contributes to RA in the context of genetic variability, and what proportion of RA may be caused by smoking. Objectives To determine the association between the amount of smoking and risk of RA in the context of different HLA-DRB1 shared epitope (SE) alleles, and to estimate proportions of RA cases attributed to smoking. Design, Setting and Participants Data from the Swedish Epidemiological Investigation of Rheumatoid Arthritis (EIRA) case-control study encompassing 1204 cases and 871 controls were analysed. Main Outcome Measure Estimated OR to develop RA and excess fraction of cases attributable to smoking according to the amount of smoking and genotype. Results Smoking was estimated to be responsible for 35% of anticitrullinated protein/peptide antibody (ACPA)positive cases. For each HLA-DRB1 SE genotype, smoking was dose-dependently associated with an increased risk of ACPA-positive RA (p trend <0.001). In individuals carrying two copies of the HLA-DRB1 SE, 55% of ACPA-positive RA was attributable to smoking. Conclusions Smoking is a preventable risk factor for RA. The increased risk due to smoking is dependent on the amount of smoking and genotype.
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- Lundberg, Karin, et al.
(författare)
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Genetic and environmental determinants for disease risk in subsets of rheumatoid arthritis defined by the anticitrullinated protein/peptide antibody fine specificity profile
- 2013
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Ingår i: Annals of the Rheumatic Diseases. - Stockholm : Karolinska Institutet, Dept of Medicine, Solna. - 1468-2060 .- 0003-4967.
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To increase understanding of the aetiology and pathogenesis of rheumatoid arthritis (RA), genetic and environmental risk factors for RA subsets, defined by the presence or absence of different anticitrullinated protein/peptide antibodies (ACPAs) targeting citrullinated peptides from α-enolase, vimentin, fibrinogen and collagen type II, were investigated. METHODS: 1985 patients with RA and 2252 matched controls from the EIRA case-control cohort were used in the study. Serum samples were assayed by ELISA for the presence of anticyclic citrullinated peptides (anti-CCP) antibodies and four different ACPA fine specificities. Cross-reactivity between ACPAs was examined by peptide absorption experiments. Genotyping was performed for HLA-DRB1 shared epitope (SE) alleles and the PTPN22 gene, while information regarding smoking was obtained by questionnaire. The association of genetic and environmental risk factors with different subsets of RA was calculated by logistic regression analysis. RESULTS: Limited cross-reactivity was observed between different ACPA fine specificities. In total, 17 RA subsets could be identified based on their different ACPA fine specificity profiles. Large differences in association with genetic and environmental determinants were observed between subsets. The strongest association of HLA-DRB1 SE, PTPN22 and smoking was identified for the RA subset which was defined by the presence of antibodies to citrullinated α-enolase and vimentin. CONCLUSION: This study provides the most comprehensive picture to date of how HLA-DRB1 SE, PTPN22 and smoking are associated with the presence of specific ACPA reactivities rather than anti-CCP levels. The new data will form a basis for molecular studies aimed at understanding disease development in serologically distinct subsets of RA.
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| 5. |
- Lundström, Emeli, et al.
(författare)
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HLA-DRB1*04/*13 alleles are associated with vascular disease and antiphospholipid antibodies in systemic lupus erythematosus
- 2013
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 72:6, s. 1018-1025
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES:Vascular disease is common in systemic lupus erythematosus (SLE) and patients with antiphospholipid antibodies (aPL) are at high risk to develop arterial and venous thrombosis. Since HLA class II genotypes have been linked to the presence of pro-thrombotic aPL, we investigated the relationship between HLA-DRB1 alleles, aPL and vascular events in SLE patients.METHODS:665 SLE patients of Caucasian origin and 1403 controls were included. Previous manifestations of ischaemic heart disease, ischaemic cerebrovascular disease (ICVD) and venous thromboembolism (together referred to as any vascular events (AVE)) were tabulated. aPL were measured with ELISA. Two-digit HLA-DRB1 typing was performed by sequence-specific primer-PCR.RESULTS: HLA-DRB1*04 was more frequent among SLE patients with ICVD compared to unaffected patients. This association remained after adjustment for known traditional cardiovascular risk factors. HLA-DRB1*13 was associated with AVE. All measured specificities of aPL—cardiolipin IgG and IgM, β2-glycoprotein-1 IgG, prothrombin (PT) IgG and a positive lupus anticoagulant test were associated with HLA-DRB1*04—while HLA-DRB1*13 was associated with IgG antibodies (β2-glycoprotein-1, cardiolipin and PT). In patients with the combined risk alleles, HLA-DRB1*04/*13, there was a significant additive interaction for the outcomes AVE and ICVD.CONCLUSIONS:The HLA-DRB1*04 and HLA-DRB1*13 alleles are associated with vascular events and an aPL positive immune-phenotype in SLE. Results demonstrate that a subset of SLE patients is genetically disposed to vascular vulnerability.
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| 6. |
- Lundström, Emeli, et al.
(författare)
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Opposing effects of HLA-DRB1*13 alleles on the risk of developing anti-citrullinated protein antibody-positive and anti-citrullinated protein antibody-negative rheumatoid arthritis
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:4, s. 924-930
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The effect of non-shared epitope HLA-DRB1 alleles on rheumatoid arthritis (RA) is poorly understood. This study was undertaken to investigate the effects of several HLA-DRB1 alleles, independent of the shared epitope, on the risk of developing anti-citrullinated protein antibody (ACPA)-positive or ACPA-negative RA in a large case-control study. METHODS: HLA typing for the DRB1 gene was performed in 1,352 patients with RA and 922 controls from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. Relative risks (RRs) and 95% confidence intervals (95% CIs) were calculated. RESULTS: DRB1*13 was found to protect against ACPA-positive RA when stratifying for the shared epitope and using a dominant genetic model (RR 0.41 [95% CI 0.26-0.64]). Furthermore, DRB1*13 neutralized the effect of the shared epitope in ACPA-positive RA (RR 3.91 [95% CI 3.04-5.02] in patients who had the shared epitope but not DRB1*13, and RR 1.22 [95% CI 0.81-1.83] in patients with both the shared epitope and DRB1*13, as compared with patients negative for both the shared epitope and DRB1*13). However, we did not replicate the previous published risk of ACPA-negative RA conferred by DRB1*03 when a dominant genetic model was used (RR 1.29 [95% CI 0.91-1.82]). Similarly, no significant effect of DRB1*03 on RR for ACPA-negative RA was seen using the recessive genetic model (RR 1.18 [95% CI 0.6-2.4]). In contrast, the combination of DRB1*03 and DRB1*13 was significantly associated with increased risk of developing ACPA-negative RA (RR 2.07 [95% CI 1.17-3.67]). CONCLUSION: Our findings indicate that the DRB1*13 allele plays a dual role in the development of RA, by protecting against ACPA-positive RA but, in combination with DRB1*03, increasing the risk of ACPA-negative RA
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| 7. |
- Westerlind, Helga, et al.
(författare)
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Dense genotyping of immune-related loci identifies HLA variants associated with increased risk of collagenous colitis.
- 2017
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Ingår i: Gut. - : BMJ Publishing Group Ltd. - 0017-5749 .- 1468-3288. ; 66:3, s. 421-428
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Collagenous colitis (CC) is a major cause of chronic non-bloody diarrhoea, particularly in the elderly female population. The aetiology of CC is unknown, and still poor is the understanding of its pathogenesis. This possibly involves dysregulated inflammation and immune-mediated reactions in genetically predisposed individuals, but the contribution of genetic factors to CC is underinvestigated. We systematically tested immune-related genes known to impact the risk of several autoimmune diseases for their potential CC-predisposing role.DESIGN: Three independent cohorts of histologically confirmed CC cases (N=314) and controls (N=4299) from Sweden and Germany were included in a 2-step association analysis. Immunochip and targeted single nucleotide polymorphism (SNP) genotype data were produced, respectively, for discovery and replication purposes. Classical human leucocyte antigen (HLA) variants at 2-digit and 4-digit resolution were obtained via imputation from single marker genotypes. SNPs and HLA variants passing quality control filters were tested for association with CC with logistic regression adjusting for age, sex and country of origin.RESULTS: Forty-two markers gave rise to genome-wide significant association signals, all contained within the HLA region on chromosome 6 (best p=4.2×10(-10) for SNP rs4143332). Among the HLA variants, most pronounced risk effects were observed for 8.1 haplotype alleles including DQ2.5, which was targeted and confirmed in the replication data set (p=2.3×10(-11); OR=2.06; 95% CI (1.67 to 2.55) in the combined analysis).CONCLUSIONS: HLA genotype associates with CC, thus implicating HLA-related immune mechanisms in its pathogenesis.
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