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| 2. |
- Lood, Christian, et al.
(författare)
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C1q inhibits immune complex-induced interferon-alpha production in plasmacytoid dendritic cells : a novel link between C1q deficiency and systemic lupus erythematosus pathogenesis
- 2009
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Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 60:10, s. 3081-3090
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: C1q deficiency is the strongest risk factor known for the development of systemic lupus erythematosus (SLE), since almost all humans with a genetic deficiency of C1q develop this disease. Low C1q serum concentration is also a typical finding in SLE during flares, emphasizing the involvement of C1q in SLE pathogenesis. Recent studies have revealed that C1q has a regulatory effect on Toll-like receptor-induced cytokine production. Therefore, we undertook this study to investigate whether C1q could regulate production of interferon-alpha (IFNalpha). METHODS: Peripheral blood mononuclear cells (PBMCs) and plasmacytoid dendritic cells (PDCs) were stimulated with 3 known interferogenic stimuli and cultured with physiologic concentrations of C1q. IFNalpha production was determined by an immunoassay. RESULTS: C1q significantly inhibited PBMC IFNalpha production induced by RNA-containing immune complexes (ICs), herpes simplex virus (HSV), and CpG DNA. C1q also inhibited PDC IFNalpha production induced by ICs and CpG DNA but increased PDC IFNalpha production induced by HSV. The regulatory role of C1q was not specific for IFNalpha but was also seen for interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha. We demonstrated binding of C1q to PDCs both by surface plasmon resonance interaction analysis and by flow cytometry, and we also demonstrated intracellular detection of 2 C1q binding proteins. CONCLUSION: Our findings contribute to the understanding of why C1q deficiency is such a strong risk factor for SLE and suggest an explanation for the up-regulation of the type I IFN system seen in SLE patients.
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| 5. |
- Bengtsson, Anders, et al.
(författare)
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SLE serum induces classical caspase-dependent apoptosis independent of death receptors
- 2008
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Ingår i: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 126:1, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- The main source of autoantigens in systemic lupus erythematosus (SLE) is most likely apoptotic material. We have previously shown that sera from SLE patients can induce apoptosis in monocytes and lymphocytes, and here we characterized mechanisms of apoptosis induced by SLE serum. SLE serum seems to induce caspase-dependent classical apoptosis since cells exposed to SLE serum displayed morphology consistent with classical apoptosis as demonstrated by confocal microscopy, and pan-caspase inhibitor Z-VAD.fmk significantly reduced SLE serum-induced apoptosis. Death-receptor-independent pathways seemed to be involved since SLE serum induced apoptosis equally in FADD-mutant and wild-type Jurkat cell lines, and blocking of Fas and TNFR1 did not reduce apoptosis induction. Importantly, apoptosis was significantly reduced in a Bcl-2 overexpressing Jurkat cell line indicating involvement of mitochondrial pathways. Thus, based on morphology and caspase inhibition experiments, we have demonstrated that SLE serum induce classical caspase-dependent apoptosis, and this was independent of death receptor pathways.
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| 7. |
- Gullstrand, Birgitta, et al.
(författare)
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Complement classical pathway components are all important in clearance of apoptotic and secondary necrotic cells.
- 2009
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Ingår i: Clinical and Experimental Immunology. - : Oxford University Press (OUP). - 0009-9104 .- 1365-2249. ; 156, s. 303-311
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Tidskriftsartikel (refereegranskat)abstract
- Summary Inherited deficiencies in components of the classical complement pathway are strong disease susceptibility factors for the development of systemic lupus erythematosus (SLE) and there is a hierarchy among deficiency states, the strongest association being with C1q deficiency. We investigated the relative importance of the different complement pathways regarding clearance of apoptotic cells. Phagocytosis of labelled apoptotic Jurkat cells by monocyte-derived macrophages in the presence of sera from individuals with complement deficiencies was studied, as well as C3 deposition on apoptotic cells using flow cytometry. Sera from individuals deficient in C1q, C4, C2 or C3 all showed decreased phagocytosis. Mannose binding lectin (MBL) and the alternative pathway did not influence phagocytosis. Notably, the components of the complement classical pathway, including C1q, were equally important in clearance of apoptotic cells. This indicates that deposition of C3 fragments is of major significance; we therefore studied C3 deposition on apoptotic cells. Experiments with MBL-deficient serum depleted of C1q or factor D confirmed the predominance of the classical pathway. At low dilution, sera deficient of C1q, C4 or C2 supported C3 fragment deposition demonstrating alternative pathway activation. In conclusion, we have found that complement-mediated opsonization and phagocytosis of apoptotic cells, particularly those undergoing secondary necrosis, are dependent mainly upon an intact classical pathway. The alternative pathway is less important, but may play a role in some conditions. C1q was not more important than other classical pathway components, suggesting a role in additional pathogenetic processes in SLE other than clearance of apoptotic cells.
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| 8. |
- Jönsen, Andreas, et al.
(författare)
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Association between SLE nephritis and polymorphic variants of the CRP and Fc gamma RIIIa genes
- 2007
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Ingår i: Rheumatology. - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 46:9, s. 1417-1421
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To study the relationship between clinical manifestations in systemic lupus erythematosus (SLE) with polymorphisms in suggested susceptibility genes encoding Fc gamma RIIa, Fc gamma RIIIa, Fc gamma RIIIb, CRP and IL-1Ra. Methods. Genetic polymorphisms were analysed in 323 unrelated SLE patients and 200 healthy blood donors. The genotype frequencies were compared between clinical subsets of SLE patients, as well as with healthy controls. Clinical manifestations included the ACR classification criteria. Nephritis was further classified according to WHO class on renal biopsy. Results. Presence of a CRP4 A-allele was associated with SLE nephritis (P< 0.01) and inversely correlated with arthritis (P < 0.01), when comparing within the SLE group. The Fc gamma RIIIa F/F genotype was also associated with nephritis (WHO class III and IV, P=0.04 for the SLE group) and in combination with the CRP4 A-allele a stronger association was noted (P<0.001). Furthermore, the Fc gamma RIIIb NA2/NA2 genotype was associated with butterfly rash (P< 0.01). An association was found between seizures and the presence of both the Fc gamma RIIa R/R and the Fc gamma RIIIa F/F genotypes (P< 0.01) and an inverse correlation between serositis and the CRP4 A-allele when present together with the IL-1Ra 2-allele (P=0.01). Furthermore, a combination of the Fc gamma RIIa R/R genotype and CRP4 A-allele was associated with lymphopenia (P= 0.02) and a similar result was found for the combination of Fc gamma RIIIa F/F and Fc gamma RIIIb NA2/NA2 (P= 0.04). Conclusions. Polymorphic variants of the CRP and Fc gamma-receptor genes are associated with the clinical phenotype in SLE. Our findings suggest an immune complex-mediated pathogenesis in nephritis and seizures, while development of arthritis may depend on other pathogenetic pathways.
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| 9. |
- Jönsen, Andreas, et al.
(författare)
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Genetically determined mannan-binding lectin deficiency is of minor importance in determining susceptibility to severe infections and vascular organ damage in systemic lupus erythematosus.
- 2007
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Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 16:4, s. 245-253
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Tidskriftsartikel (refereegranskat)abstract
- Deficiency of mannan-binding lectin (MBL) has been reported to impact susceptibility to severe nfections and atherosclerosis in systemic lupus erythematosus (SLE). In this study, MBL gene polymorphisms were analysed in 143 SLE patients and the frequency of severe infections and organ damage according to SLICC/ACR Damage Index regarding cerebrovascular accidents, angina pectoris, coronary by-pass surgery, myocardial infarction and peripheral arterial disease leading to significant tissue loss, were recorded during a mean follow-up time of 15 years from diagnosis. In a multiple logistic regression model, smoking (P = 0.001), hypertension (P = 0.030), alcohol intake (P = 0.027) and higher triglyceride concentration (P = 0.026) were associated with cerebrovascular, cardiovascular and peripheral arterial organ damage (CPAD), while the association with MBL deficiency did not reach significance (P = 0.098). Alcohol intake (> 15 g/month) was inversely correlated with CPAD (OR = 0.29, 95%Cl 0.096-0.87). MBL deficiency was not significantly more common in SLE patients with severe infections in a multivariate analysis (P > 0.3). In conclusion, classical risk factors such as smoking, hypertension, low alcohol intake and elevated triglyceride concentration were relatively more important for development of CPAD than MBL deficiency in SLE. Furthermore, MBL deficiency did not contribute to development of major infections in SLE.
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| 10. |
- Jönsson, Göran, et al.
(författare)
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Vaccination against encapsulated bacteria in hereditary C2 deficiency results in antibody response and opsonization due to antibody-dependent complement activation.
- 2012
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Ingår i: Clinical Immunology. - : Elsevier BV. - 1521-6616. ; 144:3, s. 214-227
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Tidskriftsartikel (refereegranskat)abstract
- Hereditary C2 deficiency (C2D) is an important susceptibility factor for invasive infections caused by encapsulated bacteria such as pneumococci and Haemophilus influenzae type b. The infections are mostly seen in childhood indicating that antibody-mediated acquired immunity is affected. C2D persons and healthy controls were vaccinated with ActHIB® and Pneumo23®. Analysis of specific antibodies to pneumococci serotype 6B, 7F, and 23F, and Hib was performed. Post-vaccination IgG antibodies against pneumococci serotype 6B and 23F at a concentration ≥1.0mg/L was found in similar frequency in C2D persons and controls. Post-vaccination sera from C2D persons showed poor complement-mediated opsonization and phagocytosis of pneumococci by granulocytes when depending on classical and lectin pathway activation only, but increased (p=0.007) and equaled that of the normal controls when also alternative pathway activation was allowed due to antibody-dependent C2 bypass activation. In conclusion, the C2D persons benefited from the vaccination and achieve an increased phagocytic capacity.
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