| 1. |
- Enocsson, Helena, et al.
(författare)
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Soluble urokinase plasminogen activator receptor (suPAR) levels predict damage accrual in patients with recent-onset systemic lupus erythematosus
- 2020
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Ingår i: Journal of Autoimmunity. - : Elsevier BV. - 0896-8411 .- 1095-9157. ; 106
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The soluble urokinase plasminogen activator receptor (suPAR) has potential as a prognosis and severity biomarker in several inflammatory and infectious diseases. In a previous cross-sectional study, suPAR levels were shown to reflect damage accrual in cases of systemic lupus erythematosus (SLE). Herein, we evaluated suPAR as a predictor of future organ damage in recent-onset SLE. Methods: Included were 344 patients from the Systemic Lupus International Collaborating Clinics (SLICC) Inception Cohort who met the 1997 American College of Rheumatology classification criteria with 5-years of follow-up data available. Baseline sera from patients and age- and sex-matched controls were assayed for suPAR. Organ damage was assessed annually using the SLICC/ACR damage index (SDI). Results: The levels of suPAR were higher in patients who accrued damage, particularly those with SDI≥2 at 5 years (N = 32, 46.8% increase, p = 0.004), as compared to patients without damage. Logistic regression analysis revealed a significant impact of suPAR on SDI outcome (SDI≥2; OR = 1.14; 95% CI 1.03–1.26), also after adjustment for confounding factors. In an optimized logistic regression to predict damage, suPAR persisted as a predictor, together with baseline disease activity (SLEDAI-2K), age, and non-Caucasian ethnicity (model AUC = 0.77). Dissecting SDI into organ systems revealed higher suPAR levels in patients who developed musculoskeletal damage (SDI≥1; p = 0.007). Conclusion: Prognostic biomarkers identify patients who are at risk of acquiring early damage and therefore need careful observation and targeted treatment strategies. Overall, suPAR constitutes an interesting biomarker for patient stratification and for identifying SLE patients who are at risk of acquiring organ damage during the first 5 years of disease.
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| 2. |
- Frodlund, Martina, 1978-
(författare)
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Antinuclear and antiphospholipid antibodies versus disease manifestations and clinical outcomes in systemic lupus erythematosus
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) has an exceptionally heterogeneous clinical spectrum, ranging from mild disease limited to skin and joints to severe manifestations with renal disorder, central nervous system disease, severe cytopenias and thromboembolic events. Important clinical challenges include the prediction of disease flares and the identification of individuals that are likely to evolve severe disease with accrual of organ damage and worse prognosis. Autoantibodies, i.e. antinuclear antibodies (ANA) and antiphospholipid antibodies (aPL), and interferon alpha (IFN-α) that contribute to formation of immune complexes with nuclear antigens, are hallmarks considered to drive the disease in a vicious circle of antigen exposure, autoantibody production, inflammation and organ damage. There are few good biomarkers to predict severe SLE and organ damage. The aim of this PhD project was thus to increase the knowledge regarding ANA as well as aPL, and other potential biomarkers in relation to clinical features and disease outcomes in SLE.As expected, we found that the homogeneous ANA staining pattern was most common, and that it was associated with the occurrence of the ‘immunological disorder’ criterion. Speckled ANA was the second most common staining pattern, and it was inversely associated with arthritis, the ‘immunological disorder’ criterion and organ damage (Paper I). We also demonstrated that a considerable proportion of the patients lost ANA-positivity over time, whereas consistent staining patterns were most frequent (Paper V).Survival of patients with SLE has improved. Yet, in comparison to the general population, irreversible organ damage and increased mortality remains a critical concern. In Paper II, our cross-sectional analysis showed that more than a quarter of the patients had any aPL isotype (IgG, IgM or IgA class), and 14% were classified with antiphospholipid antibody syndrome (APS). A positive lupus anticoagulant (LA) test and/or IgG aPL tests were associated with most APS-related events and organ damage. Lupus nephritis, tobacco smoking, LA-positivity and the use of statins and/or corticosteroids were strongly associated with damage accrual, while hydroxychloroquine seemed to be protective. IgA aPL was not uncommon (16%) in Swedish cases of SLE, and analysis of IgA aPL may add information among clinically suspected APS-patients testing negative for LA and other aPL isotypes.Despite modern management and tax-funded health care with universal access, almost two thirds of the patients accrued organ damage over time, and the main causes of death were identified as malignancy, infection, and cardiovascular disease. We could confirm well established risk factors for organ damage such as APS, hypertension, and/or the use of corticosteroids, but we also observed that other factors such as pericarditis, haemolytic anaemia, lymphopenia and myositis seems to be of importance in this view (Paper IV).We also demonstrated that levels of the extracellular matrix protein osteopontin (OPN) was correlated with disease activity in patients with recent-onset SLE. In addition, OPN levels reflected global organ damage and were associated with APS and could have potential as a valuable biomarker in SLE (Paper III).Additional studies are warranted to further establish the clinical and mechanistic relevance of ANA seroconversion, OPN, as well as the importance of IgA aPL. Vigilance for malignancies, a restricted use of corticosteroids and prevention of cardiovascular disease and APS events are among modifiable factors to prevent organ damage and premature mortality.This thesis emphasizes the importance of autoantibodies in the pathogenesis, and diagnosis, of SLE. The autoantibody profile can be of great importance for tailored therapy in order to minimize the risk of organ damage accrual, morbidity as well as mortality.
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| 3. |
- Frodlund, Martina, 1978-, et al.
(författare)
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Longitudinal anti-nuclear antibody (ANA) seroconversion in systemic lupus erythematosus : a prospective study of Swedish cases with recent-onset disease
- 2020
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Ingår i: Clinical and Experimental Immunology. - : WILEY. - 0009-9104 .- 1365-2249. ; 199:3, s. 245-254
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Tidskriftsartikel (refereegranskat)abstract
- Serum immunoglobulin (Ig)G anti-nuclear antibodies (ANA) detected by indirect immunofluorescence (IF) microscopy remains a hallmark of systemic lupus erythematosus (SLE). Whether or not IF-ANA status varies over time is controversial. We therefore designed a prospective study with longitudinal follow-up of patients with recent-onset SLE. The study population consisted of 54 recently diagnosed SLE cases, all meeting the 1982 American College of Rheumatology (ACR) and/or the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria. Clinical follow-up data, including disease activity, organ damage and sera, were collected from clinical onset of SLE and onwards, in most cases yearly (0-96 months). IF-ANA was analysed on human epithelial cells-2 (HEp-2) cells and categorized regarding staining patterns. Using an addressable laser bead assay (FIDIS (TM) Connective profile), we measured IgG-ANA fine specificities against Ro52/SSA, Ro60/SSA, Sjogren's syndrome type B antigen (La/SSB), Smith antigen (Sm), Smith antigen/ribonucleoprotein (Sm/RNP), U1 RNP (U1RNP), dsDNA, ribosomal-P protein and histone. At baseline, all patients were judged ANA-positive at an abnormal titre corresponding to the 95th percentile of healthy blood donors, but seven of 54 patients (13%) lost ANA-positivity over time. Homogeneous (AC-1; 46%) and speckled (AC-4 or 5; 31%) were the most frequently observed patterns at inclusion, whereas 7% switched pattern at least once during follow-up. Established associations between ANA fine specificities and clinical data were confirmed. Levels of anti-Sm/RNP, but not of anti-dsDNA, correlated with clinical disease activity [modified SLE disease activity 2000 (mSLEDAI-2K)]. Our data indicate that a considerable proportion of Swedish patients with SLE lose ANA-positivity over time, whereas consistent staining patterns were frequent. The clinical and mechanistic relevance of ANA seroconversion remains uncertain. Further prospective evaluations in larger SLE populations with more diverse ethnicities are warranted.
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| 4. |
- Martinsson, Klara, et al.
(författare)
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Elevated free secretory component in early rheumatoid arthritis and prior to arthritis development in patients at increased risk
- 2020
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Ingår i: Rheumatology. - : Oxford University Press. - 1462-0324 .- 1462-0332. ; 59:5, s. 979-987
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. Considering growing evidence of mucosal involvement in RA induction, this study investigated circulating free secretory component (SC) in patients with either recent-onset RA or with ACPA and musculoskeletal pain. Methods. Two prospective cohorts were studied: TIRA-2 comprising 452 recent-onset RA patients with 3 years of clinical and radiological follow-up, and TIRx patients (n = 104) with ACPA IgG and musculoskeletal pain followed for 290 weeks (median). Blood donors and three different chronic inflammatory diseases served as controls. Free SC was analysed by sandwich ELISA. Results. Serum levels of free SC were significantly higher in TIRA-2 patients compared with TIRx and all control groups (P < 0.01). Among TIRx patients who subsequently developed arthritis, free SC levels were higher compared with all control groups (P < 0.05) except ankylosing spondylitis (P = 0.74). In TIRA-2, patients with ACPA had higher baseline levels of free SC compared with ACPA negative patients (P < 0.001). Free SC status at baseline did not predict radiographic joint damage or disease activity over time. In TIRx, elevated free SC at baseline trendwise associated with arthritis development during follow-up (P = 0.066) but this disappeared when adjusting for confounders (P = 0.72). Cigarette smoking was associated with higher levels of free SC in both cohorts. Conclusion. Serum free SC levels are increased in recent-onset RA compared with other inflammatory diseases, and associate with ACPA and smoking. Free SC is elevated before arthritis development among ACPA positive patients with musculoskeletal pain, but does not predict arthritis development. These findings support mucosal engagement in RA development.
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| 5. |
- Skoglund, Caroline, 1981-, et al.
(författare)
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C-reactive protein and C1q regulate platelet adhesion and activation on adsorbed immunoglobulin G and albumin.
- 2008
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Ingår i: Immunology and cell biology. - : Wiley. - 0818-9641 .- 1440-1711. ; 86:5, s. 466-74
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Tidskriftsartikel (refereegranskat)abstract
- Blood platelets and C-reactive protein (CRP) are both used clinically as markers of ongoing inflammation, and both participate actively in inflammatory responses, although the biological effects are still incompletely understood. Rapidly adhering platelets express receptors for complement factor 1q (C1q) and the Fc part of immunoglobulin G (IgG), and CRP is known to activate/regulate complement via C1q binding, and to ligate FcgammaRs. In the present study, we used normal human IgG pre-adsorbed to a well-characterized methylated surface as a model solid-phase immune complex when investigating the effects of CRP and C1q on platelet adhesion and activation. Protein adsorption was characterized using ellipsometry and polyclonal antibodies, and human serum albumin (HSA) and non-coated surfaces were used as reference surfaces. Platelet adhesion to IgG and HSA was inhibited by both C1q and CRP. Furthermore, CRP (moderately) and C1q (markedly) decreased the spreading of adhering platelets. The combination of C1q and CRP was slightly more potent in reducing cell adhesion to IgG, and also impaired the adhesion to HSA and non-coated surfaces. Platelet production of thromboxane B2 (TXB(2)) was also reduced by C1q both in the presence and absence of CRP, whereas CRP alone had no effect on TXB(2) production. We conclude that CRP and C1q regulate the behaviour of platelets, and that this may be an important immunoregulatory mechanism during inflammatory conditions.
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| 6. |
- Wirestam, Lina, 1986-
(författare)
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Biomarkers of disease activity and organ damage in systemic lupus erythematosus
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Systemic lupus erythematosus (SLE) is a systemic inflammatory disease. Clinically, the distinction between ongoing inflammation attributed to SLE, and organ damage due to medication or co-morbidities remains challenging. In addition, SLE is a heterogeneous disease where the various disease phenotypes complicate the search for biomarkers that adequately reflect disease activity and/or signs of increasing organ damage. The aim of the thesis was to investigate and evaluate potential new biomarkers of disease activity and/or organ damage in SLE patients.High mobility group box protein-1 (HMGB1) is a nuclear non-histone protein that can shuttle to the cytoplasm, become secreted extracellularly, and participate in systemic inflammation. Administration of monoclonal anti-HMGB1 antibodies has been reported both to attenuate and intensify disease in animal models of arthritis and lupus. In Paper I of the thesis, circulating anti-HMGB1 was found in 23% of the SLE patients and correlated with disease activity variables. The biological role of these autoantibodies remains to be elucidated.As a consequence of massive circulating levels of cellular debris and immune complexes, SLE patients have insufficient capacity to remove such material via the reticuloendothelial system. Pentraxin 3 (PTX3) may possibly protect against lupus flares due to classical complement activation, opsonization of apoptotic cells, and cytokine induction. In Paper II, circulating PTX3 was found to be inhibited or exhausted by interferon (IFN)-α, a key cytokine of SLE pathogenesis, and serum levels of PTX3 in SLE patients were inversely related to IFN-α levels. Suppressed PTX3 levels may contribute to a vicious circle resulting in impaired waste clearance, autoantigen exposure and autoantibody production, and sustained disease activity.Osteopontin (OPN), a protein known to influence cell signaling and apoptosis, has been proposed as a marker of organ damage in pediatric lupus. In a Swedish cross-sectional study, circulating OPN levels were found to be raised in SLE (Paper III). In patients with recent-onset disease, OPN reflected disease activity, while in established disease, OPN appeared to mirror damage accrual and cardiovascular damage. In Paper IV, OPN was instead analyzed in an international longitudinal multi-center study based on patients with recent-onset SLE and follow-up data. OPN turned out to be a poor predictor of organ damage, but significant associations were observed between OPN and disease activity both at disease onset, as well as over 5 years of follow-up.In conclusion, increased anti-HMGB1 antibody and decreased PTX3 levels could potentially sustain the impaired waste-disposal. Of the molecules analyzed in this thesis, OPN seems to be the best marker of disease activity. Further studies of these proteins may help to better understand SLE pathogenesis and to optimize treatment of patients.
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