| 1. |
- Ahmad, Awais, 1987-
(author)
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Autoantibodies in healthy blood donors, rheumatic and autoimmune liver diseases
- 2024
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Doctoral thesis (other academic/artistic)abstract
- Autoimmunity is a common phenomenon where the immune system recognises the body's own tissues. Autoimmunity can lead to disease if tissue damage occurs. Autoimmune diseases affect 5–10% of the global population and in many of these autoantibodies can be detected. The autoantibodies can be detected with several different methods. In this thesis, line immunoassays and fluorescence enzyme immunoassay were used to investigate the presence of autoantibodies in blood donors and various disease groups. Line immunoassays use strips while fluorescence enzyme immunoassay uses wells. The strips and wells are coated with proteins that are allowed to react with serum samples from the patient. In the presence of autoantibodies, either a color change (line immunoassay) or a light reaction (fluorescence enzyme immunoassay) occurs.Study I and II: With the EuroLine -Autoimmune Liver Diseases- (IgG) line immunoassay, the presence of autoantibodies associated with autoimmune liver diseases was analysed in blood donors, patients with autoimmune liver diseases and patients with SLE. Autoantibodies could be detected in several blood donors. A very rare autoantibody, anti-LC- 1, was more common in blood donors than in patients with autoimmune liver diseases. Despite the presence of the autoantibodies, no association was seen with abnormal liver values in blood donors or patients with SLE. By raising the cut-off, the number of "false positive" results decreased. However, this could not correct the problem with anti-LC-1, which seems to indicate that there is a problem with the LC-1 antigen so that non-specific reactions are detected. The risk of developing autoimmune liver disease was considered to be low in the SLE patients, as none of these patients developed autoimmune liver disease despite several years of follow-up. Most of the positive findings with the EuroLine immunoassay could not be confirmed with other methods, indicating that this method is very sensitive.Study III: With the EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) line immunoassay, the rare autoantibodies anti-Th/To and anti-NOR90 could be detected as frequently in blood donors as in patients with systemic sclerosis. Most of the other autoantibodies were more common in patients with systemic sclerosis compared to blood donors and other disease groups. Some of these autoantibodies were associated with specific clinical manifestations, including renal involvement in patients with SLE. These findings need to be verified.Study IV: Autoantibodies that bind the U1-RNP protein (anti-U1-RNP) can be detected in patients with SLE. Patients with anti-U1-RNP can be further analysed for the presence of autoantibodies against the protein RNP 70kDa (anti-RNP70). However, the clinical value of further analysis of anti-RNP70 is uncertain. In this study, fluorescence enzyme immunoassay was used to analyse anti-U1-RNP positive samples for anti-RNP70 to evaluate whether it added anything of clinical value in SLE patients. Presence of anti-U1-RNP was associated with low white blood cell counts and less organ damage. However, analysis of anti-RNP70 in patients with SLE did not add any additional clinical information.Conclusion: Euroline -Autoimmune Liver Diseases- (IgG) and EuroLine Systemic Sclerosis (Nucleoli) Profile (IgG) are tools that are of value in the diagnosis of autoimmune liver diseases and systemic sclerosis, but the methods have high sensitivity which can lead to false positive results. By raising the cut-off, the risk of this can be reduced. Some rare antibodies were found more frequently in blood donors than in patients with the different disease groups, suggesting potential problems with the antigen source. Subtyping of anti-RNP70 in SLE patients with anti-U1-RNP did not add anything of clinical value.
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| 2. |
- Enocsson, Helena, 1982-
(author)
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Biomarkers and mediators in systemic lupus erythematosus : IFNα versus the CRP response, and evaluation of suPAR and anti-dsDNA antibody assays
- 2014
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Doctoral thesis (other academic/artistic)abstract
- Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease which may affect multiple organ systems. Interferon alpha (IFNα) and autoantibodies that form immune complexes with nuclear antigens (ANA) are hallmarks believed to drive the disease into a vicious circle of inflammation, tissue damage, autoantigen exposure and autoantibody production.In SLE, the disease course is characterized by episodes of exacerbations alternating with remissions. In order to best treat the patient it is important to closely monitor symptoms and signs of disease activity. Because of the disease heterogeneity, no single biomarker has yet been found to reflect SLE disease activity in general, although antidouble stranded DNA (anti-dsDNA) antibodies sometimes indicate activity, primarily with renal involvement, and constitutes an item of the SLE disease activity score SLEDAI-2K. However, the method of anti-dsDNA measurement is not standardized and therefore varies between different laboratories. In many other inflammatory conditions, such as rheumatoid arthritis and during bacterial infections, the C-reactive protein (CRP) level is a good indicator of ongoing inflammation, but in SLE and during viral infections, CRP commonly fails to reflect the degree of inflammation. Both viral infections and SLE are characterized by IFNα, and we thus aimed to elucidate whether IFNα can inhibit CRP production. Further, four assays for anti-dsDNA antibody measurements were evaluated with regard to SLE disease specificity and activity, and a new potential biomarker of inflammation, the soluble urokinase plasminogen activator receptor (suPAR), was assessed in relation to disease activity and organ damage.An in vitro inhibitory effect of IFNα on CRP transcription and production was found in hepatocytes, and this was consolidated by in vivo studies of CRP and IFNα in sera from well-characterized SLE patients (KLURING; Kliniskt lupusregister i nordöstra Götaland). Here, CRP and disease activity were associated among patients without IFNα and without a CRP lowering gene variant (SNP rs1205). The poor disease activity compliance of CRP could therefore be explained, at least in part, by polymorphisms in the CRP gene and increased levels of IFNα. Critical differences between the methods measuring anti-dsDNA were found regarding disease specificity and ability to reflect disease activity and the results suggests the Crithidia luciliae immunofluorescence test (CLIFT) for diagnostic purposes and a bead-based multiplex assay (FIDIS) for monitoring of disease activity. Evaluation of suPAR in SLE revealed no association of suPAR with disease activity, but interestingly instead with accumulated organ damage. suPAR could therefore possibly be used to advert patients at high risk of organ damage.A detailed biological and clinical characterization of established and emerging SLE biomarkers is of importance since it may improve the clinical management as well as increase the knowledge about disease mechanisms.
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| 3. |
- Frodlund, Martina, 1978-
(author)
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Antinuclear and antiphospholipid antibodies versus disease manifestations and clinical outcomes in systemic lupus erythematosus
- 2020
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Doctoral thesis (other academic/artistic)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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| 4. |
- Sjöwall, Christopher, 1975-
(author)
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C-reactive protein (CRP) and anti-CRP autoantibodies in systemic lupus erythematosus : a study on the occurrence and clinical implications of anti-CRP antibodies and CRP-mediated complement activation
- 2006
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Doctoral thesis (other academic/artistic)abstract
- Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by production of a wide range of autoantibodies, multiple organ involvement and by local formation or tissue deposition of immune complexes (ICs) in the inflamed organs. In contrast to most systemic inflammatory conditions, and despite raised levels of pro-inflammatory cytokines, SLE flares are rarely reflected by elevated C-reactive protein (CRP), an important acute-phase reactant in man with homologs in vertebrates and several invertebrates. As a part of the innate immune system, CRP binds certain molecules exposed on the surface of dying cells/apoptotic bodies and on the surface of pathogens and mediates their elimination by uptake in the reticuloendothelial system. CRP also interacts with IgG-containing immune complexes, binds Fc receptors and activates the complement system via C1q.The aims of this thesis were to investigate the complement activation properties of CRP; to elucidate if anti-CRP antibodies occur in SLE and, if so, whether anti-CRP antibody levels correlate with disease activity in SLE; to test the hypothesis that autoantibodies to pro-inflammatory cytokines prevent rise of CRP; and to survey if autoantibodies to certain nuclear antigens or to CRP correlate with cytokine-inducing properties of ICs from SLE sera.We have demonstrated that CRP bound to phosphorylcholine is a powerful activator of the classical complement pathway already in the CRP concentration range 4 to 10 mg/L, but with a marked inhibition at CRP levels above 150 mg/L. Autoantibodies to the monomeric form of CRP were found in approximately 40 percent of SLE patients and in a few sera from patients with primary Sjögren’s syndrome, but not in rheumatoid arthritis or in inflammatory bowel disease. The anti-CRP antibody levels showed significant correlations to several laboratory and clinical measurements, and anti-CRP positivity was associated with renal involvement in SLE. Native CRP levels were not correlated with anti-CRP or anti-cytokine antibody levels. Hence, the presence of antibodies to monomeric CRP or to CRP-inducing cytokines is an unlikely explanation to the relative failure of CRP response in patients with active lupus. However, antibodies to TNFα were found in subnormal levels at disease flares, whereas antibodies to TGFβ were found in supranormal levels as compared to healthy subjects. In contrast to antibodies against CRP and DNA, anti-SSA and anti-SSB antibodies may regulate the inflammatory process in SLE by enhancing IC formation and subsequent production of cytokines such as IL-6, IL-10 and IL-12p40. Hypothetically, anti-CRP autoantibodies may be of pathogenic importance, for instance by binding to monomeric CRP on cell and tissue surfaces and thereby increasing the risk of extrahepatic deposition of apoptotic material and in situ formation of ICs.
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| 5. |
- Svensson, Christina, 1964-
(author)
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Ultrasound Assessment and Vascular Mechanics in Takayasu Arteritis and Systemic Lupus Erythematosus
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Takayasu arteritis (TAK) and systemic lupus erythematosus (SLE) are inflammatory diseases that primarily affect young women. TAK is a rare vasculitis that affects the aorta and its main branches, whereas SLE is a chronic autoimmune disease that effects multiple organs. Both diseases are associated with premature cardiovascular disease (CVD), and a wish to understand these associations prompted the studies of this thesis.The macrocirculation, microcirculation and vascular haemodynamics were studied in patients with TAK (N=25 in Paper I, N=17 in Paper II) and SLE (N=60 in Papers III and IV), and compared with age- and gender-matched controls. Vessel wall thickness (intima-media thickness (IMT)), vessel wall appearance, and occurrence of atherosclerotic plaques were evaluated in multiple vascular areas using high-frequency ultrasound (US). Microcirculation in the skin was studied after induced ischaemia employing a new method that combines laser Doppler flowmetry (LDF) and diffuse reflectance spectroscopy (DRS). The measured microcirculatory value was defined as the peak oxygen saturation (OxyP). Pulse wave analysis was used for calculation of the central augmentation index (AIx). Cerebrovascular reserve capacity (CVR) was analysed using transcranial Doppler (TCD).Paper IIn this study, TAK patients were examined with US, including follow-up studies. Clinically active cases of TAK showed significantly increased IMT compared to stable patients with TAK and healthy controls. The arteries of patients with active disease showed signs of intra-mural micro-vessels, oedema, or increased vessel diameter, whereas these signs were not seen in cases of stable disease. The Takayasu US index (based on the summation of the IMT in three arterial areas) was higher in active disease than in stable disease, and was valuable for the assessment of relapse.Paper IIIn this study of vascular haemodynamics in patients with TAK we observed impaired microcirculation, as compared with controls. CVR was preserved regardless of proximal arterial stenosis. The AIx, reflecting arterial stiffness, was increased, also in the arms without proximal stenosis or occlusion.Papers III and IVIncreased IMT with predominantly medium echogenicity was observed in multiple arteries of the 60 patients with SLE, predominantly in vascular areas that are not usually part of the IMT measurements. The patients with SLE developed plaques more frequently and earlier in life compared to the controls. Correlation with traditional cardiovascular risk factors was observed, indicating atherosclerotic mechanisms rather than inflammation. The patients with SLE had higher AIx values and lower OxyP levels, even at younger ages, and both these methods correlated with the IMT and plaque occurrence.ConclusionsFor patients with TAK, US can be valuable both for the diagnosis of the disease and for distinguishing between the active and stable disease forms. The microcirculation and degree of arterial stiffness in the arms are affected also in patients with TAK without proximal stenosis/occlusion, indicating a more widespread arterial wall dysfunction.In patients with SLE, increased IMT, an affected microcirculation, increased arterial stiffness, and premature atherosclerotic plaques indicate vascular affection coupled with increased risk for cardiovascular disease. All these evaluated methods may be used for longitudinal studies with or without intervention.
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| 6. |
- Wirestam, Lina, 1986-
(author)
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Biomarkers of disease activity and organ damage in systemic lupus erythematosus
- 2017
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Doctoral thesis (other academic/artistic)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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