1.
Alkaissi, Hammoudi, 1983-
(författare)
Identification of candidate genes involved in Mercury Toxicokinetics and Mercury Induced Autoimmunity
2018
Doktorsavhandling (övrigt vetenskapligt/konstnärligt) abstract
BACKGROUND: Autoimmune diseases require the involvement and activation of immune cells and occur when the body builds up an immune response against its own tissues. This process takes place due to the inability to distinguish self-antigen from foreign antigen. Systemic autoimmunity represents an important cause of morbidity and mortality in humans. The mechanisms triggering autoimmune responses are complex and involve a network of genetic factors. Genome wide association study (GWAS) is a powerful method, used to identify genetic risk factors in numerous diseases, such as systemic autoimmune diseases. The goal of GWAS is to identify these genetic risk factors in order to make predictions about who is at risk and investigate the biological process of disease susceptibility. There are several valuable mouse models to investigate the underlying mechanisms causing systemic autoimmune diseases in which mercury induced autoimmunity (HgIA) is a well- established and relevant model. HgIA in mice includes development of autoantibodies, immune complex glomerulonephritis, lymphocyte proliferation, hypergammaglobulinemia and polyclonal B cell activation. In humans, mercury exposure accumulates with considerable concentrations in kidney, liver, and brain. Toxicokinetics of Hg has been studied extensively but the key for inter-individual variation in humans are largely unclear. Differences in accumulation of renal Hg between inbred mouse strains suggest a genetic inter-strain variation regulating retention or/and excretion of Hg.OBJECTIVES: To find loci and candidate genes associated with phenotypes involved in the development of autoimmunity and find candidate genes involved in the regulation of renal Hg excretion.METHODS: MHC II (H-2s) mice were paired (A.SW x B10.S) to obtain F2 offspring exposed to 2.0 or 4.0 mg Hg in drinking water for 6 weeks. Mercury induced autoimmune phenotypes were studied with immunofluorescence (anti-nucleolar antibodies (ANoA)), ELISA anti-DNP/anti-ssDNA (polyclonal B cell activation), anti-chromatin antibodies (ACA) (4.0 mg Hg), and serum IgG1 concentrations. Mercury accumulation in kidney was performed previously and data was included as phenotype. F2 mice exposed to 2.0 mg Hg were genotyped with microsatellites for genome-wide scan with Ion Pair Reverse Phase High Performance Liquid Chromatography (IP RP HPLC). F2 mice exposed to 4.0 mg Hg were genotyped with single nucleotide polymorphisms for genomewide scan with SNP&SEQ technology platform. Quantitative trait loci (QTL) was established with R/QTL. Denaturing HPLC, next generation sequencing, conserved region analysis and genetic mouse strain comparison were used for haplotyping and fine mapping on QTLs associated with Hg concentration in kidney, development of ANoA and serum IgG1 hypergammaglobulinemia. Candidate genes (Pprc1, Bank1 and Nfkb1) verified by additional QTL were further investigated by real time polymerase chain reaction. Genes involved in the intracellular signaling together with candidate genes were included for gene expression analysis.RESULTS: F2 mice exposed to 2.0 mg Hg had low or no development of autoantibodies and showed no significant difference in polyclonal B cell activation in the B10.S and F2 strains. F2 mice exposed to 4.0 mg Hg developed autoantibodies and significantly increased IgG1 concentration and polyclonal B cell activation (anti-DNP). QTL analysis showed a logarithm of odds ratio (LOD) score between 2.9 – 4.36 on all serological phenotypes exposed to 4.0 mg Hg, and a LOD score of 5.78 on renal Hg concentration. Haplotyping and fine mapping associated the development of ANoA with Bank1 (B-cell scaffold protein with ankyrin repeats 1) and Nfkb1 (nuclear factor kappa B subunit 1). The serum IgG1 concentration was associated with a locus on chromosome 3, in which Rxfp4 (Relaxin Family Peptide/INSL5 Receptor 4) is a potential candidate gene. The renal Hg concentration was associated with Pprc1 (Peroxisome Proliferator-Activated Receptor Gamma, Co-activator-Related). Gene expression analysis revealed that the more susceptible A.SW strain expresses significantly higher levels of Nfkb1, Il6 and Tnf than the less susceptible B10.S strain. The A.SW strain expresses significantly lower levels of Pprc1 and cascade proteins than the B10.S strain. Development of ACA was associated with chromosomes 3, 6, 7 and 16 (LOD 3.1, 3.2, 3.4 and 6.8 respectively). Polyclonal B cell activation was associated with chromosome 2 with a LOD score of 2.9.CONCLUSIONS: By implementing a GWAS on HgIA in mice, several QTLs were discovered to be associated with the development of autoantibodies, polyclonal B cell activation and hypergammaglobulinemia. This thesis plausibly supports Bank1 and Nfkb1 as key regulators for ANoA development and HgIA seems to be initiated by B cells rather than T cells. GWAS on renal mercury excretion plausibly supports Pprc1 as key regulator and it seems that this gene has a protective role against Hg.
2.
Wang, Ning, et al.
(författare)
Serological Assessment for Celiac Disease in IgA Deficient Adults
2014
Ingår i: PLOS ONE. - : Public Library of Science. - 1932-6203. ; 9:4, s. 0093180-
Tidskriftsartikel (refereegranskat) abstract
Purpose: Selective immunoglobulin A deficiency is the most common primary immunodeficiency disorder that is strongly overrepresented among patients with celiac disease (CD). IgG antibodies against tissue transglutaminase (tTG) and deamidated gliadin peptides (DGP) serve as serological markers for CD in IgA deficient individuals, although the diagnostic value remains uncertain. The aim of this study was to investigate the prevalence of these markers in a large cohort of IgA deficient adults with confirmed or suspected CD and relate the findings to gluten free diet. Methods: Sera from 488,156 individuals were screened for CD in seven Swedish clinical immunology laboratories between 1998 and 2012. In total, 356 out of 1,414 identified IgA deficient adults agreed to participate in this study and were resampled. Forty-even IgA deficient blood donors served as controls. Analyses of IgG antibodies against tTG and DGP as well as HLA typing were performed and a questionnaire was used to investigate adherence to gluten free diet. Available biopsy results were collected. Results: Out of the 356 IgA deficient resampled adults, 67 (18.8%) were positive for IgG anti-tTG and 79 (22.2%) for IgG anti-DGP, 54 had biopsy confirmed CD. Among the 47 IgA deficient blood donors, 4 (9%) were positive for IgG anti-tTG and 8 (17%) for anti- DGP. Four were diagnosed with biopsy verified CD, however, 2 of the patients were negative for all markers. Sixty-eight of 69 individuals with positive IgG anti-tTG were HLA-DQ2/DQ8 positive whereas 7 (18.9%) of the 37 individuals positive for IgG anti-DGP alone were not. Conclusions: IgG anti- tTG seems to be a more reliable marker for CD in IgA deficient adults whereas the diagnostic specificity of anti-DGP appears to be lower. High levels of IgG antibodies against tTG and DGP were frequently found in IgA deficient adults despite adhering to gluten free diet.
3.
Andraos, Rama, et al.
(författare)
Screening for autoimmune diseases in apparently healthy antinuclear antibody positive individuals
2024
Ingår i: Frontiers in Medicine. - : Frontiers Media S.A.. - 2296-858X. ; 11
Tidskriftsartikel (refereegranskat) abstract
Background: Anti-nuclear antibodies (ANA) assessed by immunofluorescence (IF) microscopy are associated with systemic autoimmune rheumatic diseases (SARD) and can be detected years before onset of clinical symptoms. Recent data indicate dysregulation of the immune system with increased levels of proinflammatory cytokines, including type I interferons (IFN), in ANA-positive versus ANA-negative individuals. Herein, the aims were to investigate IF-ANA, ANA fine specificities, and IFN-α protein levels in relation to self-reported symptoms, as well as clinical signs, of SARD in a large group of healthy blood donors (HBD).Methods: Sera from 825 HBD (48.8% females) were included. IF-ANA was assessed, using HEp-2 cells, according to the routine at the accredited laboratory of Clinical Immunology, Linköping University Hospital. All samples were analyzed for IgG-ANA fine specificities using addressable laser bead assay (ALBIA) at the same laboratory. IFN-α was determined using ELISA. Antibody-positive individuals, and their sex- and age-matched antibody-negative controls, were asked to fill a questionnaire regarding symptoms associated with SARD.Results: In total, 130 HBD (15.8%) were positive with IF-ANA and/or ALBIA. Anti-U1RNP was significantly more common among women. Generally, self-reported symptoms correlated poorly with IF-ANA and/or ALBIA results. Two females with high levels of Ro60/SSA, Ro52/SSA and IFN-α reported mild sicca symptoms and were diagnosed with Sjögren’s disease after clinical evaluation.Conclusion: A considerable proportion of apparently HBD are autoantibody positive, but without clear association to self-reported symptoms. Nevertheless, the combination of autoantibodies, relevant symptoms and high IFN-α levels identified the small proportion of individuals with SARD in the study population.
4.
Brink, Mikael, et al.
(författare)
Multiplex Analyses of Antibodies Against Citrullinated Peptides in Individuals Prior to Development of Rheumatoid Arthritis
2013
Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 65:4, s. 899-910
Tidskriftsartikel (refereegranskat) abstract
Objective The presence of antibodies against cyclic citrullinated peptides has been demonstrated to precede the onset of symptoms of rheumatoid arthritis (RA) by several years. The aim of this study was to analyze antibodies against 10 citrullinated autoantigen-derived peptides for reactivity before the onset of RA symptoms. Methods A casecontrol study was conducted within the Medical Biobank of Northern Sweden. The study was performed in 409 individuals, 386 of whom donated 717 blood samples before the onset of symptoms of RA (pre-patients). The median period of time predating the onset of RA was 7.4 years. A total of 1,305 population-based control subjects were also studied. Antibodies to 10 citrullinated peptides, fibrinogen 573 (Fib573), Fib591, Fib3652, Fib72, Fib74, -enolase (citrullinated -enolase peptide 1 [CEP-1]), triple-helical type II collagen peptide C1 (citC1III), filaggrin, vimentin 217 (Vim217), and Vim6075, were analyzed using a microarray system. Results The fluorescence intensity of antibodies against Fib3652, Fib74, CEP-1, citC1III, and filaggrin was significantly increased in pre-patients compared with controls (P < 0.001). The levels of the earliest-detectable antibodies (Fib591 and Vim6075) fluctuated over time, with only a slight increase after the onset of disease. The frequency of antibodies against Fib3652, CEP-1, and filaggrin increased gradually, reaching the highest levels before symptom onset. The frequency of a cluster of antibodies, citC1III, Fib573, and Fib74, increased only slightly before the onset of symptoms but increased prominently after disease onset. The odds ratio for the development of RA in individuals expressing both CEP-1 and Fib3652 antibodies (using data from samples obtained <3.35 years predating symptom onset) was 40.4 (95% confidence interval 19.882.3) compared with having either antibody alone. Conclusion Development of an immune response toward citrullinated peptides is initially restricted but expands with time to induce a more specific response, with levels, particularly those of antibodies against CEP-1, Fib3652, and filaggrin, increasing during the predating time period closer to the onset of symptoms.
5.
Dellavance, Alessandra, et al.
(författare)
Establishment of an international autoantibody reference standard for human anti-DFS70 antibodies : proof-of-concept study for a novel Megapool strategy by pooling individual specific sera
2019
Ingår i: Clinical Chemistry and Laboratory Medicine. - : WALTER DE GRUYTER GMBH. - 1434-6621 .- 1437-4331. ; 57:11, s. 1754-1763
Tidskriftsartikel (refereegranskat) abstract
Background: International autoantibody standards, traditionally based on material obtained from plasmapheresis of single subjects, represent individual immune response and may not comprehend the heterogeneity of the general population. The anti-DFS70 autoantibody yields a characteristic dense fine speckled (DFS) nuclear pattern on indirect immunofluorescence assay on HEp-2 cells (HEp-2 IFA) and speaks against autoimmunity. We propose a novel strategy for developing autoantibody reference standards, based on stepwise pooling of serum samples from hundreds of individuals with anti-DFS70 antibodies.Methods: Within a 2-year period, serum samples were selected from routine HEp-2 IFA according to the following criteria: DFS HEp-2 IFA pattern at titer >= 1:640; anti-DFS70 reactivity in three analyte-specific tests (Western blot [WB], enzyme-linked immunosorbent assay [ELISA] and chemiluminescent immunoassay [CLIA]). Aliquots of individual samples were combined into progressively larger pools with stepwise validation of intermediary pools as for individual samples. Validated intermediary pools were merged into a final pool for lyophilization.Results: A total of 741 validated samples yielded a 750 mL final pool that was lyophilized into thousands of 200 mu L-aliquots. Reconstituted aliquots yielded the expected anti-DFS70 reactivity in ELISA, CLIA and WB, as well as high-titer DFS HEp-2 IFA pattern. The appropriate antiDFS70 reactivity of the lyophilized pool was confirmed by seven international expert centers, using HEp-2 IFA, ELISA, WB and immunoprecipitation.Conclusions: This proof-of-concept study provides an innovative and efficient strategy to build serum reference standards for autoantibody testing. The anti-DFS70 standard will integrate the panel of standards of Autoantibody Standardization Committee (ASC, www.autoab.org ), contributing to education for proper assay validation and interpretation of the DFS pattern and other HEp-2 IFA patterns.
6.
Elbagir, Sahwa, et al.
(författare)
Elevated IgA antiphospholipid antibodies in healthy pregnant women in Sudan but not Sweden, without corresponding increase in IgA anti-β2 glycoprotein I domain 1 antibodies
2020
Ingår i: Lupus. - : SAGE Publications. - 0961-2033 .- 1477-0962. ; 29:5, s. 463-473
Tidskriftsartikel (refereegranskat) abstract
Objective: The role of antiphospholipid antibodies (aPL) during apparently normal pregnancy is still unclear. IgA aPL are prevalent in populations of African origin. Our aim was to measure all isotypes of anticardiolipin (anti-CL) and anti–β2 glycoprotein I (anti-β2GPI) in healthy pregnant and non-pregnant women of different ethnicities.Methods: Healthy Sudanese pregnant women (n = 165; 53 sampled shortly after delivery), 96 age-matched Sudanese female controls and 42 healthy pregnant and 249 non-pregnant Swedish women were included. IgA/G/M anti-CL and anti-β2GPI were tested at one time point only with two independent assays in Sudanese and serially in pregnant Swedes. IgA anti-β2GPI domain 1 and as controls IgA/G/M rheumatoid factor (RF), IgG anti–cyclic citrullinated peptide 2 (anti-CCP2) and anti–thyroid peroxidase (anti-TPO) were investigated in Sudanese females.Results: Pregnant Sudanese women had significantly higher median levels of IgA anti-CL, IgA anti-β2GPI (p < 0.0001 for both antibodies using two assays) and IgM anti-β2GPI (both assays; p < 0.0001 and 0.008) compared with non-pregnant Sudanese. IgA anti-CL and anti-β2GPI occurrence was increased among Sudanese pregnant women compared with national controls. No corresponding increase during pregnancy was found for IgA anti-β2GPI domain 1 antibodies. Both IgG anti-CL and IgG control autoantibodies decreased during and directly after pregnancy among Sudanese. Serially followed Swedish women showed no changes in IgA aPL, whereas IgG/M anti-CL decreased.Conclusions: IgA aPL are increased in Sudanese but not in Swedish women, without corresponding increase in IgA domain 1. Whether due to ethnicity and/or environmental influences the occurrence of IgA aPL during Sudanese pregnancies, and its clinical significance, is yet to be determined.
7.
ElShafie, Amir Ibrahim, et al.
(författare)
Cystatin C as a marker of immune complex-associated renal impairment in a sudanese population with visceral leishmaniasis
2006
Ingår i: American Journal of Tropical Medicine and Hygiene. - 0002-9637 .- 1476-1645. ; 75:5, s. 864-868
Tidskriftsartikel (refereegranskat) abstract
Renal function was studied in visceral leishmaniasis (VL) and post-kala-azar dermal leishmaniasis (PKDL) by means of the specific marker cystatin C and related to circulating immune complexes and cytokine production. Forty patients with VL (23 with sub-acute disease and 17 with acute disease), 17 patients with PKDL, and 22 healthy controls were included. Cystatin C, but not creatinine, was significantly raised in VL (P = 0.004). The highest levels of cystatin C were found in those with acute disease (P < 0.0001). In VL, cystatin C levels were positively correlated to circulating immune complexes and production of granulocyte-macrophage colony stimulating factor (GM-CSF), but negatively correlated to aspartate aminotransferase and lactate dehydrogenase. We conclude that cystatin C is a superior marker of glomerular function in leishmaniasis and that immune complex deposition and GM-CSF are two functions that most likely are causally involved in the mechanisms leading to glomerular dysfunction in leishmaniasis.
8.
Eriksson, Daniel, et al.
(författare)
Cytokine Autoantibody Screening in the Swedish Addison Registry Identifies Patients With Undiagnosed APS1
2018
Ingår i: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 1945-7197 .- 0021-972X. ; 103:1, s. 179-186
Tidskriftsartikel (refereegranskat) abstract
Context: Autoimmune polyendocrine syndrome type 1 (APS1) is a monogenic disorder that features autoimmune Addison disease as a major component. Although APS1 accounts for only a small fraction of all patients with Addison disease, early identification of these individuals is vital to prevent the potentially lethal complications of APS1.Objective: To determine whether available serological and genetic markers are valuable screening tools for the identification of APS1 among patients diagnosed with Addison disease.Design: We systematically screened 677 patients with Addison disease enrolled in the Swedish Addison Registry for autoantibodies against interleukin-22 and interferon-α4. Autoantibody-positive patients were investigated for clinical manifestations of APS1, additional APS1-specific autoantibodies, and DNA sequence and copy number variations of AIRE.Results: In total, 17 patients (2.5%) displayed autoantibodies against interleukin-22 and/or interferon-α4, of which nine were known APS1 cases. Four patients previously undiagnosed with APS1 fulfilled clinical, genetic, and serological criteria. Hence, we identified four patients with undiagnosed APS1 with this screening procedure.Conclusion: We propose that patients with Addison disease should be routinely screened for cytokine autoantibodies. Clinical or serological support for APS1 should warrant DNA sequencing and copy number analysis of AIRE to enable early diagnosis and prevention of lethal complications.
9.
Falorni, Alberto, et al.
(författare)
Determination of 21-hydroxylase autoantibodies: inter-laboratory concordance in the Euradrenal International Serum Exchange Program
2015
Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 53:11, s. 1761-1770
Tidskriftsartikel (refereegranskat) abstract
Background: 21-Hydroxylase autoantibodies (21OHAb) are markers of an adrenal autoimmune process that identifies individuals with autoimmune Addison's disease (AAD). Quality and inter-laboratory agreement of various 21OHAb tests are incompletely known. The objective of the study was to determine inter-laboratory concordance for 21OHAb determinations. Methods: Sixty-nine sera from 51 patients with AAD and 51 sera from 51 healthy subjects were blindly coded by a randomization center and distributed to 14 laboratories that determined 21OHAb, either by an "in-house" assay (n=9) using in vitro-translated S-35-21OH or luciferase-labeled 21OH or a commercial kit with I-125-21OH (n=5). Main outcome measures were diagnostic accuracy of each participating laboratory and inter-laboratory agreement of 21OHAb assays. Results: Intra-assay coefficient of variation ranged from 2.6% to 5.3% for laboratories using the commercial kit and from 5.1% to 23% for laboratories using "in-house" assays. Diagnostic accuracy, expressed as area under ROC curve (AUC), varied from 0.625 to 0.947 with the commercial kit and from 0.562 to 0.978 with "in-house" methods. Cohen's. of inter-rater agreement was 0.603 among all 14 laboratories, 0.691 among "in-house" laboratories, and 0.502 among commercial kit users. Optimized cutoff levels, calculated on the basis of AUCs, increased the diagnostic accuracy of every laboratory (AUC >0.9 for 11/14 laboratories) and increased the Cohen's. of inter-rater agreement. Discrepancies in quantitation of 21OHAb levels among different laboratories increased with increasing autoantibody levels. Conclusions: The quality of 21OHAb analytical procedures is mainly influenced by selection of cutoff value and correct handling of assay materials. A standardization program is needed to identify common standard sera and common measuring units.
10.
Frodlund, Martina, et al.
(författare)
Immunoglobulin A anti-phospholipid antibodies in Swedish cases of systemic lupus erythematosus : associations with disease phenotypes, vascular events and damage accrual
2018
Ingår i: Clinical and Experimental Immunology. - : WILEY. - 0009-9104 .- 1365-2249. ; 194:1, s. 27-38
Tidskriftsartikel (refereegranskat) abstract
Immunoglobulin (Ig) G- and IgM-class anti-cardiolipin antibodies (aCL) and lupus anti-coagulant (LA) are included in the 1997 update of the American College of Rheumatology (ACR-97) systemic lupus erythematosus (SLE) criteria. Despite limited evidence, IgA-aCL and IgA anti-(2)-glycoprotein-I (anti-(2)GPI) were included in the 2012 Systemic Lupus International Collaborating Clinics criteria. The present study aimed to evaluate IgG-/IgA-/IgM-aCL and anti-(2)GPI occurrence in relation to disease phenotype, smoking habits, pharmacotherapy, anti-phospholipid syndrome (APS) and organ damage among 526 Swedish SLE patients meeting ACR-97. Patients with rheumatoid arthritis (n=100), primary Sjogren's syndrome (n=50) and blood donors (n=507) served as controls. Anti-phospholipid antibodies (aPL) were analysed by fluoroenzyme-immunoassays detecting aCL/anti-(2)GPI. Seventy-six (14%) SLE cases fulfilled the Sydney APS-criteria, and 1 aCL/anti-(2)GPI isotype (IgG/IgA/IgM) occurred in 138 SLE patients (26%). Forty-five (9%) of the SLE cases had IgA-aCL, 20 of whom (4%) lacked IgG-/IgM-aCL. Seventy-four (14%) tested positive for IgA anti-(2)GPI, 34 (6%) being seronegative regarding IgG/IgM anti-(2)GPI. Six (1%) had APS manifestations but were seropositive regarding IgA-aCL and/or IgA anti-(2)GPI in the absence of IgG/IgM-aPL and LA. Positive LA and IgG-aPL tests were associated with most APS-related events and organ damage. Exclusive IgA anti-(2)GPI occurrence associated inversely with Caucasian ethnicity [odds ratio (OR)=021, 95% confidence interval (CI)=006-072) and photosensitivity (OR=019, 95% CI=005-072). Nephritis, smoking, LA-positivity and statin/corticosteroid-medication associated strongly with organ damage, whereas hydroxychloroquine-medication was protective. In conclusion, IgA-aPL is not rare in SLE (16%) and IgA-aPL analysis may have additional value among SLE cases with suspected APS testing negative for other isotypes of aPL and LA.
