| 1. |
- Lundgren, Hanna, et al.
(författare)
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HLA-DR7 and HLA-DQ2 : Transgenic mouse strains tested as a model system for ximelagatran hepatotoxicity
- 2017
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Ingår i: PLOS ONE. - San Francisco, United States : Public Library of Science. - 1932-6203. ; 12:9
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Tidskriftsartikel (refereegranskat)abstract
- The oral thrombin inhibitor ximelagatran was withdrawn in the late clinical trial phase because it adversely affected the liver. In approximately 8% of treated patients, drug-induced liver injury (DILI) was expressed as transient alanine transaminase (ALT) elevations. No evidence of DILI had been revealed in the pre-clinical in vivo studies. A whole genome scan study performed on the clinical study material identified a strong genetic association between the major histocompatibility complex alleles for human leucocyte antigens (HLA) (HLA-DR7 and HLA-DQ2) and elevated ALT levels in treated patients. An immunemediated pathogenesis was suggested. Here, we evaluated whether HLA transgenic mice models could be used to investigate whether the expression of relevant HLA molecules was enough to reproduce the DILI effects in humans. In silico modelling performed in this study revealed association of both ximelagatran (pro-drug) and melagatran (active drug) to the antigen-presenting groove of the homology modelled HLA-DR7 molecule suggesting "altered repertoire" as a key initiating event driving development of DILI in humans. Transgenic mouse strains (tgms) expressing HLA of serotype HLA-DR7 (HLA-DRB1*0701, -DRA*0102), and HLA-DQ2 (HLA-DQB1*0202, -DQA1*0201) were created. These two lines were crossed with a human (h) CD4 transgenic line, generating the two tgms DR7xhCD4 and DQ2xhCD4. To investigate whether the DILI effects observed in humans could be reproduced in tgms, the mice were treated for 28 days with ximelagatran. Results revealed no signs of DILI when biomarkers for liver toxicity were measured and histopathology was evaluated. In the ximelagatran case, presence of relevant HLA-expression in a preclinical model did not fulfil the prerequisite for reproducing DILI observed in patients. Nonetheless, for the first time an HLA-transgenic mouse model has been investigated for use in HLA-associated DILI induced by a low molecular weight compound. This study shows that mimicking of genetic susceptibility, expressed as DILI-associated HLA-types in mice, is not sufficient for reproducing the complex pathogenesis leading to DILI in man.
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| 2. |
- Martinsson, Klara, et al.
(författare)
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Extramucosal Formation and Prognostic Value of Secretory Antibodies in Rheumatoid Arthritis
- 2022
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Ingår i: Arthritis & Rheumatology. - Hoboken, NJ, United States : John Wiley & Sons. - 2326-5191 .- 2326-5205. ; 74:5, s. 801-809
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Tidskriftsartikel (refereegranskat)abstract
- Objective To investigate levels and possible extramucosal formation of secretory Ig, including anti-citrullinated protein antibodies (ACPAs), in rheumatoid arthritis (RA). Methods Three patient groups were studied: 1) ACPA-positive patients with musculoskeletal pain without clinical arthritis, 2) patients with recent-onset RA, and 3) patients with established RA. In baseline serum samples (groups 1 and 2) and paired synovial fluid samples (group 3), we analyzed total secretory IgA, total secretory IgM, free secretory component (SC), and SC-containing ACPA. Extramucosal formation of SC-containing ACPA was investigated by preincubating RA sera and affinity-purified ACPA with recombinant free SC.Results Compared to healthy controls, serum levels of total secretory IgA and total secretory IgM were increased both in patients with early RA and at-risk patients (P < 0.05). Patients with early RA with elevated total secretory Ig had significantly higher disease activity during the 3-year follow-up period compared to those without increased levels. At-risk patients who developed arthritis during follow-up (39 of 82) had higher baseline total secretory IgA levels compared to those who did not (P = 0.041). In established RA, total secretory IgA and total secretory IgM levels were higher in serum than in synovial fluid (P < 0.0001), but SC-containing ACPAs adjusted for total secretory Ig concentration were higher in synovial fluid (P < 0.0001). Preincubation with recombinant free SC yielded increased SC-containing ACPA reactivity in sera as well as in affinity-purified IgA and IgM ACPA preparations.Conclusion Circulating secretory Ig are elevated before and at RA onset. In the presence of free SC, secretory Ig may form outside the mucosa, and SC-containing ACPAs are enriched in RA joints. These findings shed important new light on the mucosal connection in RA development.
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| 3. |
- Martinsson, Klara, 1977-
(författare)
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Fcγ-receptors in systemic autoimmune conditions : lessons from murine mercury-induced autoimmunity
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we investigated the role of activating (FcγRI, FcγRIII) and inhibitory (FcγRIIB) Fcγ-receptors on systemic autoimmunity using two mouse strains, DBA/1 (H-2q) and BALB/c mice (H-2d), susceptible to induction of autoimmunity by mercury (Hg).Fc-receptors for IgG (FcγR) link cellular and humoral immune responses, control the balance between activating and inhibitory immune responses and are important in the development of several autoimmune diseases. Mercury induces a T cell-dependent autoimmune condition, Hg-induced autoimmunity (HgIA) in genetically (H-2s,q,f,t2) susceptible mice characterized in its fullblown type by lymphoproliferation, hypergammaglobulinemia, systemic immune-complex (IC) deposits and antinucleolar antibodies (ANoA). All manifestations in HgIA are dependent on the presence of IFN-γ.Hg-treated BALB/c mice lacking activating FcγRs (FcγRI, FcγIII and FcεRI) showed significantly higher levels of both IgG1- and IgG2a-CIC whereas renal mesangial and vessel wall IC deposits were severely delayed and reduced/abolished, compared to mice without mutations (wild type, wt). Wt mice developed modest levels of IgG1- and IgG2a-CIC followed by a distinct formation of IC deposits in the renal glomerular mesangium, as well in renal and splenic vessel walls. Compared to wt mice, the mice lacking the inhibitory FcγRIIB showed similar titres of IC deposits in the renal mesangium, whereas vessel wall IC deposits were reduced.DBA/1 mice deficient for the FcRγ-chain (lack of the activating receptors FcγRI, FcγIII and FcεRI) or FcγRIII and treated with Hg showed a delayed and attenuated IgG1, IgG2a and IgG2b ANoA response compared to wt mice.Increasing the Hg dose or prolonging the treatment time could not override the attenuated ANoA response seen in FcγRIII mice. Female Hg-treated FcγRIIB mice showed a significant increase of IgG2b ANoA development compared to wt mice.The total serum IgG1 response due to treatment with Hg was attenuated in both BALB/c mice lacking the Fcγ-chain, and in DBA/1 mice lacking either the Fcγ- chain or specifically the FcγRIII compared to wt mice. This indicates that FcγRIII is the receptor important for the in HgIA characteristic serum IgG1 response. On the other hand, Hg-treated FcγRIIB deficient BALB/c and DBA/1 mice showed an increase of both serum IgG1 and IgE compared to wt mice.The cytokine profile in DBA/1 wt mice treated with Hg revealed a more marked Th1 profile compared to FcγRIII deficient mice. In contrast, the total Th2 and Th17 profile increased in both wt and FcγRIII deficient mice. However, during Hg treatment IL-21 mRNA expression was significantly reduced in FcγRIII deficient mice compared with wt mice. The increased Th1 profile in the wt mice could not be attributed to an increase of IFN-γ secretion from the major IFN-γ cell source, NK cells.We conclude that FcγRIII are important for the formation of IC deposits as shown by the delayed and reduced formation of IC deposits and the high levels of CIC in mice lacking FcγRIII. The expression of FcγRIII is also of importance for the rapidity and final strength of the ANoA response probably due to a reduced expression of Th1 cytokines and inflammatory factors. The ANoA response is modestly counter-regulated by FcγRIIB. The increase of serum IgG1 in HgIA is dependent on FcγRIII which is likely to be mediated by the low expression of IL- 21 in mice deficient for FcγRIII. In contrast, lack of FcγRIIB increases both the serum IgG1 and IgE response.
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| 4. |
- Roos Ljungberg, Karin, 1988-
(författare)
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Secretory Autoantibodies in Rheumatoid Arthritis
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Rheumatoid arthritis (RA) is a chronic autoimmune inflammatory disease in which autoantibodies, such as anti-citrullinated protein antibodies (ACPA), can be detected in the serum of patients. Autoantibodies may appear in the circulation years before clinical signs of joint inflammation occur, indicating that early immunological pathogenetic steps take place outside of the joints. Although many of these mechanisms are currently unknown, the initial events leading up to ACPA production are thought to occur at mucosal surfaces. In this thesis, mucosa-associated secretory ACPA are investigated in the circulation and in local mucosal secretions to: (i) improve the understanding of the mucosal connection in RA; and (ii) investigate whether these antibodies can improve diagnostics and prognostics in early RA. We identified circulating secretory component containing (SC) ACPA in a subpopulation of patients (both early and established RA) and at-risk patients, with a prevalence of 16%-21%. In addition, SC ACPA was detected in bronchoalveolar lavage fluid (BALF) and IgA ACPA in saliva, indicating local production in the lungs and in the oral cavity. In at-risk patients who were positive for IgG ACPA, we found that the levels of circulating SC ACPA at inclusion predicted arthritis development. Circulating SC ACPA was associated with higher disease activity, including increased levels of inflammatory markers, in patients with early RA. Levels of circulating SC ACPA were associated with high-resolution computed tomography (HRCT) findings (parenchymal lung abnormalities and bronchiectasis) and smoking, but not with risk genes (shared epitope). We confirmed the presence of salivary ACPA and identified a novel association with increased disease activity and functional disability. In summary, SC ACPA is present in the sera of patients with RA who manifest different phases of the disease, and we found associations with arthritis onset, smoking, systemic inflammation, and lung abnormalities. SC ACPA is also detectable in mucosal secretions from the lungs and the oral cavity. These findings suggest that mucosal ACPA production may be an important factor in RA development and progression, and that serum SC ACPA should be further evaluated as a prognostic marker for disease onset among at-risk individuals.
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| 5. |
- Weitoft, Tomas, et al.
(författare)
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Exhaled Nitric Oxide Reflects the Immune Reactions of the Airways in Early Rheumatoid Arthritis
- 2024
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Ingår i: Biomedicines. - : MDPI. - 2227-9059. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Patients with rheumatoid arthritis (RA) have altered levels of exhaled nitric oxide (NO) compared with healthy controls. Here, we investigated whether the clinical features of and immunological factors in RA pathogenesis could be linked to the NO lung dynamics in early disease. A total of 44 patients with early RA and anti-citrullinated peptide antibodies (ACPAs), specified as cyclic citrullinated peptide 2 (CCP2), were included. Their exhaled NO levels were measured, and the alveolar concentration, the airway compartment diffusing capacity and the airway wall concentration of NO were estimated using the Högman–Meriläinen algorithm. The disease activity was measured using the Disease Activity Score for 28 joints. Serum samples were analysed for anti-CCP2, rheumatoid factor, free secretory component, secretory component containing ACPAs, antibodies against Porphyromonas gingivalis (Rgp) and total levels of IgA, IgA1 and IgA2. Significant negative correlations were found between the airway wall concentration of NO and the number of swollen joints (Rho −0.48, p = 0.004), between the airway wall concentration of NO and IgA rheumatoid factor (Rho −0.41, p = 0.017), between the alveolar concentration and free secretory component (Rho −0.35, p = 0.023) and between the alveolar concentration and C-reactive protein (Rho −0.36, p = 0.016), but none were found for anti-CCP2, IgM rheumatoid factor or the anti-Rgp levels. In conclusion, altered NO levels, particularly its production in the airway walls, may have a role in the pathogenesis of ACPA-positive RA.
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