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- Åhlin, Erik, 1980-
(författare)
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Functional Role of Immune Complexes in Rheumatic and Parasitic Diseases
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immune complexes (IC) have key pathological roles in both autoimmune and infectious diseases. In this thesis functional mechanisms behind IC-driven inflammation in rheumatic diseases and tropical infections have been studied, with special focus on the contribution of autoantibodies and cytokine-inducing properties of IC. In the autoimmune disease SLE, increased levels of IC-induced cytokines were associated with both increased classical complement activation and the occurrence of the autoantibodies anti-SSA and anti-SSB, both directed against RNA-associated antigens. In addition, complement activation and anti-SSA synergistically predisposed to higher levels of IC in sera. In the following study it was demonstrated that also other autoantibodies against RNA-associated autoantigens were more enriched than anti-dsDNA in SLE IC. Sudanese Visceral Leishmaniasis (VL) patients had elevated IC levels, and precipitated IC induced higher levels of GM-CSF, IL10, IL6 and IL1RA than control IC. Levels of IC were especially prominent in severely ill patients receiving antimony treatment, and a parallel association with IC induction of GM-CSF was demonstrated. Leishmania-infected patients were often rheumatoid factor (RF) positive and a substantial number displayed reactivity towards cyclic citrullinated peptide (CCP) antigens. Contrary to what was seen in Sudanese RA sera, the CCP reactivity was not restricted to citrulline but reacted equally well with arginine-containing control peptides. Levels of anti-CCP among VL patients were not due to cross-reactions with, or CCP-reactivity bound to IC. I have demonstrated that IC are associated with the presence of autoantibodies in both SLE and in Leishmania infection. In SLE, autoantibodies against RNA-associated antigens were more prone to form circulating IC than anti-dsDNA. In Leishmania infection false reactivity against the CCP-autoantigen correlated to IC levels although the IC themselves did not contain such reactivity. In both diseases higher IC levels were associated with a more active disease, and purified IC induced key cytokines in disease pathogeneses.
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| 2. |
- 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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| 3. |
- Rubér, Marie
(författare)
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Immunopathogenic aspects of resolving and progressing appendicitis
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Appendicitis is one of the most common diseases requiringemergency surgical intervention. There are several indications that the diagnosisappendicitis harbours two different entities, one progressing to gangrene and perforation(advanced) and one that resolves spontaneously (phlegmonous). An immunologically drivenpathogenesis in appendicitis has been suggested on the basis of an inverse relationshipbetween appendicitis and ulcerative colitis, a positive association with Crohn’s disease, anda decreased incidence during pregnancy, generating the hypothesis that theimmunopathogenesis in advanced appendicitis is characterized by a Th1 inflammatoryresponse. The aim of this thesis was to test this hypothesis and investigate the immuneresponse in advanced and phlegmonous appendicitis.Material and Methods: The immunologic response was investigated in appendicitis tissue and compared to the immunological response in peripheral blood, analysed by enzyme-linked immunospot assay (ELISPOT). The response pattern was also investigated in patients with an actual appendicitis in the peripheral plasma and peripheral serum before surgery, analysed with Luminex. The immunological response pattern was investigated in peripheral blood several months to years after an appendectomy using ELISPOT and enzyme-linked immunosorbent assay (ELISA).Results: The local immune response in the appendiceal tissue in appendicitis was similar to the response in peripheral blood. Patients with actual advanced appendicitis had increased levels of IL-6, CCL20, CCL2, TGF-β, IL-17, IFN-γ, IL-12p70, IL-10, IL-1ra, IL-4, MMP-8, MMP-9 and MPO compared with those with phlegmonous appendicitis. Sex, age or duration of symptoms could not explain the differences between the groups. Individuals with a history of advanced appendicitis had increased secretion of IFN-γ months to years after the appendectomy compared with individuals with a history of phlegmonous appendicitis.Conclusions: The local immune response in the appendiceal tissue is mirrored in the blood, which justifies the use of peripheral blood in studies on appendicitis. The immunological response pattern in peripheral blood suggests Th1/Th17- induced inflammation in advanced appendicitis that is present at an early stage. Individuals with a history of advanced appendicitis have stronger Th1 responses than individuals with a history of phlegmonous appendicitis. This may reflect constitutional differences between patients with different outcomes of appendicitis. The increased inflammatory response observed early in advanced appendicitis suggests a more violent inflammation and supports the hypothesis of different immune pathogeneses, where excessive induction of Th1/Th17 immunity and/or deficiencies in down-regulatory feedback mechanisms may explain the excessive inflammation in advanced appendicitis, where the inflammation eventuates in gangrene and perforation.
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