<p>Induction of collagen-induced arthritis (CIA), an animal model for human rheumatoid arthritis, is dependent on anti-collagen type II (CII) antibodies. The effector mechanism by which autoantibodies contribute to inflammatory reactions in autoimmune diseases is not well understood. In this thesis I have studied the effector pathways used by IgG anti-CII antibodies to initiate arthritis, namely the IgG Fc receptors (FcγRs) and the complement system. We have found that FcγRIII is crucial for development of CIA, as CII-immunized mice lacking this receptor do not develop arthritis and IgG1 and IgG2b anti-CII antibodies require FcγRIII to trigger arthritis when transferred to naïve mice. The antibody-mediated arthritis was further enhanced in mice deficient in the inhibitory FcγRIIB, indicating that FcγRIIB regulates the activation of FcγRIII. Furthermore, we demonstrate that FcγRIII exist as three distinct haplotypes in mice, FcγRIII:H, FcγRIII:V and FcγRIII:T. Mice expressing the FcγRIII:H haplotype are more susceptible to CIA than mice expressing the FcγRIII:V haplotype, indicating that certain FcγRIII haplotype predisposes for CIA. We also show that the most likely FcγRIII-expressing effector cell in CIA is the macrophage, since FcγRIII-expressing macrophages exclusively can induce arthritis in FcγRIII-deficient mice challenged for CIA.</p><p>The complement system was also investigated in development of CIA. We found that this effector pathway is also necessary for onset of arthritis, as CIA was inhibited by treatment with anti-complement factor 5 (C5) antibodies. C5-deficient mice could neither develop CIA unless provided with C5-containing sera. </p><p>Taken together, the work presented in this thesis indicates that FcγRs and the complement system are crucial for the induction of experimental arthritis. These findings are important for understanding the mechanisms behind rheumatoid arthritis and blocking of these effector pathways may in the future be used as treatment of rheumatoid arthritis. </p>

The T cell function of a proliferation inducing ligand (APRIL or TNFSF13) remains unclear. By comparing APRIL-/- mice with wild type (WT) mice, we have investigated the roles of APRIL in Th1, Th2 and Th17 responses. With regard to APRIL in Th1 responses, cultured APRIL-/- CD4+ T cells showed increased IFN-gamma production under non-polarizing, but not under Th1 polarizing, conditions. No difference in antigen-specific IgG2a levels existed between APRIL-/- and WT mice immunized with ovalbumin (OVA) and complete Freund's adjuvant (CFA) which induces Th1 polarization. Our data indicate that APRIL represses Th1 responses only under non-polarizing conditions. As for APRIL in Th2 responses, cultured APRIL-/- CD4+ T cells exhibited enhanced Th2 cytokine production under non-polarizing conditions, and augmented IL-13 production under Th2 polarizing conditions. Upon immunization with OVA and aluminum potassium sulfate (alum) which induces Th2 polarization, APRIL-/- mice responded with an increased antigen-specific IgG1 response. In the OVA-induced allergic lung inflammation model which is mediated by Th2 responses, APRIL-/- mice had significantly aggravated allergic lung inflammation. Accordingly, a decoy receptor-Ig fusion protein, TACI-Ig, treatment to block APRIL in WT mice enhanced allergic lung inflammation. In agreement with the role of APRIL in CD4+ T cells, the transfer of APRIL sufficient, OVA-specific, TCR transgenic CD4+ T (OT-II) cells to APRIL-/- mice restored the suppressive effect of APRIL on allergic lung inflammation. Mechanistically, the expression of c-maf, the IL-4 gene transcription factor, was markedly enhanced in APRIL-/- CD4+ T cells under non-polarizing and Th2 polarizing conditions. Our data suggest that APRIL inhibits Th2 responses and allergic lung inflammation by suppressing IL-4 production in CD4+ T cells via diminished c-maf expression, and by suppressing IL-13 production in CD4+ T cells via an IL-4 independent, IL-13 specific pathway. Regarding APRIL in Th17 responses, the incidence of Th17-mediated collagen-induced arthritis (CIA) in APRIL-/- mice was reduced, in parallel with diminished levels of antigen-specific IgG2a autoantibody and IL-17 production. Our data indicate that APRIL promotes IL-17 production, and that APRIL-triggered signals contribute to arthritis. Our data clearly show that APRIL is important in T cell immunity, inhibitory in Th2 responses and costimulatory in Th17 responses.

The human being and other animals contain immensely complex biochemical processes that govern their function on a cellular level. It is estimated that several thousand small molecules (metabolites) are produced by various biochemical pathways in humans. Pathological processes can introduce perturbations in these biochemical pathways which can lead to changes in the amounts of some metabolites.Developments in analytical chemistry have made it possible measure a large number metabolites in a single blood sample, which gives a metabolic profile. In this thesis I have worked on establishing and understanding metabolic profiles from patients with rheumatoid arthritis (RA) and from animal models of the autoimmune diseases diabetes mellitus type 1 (T1D) and RA.Using multivariate statistical methods it is possible to identify differences between metabolic profiles of different groups. As an example we identified differences between patients with RA and healthy volunteers. This can be used to elucidate the biochemical processes that are active in a given pathological condition.Metabolite concentrations are affected by a many other things than the presence or absence of a disease. Both genomic and environmental factors are known to influence metabolic profiles. A main focus of my work has therefore been on finding strategies for ensuring that the results obtained when comparing metabolic profiles were valid and relevant. This strategy has included repetition of experiments and repeated measurement of individuals’ metabolic profiles in order to understand the sources of variation.Finding the most stable and reproducible metabolic effects has allowed us to better understand the biochemical processes seen in the metabolic profiles. This makes it possible to relate the metabolic profile differences to pathological processes and to genes and proteins involved in these.The hope is that metabolic profiling in the future can be an important tool for finding biomarkers useful for disease diagnosis, for identifying new targets for drug design and for mapping functional changes of genomic mutations. This has the potential to revolutionize our understanding of disease pathology and thus improving health care.

The existence of immune self-tolerance allows the immune system to mount responses against infectious agents, but not against self-molecular constitutes. Although self-tolerance is a robust phenomenon, in some individuals as well as in experimental models, the self-tolerance breaks down and as a result, a self-destructive autoimmune disease emerges. The underlying mechanisms for the development of autoimmune diseases are not known, but genetic, environmental and immunological factors are suggested to be involved. In this thesis, we used murine mercury-induced autoimmunity to test this suggestion. In susceptible mice mercuric chloride induces a systemic autoimmune disease characterized by increased serum levels of IgG1 and IgE, production of anti-nucleolar autoantibodies (ANolA) and formation of renal IgG deposits. In contrast, in resistant DBA/2 (H-2d) mice, none of these characteristics develop after exposure to mercury. By crossing and backcrossing mercury-resistant DBA/2 mice to mercury susceptible strains, we found that the resistance was inherited as a dominant trait in F1 hybrids and that one gene or a cluster of genes located in the H-2 loci determined the resistance to ANolA production, whereas resistance to the other characteristics was found to be controlled by two or three non-H-2 genes. We further put forward the “cryptic peptide hypothesis” to investigate whether mercury and another xenobiotic metal use similar pathway(s) to induce the H-2 linked production of ANolA. We found that while mercury stimulated ANolA synthesis in all H-2 susceptible (H-2s, H-2q and H-2f) mouse strains, silver induced only ANolA responses in H-2s and H-2q mice, but not in H-2f mice. Further studies showed that the resistance to silver-induced ANolA production in H-2f mice was inherited as a dominant trait. We next tested the proposition that mercury induces more adverse immunological effects in mouse strains, which are genetically prone to develop autoimmune diseases, using tight-skin 1 mice, an animal model for human Scleroderma. It was found that in this strain, mercury induced a strong immune activation with autoimmune characteristics, but did not accelerate the development of dermal fibrosis, a characteristic in Tsk/1 mice. Finally we addressed the Th1/Th2 cross-regulation paradigm by examining if a Th1-type of response could interact with a Th2-type of response if simultaneous induced in susceptible mice. Our findings demonstrated that mercury-induced autoimmunity (Th2-type) and collagen-induced arthritis (CIA) (Th1-type) can interact in a synergistic, antagonistic or additive fashion, depending on at which stage of CIA mercury is administered.

Induction of collagen-induced arthritis (CIA), an animal model for human rheumatoid arthritis, is dependent on anti-collagen type II (CII) antibodies. The effector mechanism by which autoantibodies contribute to inflammatory reactions in autoimmune diseases is not well understood. In this thesis I have studied the effector pathways used by IgG anti-CII antibodies to initiate arthritis, namely the IgG Fc receptors (FcγRs) and the complement system. We have found that FcγRIII is crucial for development of CIA, as CII-immunized mice lacking this receptor do not develop arthritis and IgG1 and IgG2b anti-CII antibodies require FcγRIII to trigger arthritis when transferred to naïve mice. The antibody-mediated arthritis was further enhanced in mice deficient in the inhibitory FcγRIIB, indicating that FcγRIIB regulates the activation of FcγRIII. Furthermore, we demonstrate that FcγRIII exist as three distinct haplotypes in mice, FcγRIII:H, FcγRIII:V and FcγRIII:T. Mice expressing the FcγRIII:H haplotype are more susceptible to CIA than mice expressing the FcγRIII:V haplotype, indicating that certain FcγRIII haplotype predisposes for CIA. We also show that the most likely FcγRIII-expressing effector cell in CIA is the macrophage, since FcγRIII-expressing macrophages exclusively can induce arthritis in FcγRIII-deficient mice challenged for CIA. The complement system was also investigated in development of CIA. We found that this effector pathway is also necessary for onset of arthritis, as CIA was inhibited by treatment with anti-complement factor 5 (C5) antibodies. C5-deficient mice could neither develop CIA unless provided with C5-containing sera. Taken together, the work presented in this thesis indicates that FcγRs and the complement system are crucial for the induction of experimental arthritis. These findings are important for understanding the mechanisms behind rheumatoid arthritis and blocking of these effector pathways may in the future be used as treatment of rheumatoid arthritis.

In autoimmune diseases such as rheumatoid arthritis (RA), self-reactive antibodies are present at high levels, which contributes to disease pathogenesis. The antibodies mediate their effect predominantly by binding to Fc gamma receptors (FcγR) on various leukocytes, such as monocytes, macrophages and mast cells, where FcγR ligation leads to cell activation. In this thesis the role of FcγR in RA was investigated. We could, for the first time, demonstrate an increased expression of the inhibitory FcγRIIb in RA synovial tissue, while this receptor as well as FcγRI were almost absent in healthy synovial tissue. The enhanced FcγRI expression in RA synovia was reduced by one intraarticular injection of glucocorticoids, indicating that FcγRI participates in the joint inflammation. Interestingly, RA patients with an ongoing joint inflammation exhibited blood monocytes with immune compromised features, such as decreased FcγR binding of IgG1-IC and reduced TNF production. These effects were associated with high levels of auto-antibodies in the patients, implying that the monocyte FcγR are saturated with IgG. In order to investigate whether soluble FcγR could be used as a therapy in arthritis, we injected human soluble FcγR into mice with collagen-induced arthritis (CIA). The soluble FcγR reduced the levels of pathogenic IgG anti-collagen type II (CII) antibodies, arthritis severity and pro-inflammatory cytokines. Thus, suggesting that soluble FcγR may represent a novel therapeutic agent in RA. We also studied the disease-aggravating role of mast cells in arthritis by investigating mouse mast cell protease-4 (mMCP-4) in CIA. We found that mMCP-4 deficient mice displayed a reduced IgG anti-CII response and reduced arthritis severity. This indicates a role for mMCP-4 in adaptive immunity. In conclusion, these data demonstrate that IgG occupancy of FcγR and mast cell secretion of mMCP-4 play vital roles in the development of autoimmune arthritis.

Objective to systematically review randomized trials that compared methotrexate (MTX) monotherapy to MTX in combination with other non-biologic disease-modifying anti-rheumatic Drugs (DMARD) and to compare the performances of PubMed versus MEDLINE (Ovid®) and EMBASE. Methods We performed a systematic review of randomized trials comparing MTX alone and MTX in combination with other non-biologic DMARDs. Heterogeneity was investigated and explored. The performances of Pubmed and MEDLINE were evaluated. The EMBASE unique trials were identified and investigated. Results A total of 19 trials were included and grouped by the type of patients randomized. Trials in DMARD naive patients showed no significant advantage of the MTX combination versus monotherapy. The recall was 85% vs. 90% for Ovid and PubMed, respectively, while the precision and number-needed-to read of Ovid and Pubmed were comparable. Only 23% of trials were EMBASE unique trials Conclusions In DMARD naive patients, the balance of efficacy/toxicity favours MTX monotherapy.

Objective to systematically review randomized trials that compared methotrexate (MTX) monotherapy to MTX in combination with other non-biologic disease-modifying anti-rheumatic Drugs (DMARD) and to compare the performances of PubMed versus MEDLINE (Ovid®) and EMBASE. Methods We performed a systematic review of randomized trials comparing MTX alone and MTX in combination with other non-biologic DMARDs. Heterogeneity was investigated and explored. The performances of Pubmed and MEDLINE were evaluated. The EMBASE unique trials were identified and investigated. Results A total of 19 trials were included and grouped by the type of patients randomized. Trials in DMARD naive patients showed no significant advantage of the MTX combination versus monotherapy. The recall was 85% vs. 90% for Ovid and PubMed, respectively, while the precision and number-needed-to read of Ovid and Pubmed were comparable. Only 23% of trials were EMBASE unique trials Conclusions In DMARD naive patients, the balance of efficacy/toxicity favours MTX monotherapy.

SAMMANFATTNING Hydroterapi har under en längre tid använts som behandlingsform, men det är brist på forskning inom området. Syftet med denna studie var att undersöka upplevelsen av hydroterapi hos personer med reumatisk sjukdom. En kvalitativ ansats anlades och enskilda semistrukturerade intervjuer användes. Deltagarna rekryterades genom bekvämlighetsurval via en kontakt på en reumatologklinik. Sex personer inkluderades: fem hade reumatoid artrit och en hade pelvospondylit. Resultatet tolkades med hjälp av en kvalitativ innehållsanalys, som visade på att deltagarna i denna studie var positivt inställda till hydroterapi. Deltagarna upplevde att hydroterapin ledde till minskad smärta, ökad rörlighet samt ett ökat välmående. Utöver de upplevda positiva effekterna återfanns även upplevda negativa effekter i form av träningsvärk och en ökad stelhet under sommaruppehållen. Det sociala samspel som uppstod i samband med hydroterapin upplevdes av de flesta deltagare ha haft positiv betydelse. Deltagarnas upplevelser kunde i diskussionen kopplas till operant och respondent inlärningsteori, där tänkbara konsekvenser och stimulin identifierades. Slutsatsen som drogs var att deltagarna upplevde hydroterapin som ett sätt att få tillbaka sin friska kropp genom att symtomen minskade. Då deltagarna upplevde att uppehåll orsakade försämring behövs hydroterapi som kontinuerlig behandlingsform för dem. Vidare forskning inom området bör fokuseras på enskilda patientgrupper samt inkludera ett större antal deltagare per patientgrupp. Nyckelord: hydroterapi, intervju, kvalitativ, pelvospondylit, reumatoid artrit.

La artritis reumatoide (AR) es la artropatía inflamatoria crónica más frecuente, afecta aproximadamente el 0.5% - 1% de la población general y causa una progresiva destrucción articular, discapacidad y disminución de la expectativa de vida. La etiología de la AR es desconocida y su patogenia solo parcialmente conocida al día de hoy. En los últimos años se han estudiado e identificado múltiples factores de riesgo para su desarrollo. Sabemos que intervienen factores genéticos y ambientales y que la interacción de ambos puede ser determinante en el desarrollo de la enfermedad. Entre los factores ambientales el tabaco ha sido ampliamente estudiado y actualmente se lo reconoce como el factor de riesgo no genético más importante para el desarrollo de AR, siendo este efecto particularmente importante en aquellos sujetos que presentan una susceptibilidad genética (presencia del epitopo reumatoide (ER)). Estudios más recientes ponen de manifiesto que el consumo de tabaco puede influir además en la expresión clínica de la enfermedad, determinar un curso evolutivo más grave y una mayor destrucción articular, aunque no todos los estudios son concordantes en estos últimos aspectos. El objetivo general de esta tesis fue analizar el efecto del consumo de tabaco en la expresión clínica y curso evolutivo de la artritis reumatoide en una cohorte de pacientes con artritis reumatoide de reciente comienzo. Para esto se llevó a cabo un estudio prospectivo en una cohorte de pacientes con artritis reumatoide de inicio (menos de dos años desde el inicio de los síntomas). En ellos se analizaron las características epidemiológicas, clínicas, serológicas y radiológicas basales y periódicamente, cada tres meses, hasta los dos años de evolución. Estas variables fueron comparadas entre aquellos pacientes fumadores y los no fumadores. Se observó que los pacientes con AR fumadores son con mayor frecuencia son portadores del epitopo reumatoide, lo que sugiere la existencia de una relación genético-ambiental en el desarrollo de la AR. En nuestra serie no hemos podido observar relación entre el consumo de tabaco y la presencia de ACPA. Desde el punto de vista de la expresión clínica de la AR, los pacientes fumadores presentaron un debut de su enfermedad más temprano que los no fumadores. La actividad clínica y biológica de la enfermedad y discapacidad que presentaron tanto al momento del debut de la AR como tras dos años de seguimiento fueron similares entre fumadores y no fumadores. El tabaco no parece influir en la expresión clínica de la enfermedad (a corto plazo). En cuanto a la destrucción articular, el tabaco demostró ser un factor predictor independiente de destrucción articular, junto con el sexo femenino y la presencia del ER. No obstante la magnitud de este efecto sería moderada. La prevalencia de ACPA en la población sana, tanto si son fumadores o no lo son, es del 1.9%. En grandes fumadores el consumo de tabaco no determina una mayor producción de ACPA. Sin embargo los grandes fumadores con EPOC sí tendrían una mayor predisposición a la producción de ACPA, aunque a títulos bajos. La implicación y relevancia clínica de los mismos debe ser aún estudiada en mayor profundidad.