Suppression of Inflammatory Arthritis by Human Gut-Derived Prevotella histicola in Humanized Mice.

OBJECTIVE: The gut microbiome regulates host immune homeostasis. Rheumatoid arthritis (RA) is associated with intestinal dysbiosis. This study was undertaken to test the ability of a human gut-derived commensal to modulate immune response and treat arthritis in a humanized mouse model. METHODS: We isolated a commensal bacterium, Prevotella histicola, that is native to the human gut and has systemic immune effects when administered enterally. Arthritis-susceptible HLA-DQ8 mice were immunized with type II collagen and treated with P histicola. Disease incidence, onset, and severity were monitored. Changes in gut epithelial proteins and immune response as well as systemic cellular and humoral immune responses were studied in treated mice. RESULTS: When treated with P histicola in prophylactic or therapeutic protocols, DQ8 mice exhibited significantly decreased incidence and severity of arthritis compared to controls. The microbial mucosal modulation of arthritis was dependent on regulation by CD103+ dendritic cells and myeloid suppressors (CD11b+Gr-1+ cells) and by generation of Treg cells (CD4+CD25+FoxP3+) in the gut, resulting in suppression of antigen-specific Th17 responses and increased transcription of interleukin-10. Treatment with P histicola led to reduced intestinal permeability by increasing expression of enzymes that produce antimicrobial peptides as well as tight junction proteins (zonula occludens 1 and occludin). However, the innate immune response via Toll-like receptor 4 (TLR-4) and TLR-9 was not affected in treated mice. CONCLUSION: Our results demonstrate that enteral exposure to P histicola suppresses arthritis via mucosal regulation. P histicola is a unique commensal that can be explored as a novel therapy for RA and may have few or no side effects.

Idiopathic retroperitoneal fibrosis: a retrospective review of clinical presentation, treatment, and outcomes.

OBJECTIVE: To describe the clinical manifestations, laboratory results, imaging findings, and treatments in patients with idiopathic retroperitoneal fibrosis (IRF) seen at Mayo Clinic in Rochester, MN. PATIENTS AND METHODS: In this retrospective study, we used International Classification of Diseases, Ninth Revision codes to identify all patients evaluated for IRF between January 1, 1996, and December 31, 2006, at Mayo Clinic in Rochester, MN. Medical records were reviewed, and clinical information was abstracted. Idiopathic retroperitoneal fibrosis was diagnosed on the basis of compatible imaging findings. Patients were followed up until their last visit at Mayo Clinic, death, or December 31, 2008, whichever came first. RESULTS: Of the 185 patients identified as having IRF, 113 (61%) were men and 72 (39%) were women. Mean ± SD age at diagnosis was 57.6 ± 11.8 years. Biopsy specimens were obtained in 142 cases (77%). The most common presenting symptoms were back pain (38%) and abdominal pain (40%). Baseline erythrocyte sedimentation rate and/or C-reactive protein levels were elevated in 88 (58%) of the 151 patients tested. The median creatinine level at diagnosis was 1.3 mg/dL (interquartile range, 1.1-2.1 mg/dL). Fifteen patients (8%) were treated with ureteral procedures only, 58 patients (31%) with medications only, and 105 patients (57%) with a combination of medical and surgical therapies. Seven patients (4%) were not treated. Corticosteroids were initiated in 116 patients (63%), and tamoxifen was used in 120 patients (65%). Follow-up was available for 151 patients (82%). Creatinine levels were normal at last visit in 102 (68%) of the 151 patients with follow-up. No patient developed end-stage renal disease. Relapses occurred in 18 (12%) of the 151 patients. Eleven patients died. CONCLUSION: In this cohort, outcomes such as end-stage renal disease or death from renal failure were not observed. Relapses may occur, and patients with IRF warrant long-term follow-up.

B cells are important as antigen presenting cells for induction of MHC-restricted arthritis in transgenic mice.

Rheumatoid arthritis and its animal model, collagen-induced arthritis, are known as a T and B cell dependent disease. To analyze the role of B cells in arthritis, we generated B cell deficient (microMT) mice carrying HLA-DQ8 as transgene, Abetao.DQ8.micromt mice. HLA-DQ8 transgenic mice (Abetao.DQ8) are susceptible to collagen induced arthritis, an animal model for inflammatory arthritis. Deletion of IgM gene led to the absence of B cells while T cells were comparable to Abetao.DQ8 mice. Arthritis and autoantibodies was completely abrogated in B cell deficient DQ8 mice. T cell response and proinflammatory cytokine production in response to type II collagen and its derived peptides in vitro was significantly decreased despite an increased number of Mac-1 positive cells in DQ8.micromt mice compared to DQ8 mice suggesting B cells could be important for antigen presentation as well. In vitro substitution of B cells from wild type mice restored the response in DQ8.micromt mice. B cells could also present CII-derived peptides to antigen-specific DQ8-restricted hybridomas reinforcing the role of B cells in presentation of antigens to T cells. The data suggest that B cells can be involved in pathogenesis of arthritis by producing autoantibodies and antigen presentation.

New humanized HLA-DR4-transgenic mice that mimic the sex bias of rheumatoid arthritis.

OBJECTIVE: To generate a mouse model that can mimic human rheumatoid arthritis (RA). A major difference between RA in humans and collagen-induced arthritis (CIA) in mice is the lack of sex bias and autoantibodies in the animal model. We used DRB1*0401-transgenic mice to understand the role of DR4 in susceptibility and sex bias in RA. METHODS: A transgenic mouse was generated that lacked all endogenous mouse class II genes (AE(o)) and expressed the RA susceptibility allele HLA-DRB1*0401. These transgenic mice were tested for incidence, severity, and sex distribution of CIA. RESULTS: DRB1*0401.AE(o) mice developed CIA predominantly in females and produced rheumatoid factors, similar to the features of human RA. Another feature similar to human RA is the expression of class II molecules on antigen-presenting cells as well as T cells. Activated and sorted CD4(+) T cells can present DR4-restricted type II collagen (CII)-derived peptide in vitro, but cannot process the antigen. This suggests a role for these cells in epitope presentation locally in joints, which affects disease severity. After challenge with CII, female mice had higher cellularity and increased T cell proliferation and produced higher levels of proinflammatory cytokines than did the male mice. CONCLUSION: DR4.AE(o) mice expressed HLA similar to humans and displayed increased arthritis susceptibility in females, thus mimicking RA in humans. This model may be valuable for studying sex differences observed in humans and for understanding why autoimmunity is increased in women. These mice may also be useful for developing future therapeutic strategies.

Echocardiographically guided pericardiocentesis for treatment of clinically significant pericardial effusion in rheumatoid arthritis.

OBJECTIVE: To assess the safety and efficacy of echocardiographically guided pericardiocentesis for patients with rheumatoid arthritis (RA) and hemodynamically significant pericardial effusion. METHODS: We identified 16 patients with RA who underwent 18 echocardiographically guided pericardiocentesis procedures at our institution over a 20-year period. Clinical and laboratory characteristics of the patients, response to treatment, complications, and need for future pericardial surgery were abstracted from the echocardiography database. RESULTS: Ten patients were men and 6 were women (mean age, 62 yrs; range, 36-75 yrs). On average, patients were diagnosed with RA 11 years before pericardial disease developed. Twelve of 15 patients were seropositive for rheumatoid factor, 10 patients had radiographic evidence of erosions, and 7 patients had rheumatoid nodules. Cardiac tamponade was present in 11 of the 18 cases. Mean volume drained on the first pericardiocentesis was 504 +/- 264 ml (range 120-1000 ml). The fluid was an exudate with a mean protein concentration of 5 g/dl (range 3.3-51.1 g/dl). All cultures and cytologic findings were negative for bacteria and neoplastic cells. No serious complications resulted from echocardiographically guided pericardiocentesis. For 11 patients, a catheter was placed for intermittent drainage over an average of 3 days. Seven patients ultimately required a more definitive surgical procedure. CONCLUSION: Echocardiographically guided pericardiocentesis is a safe and effective treatment for this uncommon but serious complication of RA.

An unusual presentation of rheumatoid meningitis.

BACKGROUND: Central nervous system involvement in rheumatoid arthritis can rarely occur in the absence of systemic disease. Rheumatoid meningitis has not been reported to present as spells of neurologic dysfunction. PATIENT AND METHODS: The authors describe a woman with a history of well-controlled rheumatoid arthritis who presented with headaches and spells of focal neurological dysfunction. Brain magnetic resonance imaging, brain biopsy, and temporal artery biopsy were required to make the diagnosis of rheumatoid meningitis with arteritis. RESULTS: Neuroimaging revealed abnormal leptomeningeal enhancement. Necrotizing granulomatous inflammation was seen on meningeal and brain biopsy. A temporal artery biopsy showed evidence of arteritis without giant cells. CONCLUSIONS: The possibility of central nervous system involvement by rheumatoid arthritis should be considered in patients with a history of rheumatoid arthritis even in the absence of systemic symptoms. Making the diagnosis may require meningeal and brain biopsy. The condition may be steroid responsive.

Requirement for CD28 may not be absolute for collagen-induced arthritis: study with HLA-DQ8 transgenic mice.

CD28 is required to achieve optimal T cell activation to an Ag. To determine the role CD28 costimulation plays in collagen-induced arthritis, we have generated DQ8 transgenic, CD28-deficient mice. DQ8 mice deficient for CD28 had comparable numbers of CD4 and CD8 T cells as DQ8.CD28(+/+) mice. DQ8.CD28(-/-) mice develop collagen-induced arthritis with delayed onset and less severity than DQ8.CD28(+/+) mice. T cells from DQ8.CD28(-/-) mice did not respond to type II collagen efficiently in vitro, although the response to DQ8-restricted peptides was similar to that in the parent mice. There was no functional defect in T cells as observed by proliferation with Con A. Cytokine analysis from in vitro study showed the production of high levels of the inflammatory cytokine, IFN-gamma, in response to type II collagen. We observed an increase in CD4(+)CD28(-)NKG2D(+) cells after immunization, suggesting an important role for cells bearing this receptor in the disease process. CD28(-/-) mice also have an increased number of DX5(+) cells compared with CD28(+/+) mice, which can lead to the production of high levels of IFN-gamma. DQ8.CD28(-/-) mice had an increased number of cells bearing other costimulatory markers. Cells from DQ8.CD28(-/-) mice exhibited a lower proliferation rate and were resistant to activation-induced cell death compared with DQ8.CD28(+/+) mice. This study supports the idea that CD28 plays a crucial role in the regulation of arthritis. However, in the absence of CD28 signaling, other costimulatory molecules can lead to the development of disease, thus indicating that the requirement for CD28 may not be absolute in the development of arthritis.

Risk factors for methotrexate-induced abnormal laboratory monitoring results in patients with rheumatoid arthritis.

OBJECTIVE: To determine risk factors for methotrexate (MTX)-induced hepatic and hematologic laboratory abnormalities in patients with rheumatoid arthritis (RA). METHODS: Measurements of aspartate aminotransferase (AST), white blood cell counts, and platelet counts were collected in a database of patients with RA receiving MTX from 1991 through 2002. Potential risk factors for toxicity were recorded on each patient. RESULTS: Four hundred and eighty-one patients were followed for 2,323 person-years of MTX exposure. MTX was discontinued permanently because of abnormal laboratory test results in 22 patients (4.6%), the majority of whom (17/22, 77%) had elevated AST values. The body mass index (BMI) was significantly higher in those patients where MTX was permanently discontinued than in those in whom it was not (p < 0.03). Independent predictors of a significantly higher percentage of abnormal AST values were lack of folate supplementation (p < 0.001) and untreated hyperlipidemia (p < 0.02). Of the 17 patients in whom MTX was discontinued permanently because of an elevated AST value, 11/17 (65%) had either lack of folate supplementation or untreated hyperlipidemia. Hypoalbuminemia correlated independently with an increased percentage of abnormal platelet counts (p < 0.03). CONCLUSION: Lack of folate supplementation, untreated hyperlipidemia, and elevated BMI identified patients receiving MTX at risk for transaminase elevation, and low serum albumin was a risk factor for thrombocytopenia. Nonalcoholic fatty liver disease could be the underlying risk factor for transaminase elevation in patients with hyperlipidemia and obesity.

Relapsing polychondritis.

SUMMARY: Relapsing polychondritis is a unique, rare autoimmune disorder in which the cartilaginous tissues are the primary targets of destruction but the immune damage can spread to involve noncartilaginous tissues like the kidney, blood vessels, and so forth. The manifestations of the disease can take many different forms and the pathogenesis is still unclear. It may occur in a primary form or it may be associated with other disease states. This article summarizes important aspects of the disease with a focus on recent information regarding clinical manifestations, disease associations, pathogenesis, and advances in therapeutics.

Auricular chondritis in NOD.DQ8.Abetao (Ag7-/-) transgenic mice resembles human relapsing polychondritis.

Relapsing polychondritis is a multisystem autoimmune disease involving cartilage destruction but no known causative antigen. HLA-DQ8 has been associated with various autoimmune diseases in humans. To study the role of DQ8 in autoimmune diseases, we have generated transgenic mice expressing DQ8 (DQA1*0301, DQB1*0302) in a NOD background lacking endogenous class II molecules (Abetao). Upon immunization with type II collagen (CII), 85% of NOD.DQ8 mice develop severe experimental polychondritis, auricular chondritis, and polyarthritis, with clinical and histological similarities to relapsing polychondritis (RP) in humans. CII-immunized mice mount a T cell response and produce Ab's to type IX collagen (CIX) and self-CII. Transgene-negative littermates do not develop any serological and clinical manifestations following immunization. B10.DQ8 transgenic mice develop polyarthritis and Ab's to CII only. The susceptibility to auricular chondritis in NOD.DQ8 mice can be attributed to response to CIX. A higher number of activated cells, CD4+CD44(hi)CD62L(lo), and lower regulatory cells CD4+CD152+CD25+ were observed in NOD.DQ8 mice compared with B10.DQ8 mice. The NOD.DQ8 mice provide a model of RP with a high disease incidence and multiple organ involvement to investigate putative autoantigen and regulatory cells involved in disease pathogenesis. An experimental model restricted by the human class II molecule will be valuable when studying the role of various collagens in immunologic and pathologic responses in human RP.

Determinants of patient satisfaction in chronic illness.

OBJECTIVE: To determine whether primary care provided by generalists versus subspecialists resulted in different levels of patient satisfaction among persons with chronic illness. METHODS: A survey containing the Primary Care Provider Questionnaire and the Health Status Questionnaire (HSQ) was mailed to 2 population-based cohorts of patients with rheumatoid arthritis (RA) or diabetes mellitus (DM). All subjects were at least 35 years old and Rochester, Minnesota residents. Descriptive statistics, Spearman correlation coefficients, and multiple regression models were used to describe and compare the determinants of patient satisfaction. RESULTS: A total of 86 people (74% female) with RA and 208 people (56% male) with DM responded to the survey. Age range was 41-95 years and median disease duration was 8.7 years (RA) and 13.0 years (DM). Most patients described their health as fair or good. After adjusting for sex differences, RA patients were more likely than DM patients to report having a specialist as their primary care doctor. RA patients, whether reporting seeing a specialist or a generalist, had comparable HSQ physical health, mental health, social functioning, vitality, and bodily pain scores. DM patients seeing a specialist had more bodily pain and poorer physical functioning than those seeing a generalist. Across both chronic illnesses and physician specialties, median scores for patient satisfaction ranged from 17-18 for overall satisfaction (maximum 20); 30-33 for interpersonal skills (maximum 35); 23-26 for technical quality (maximum 30); and 20 for access to care (maximum 25). Multiple linear regression models revealed that 6.8-7.3% of the variation in satisfaction could be explained by HSQ scores, patient demographics, and physician specialty. CONCLUSION: Both RA and DM patients were highly satisfied with their care, regardless of the specialty of the provider. Physician specialty, patient demographics, and HSQ scores explained only a small proportion in the variation in satisfaction. These findings point to the need for additional research to further elucidate the determinants of patient satisfaction.

HLA class II influences the immune response and antibody diversification to Ro60/Sjögren's syndrome-A: heightened antibody responses and epitope spreading in mice expressing HLA-DR molecules.

Abs to Ro/SSA Ags in the sera of patients with systemic lupus erythematosus and Sjögren's syndrome are influenced by the HLA class II genes. To investigate the role of individual HLA class II genes in immune responses to human Ro60 (hRo60), mice lacking murine class II molecules and carrying either HLA genes DR2(DRB1*1502), DR3(DRB1*0301), DQ6(DQA1*0103/DQB1*0601), or DQ8(DQA1*0301/DQB1*0302), were immunized with rhRo60. The results show that hRo60 induces strong T and B cell responses in DR2, DR3, and DQ8 mice in comparison to weaker responses in DQ6 mice. In all mice, the majority of the dominant T cell epitopes were located in the amino portion (aa 61-185) and the carboxy portion (aa 381-525) of the hRo60 molecules. In contrast, the early dominant B cell epitopes were located in the middle and carboxy portion of the hRo60 molecule (aa 281-315 and 401-538). In DR2, DR3, and DQ8 mice, the B cell epitopes subsequently spread to the amino and carboxy portion of the hRo60 molecule but were limited to the middle and carboxy portion in DQ6 mice. The DR2 and DR3 mice produced the highest titers of immunoprecipitating Abs against hRo60 and native mouse Ro60. In addition, only DR2 mice exclusively produced immunoprecipitating Abs to native mouse Ro52 and Abs to mouse La by slot blot analysis, whereas in other strains of mice Abs to mouse La were cross-reactive with the immunogen. The results of the present study demonstrate the importance of HLA class II in controlling the immune responses to the Ro-ribonucleoprotein.