RORγt, a multitask nuclear receptor at mucosal surfaces.

RORγt is a nuclear hormone receptor that has followed an exponential success carrier. Its modest origins as an orphan receptor cloned from human pancreas blossomed within 15 years into a critical regulator of anti-microbial immunity and a major target in the fight against inflammatory pathologies. Here, I review its role as a transcription factor required for the generation of type 3 lymphoid cells, which induce the development of lymphoid tissues, provide resistance of epithelial stem cells to injury, maintain homeostasis with the symbiotic microbiota, orchestrate defense against extracellular microbes, and regulate allergic responses. RORγt is also an intriguing molecule that is regulated by the circadian rhythm and includes cholesterol metabolites as ligands. RORγt therefore links anti-microbial immunity with circadian rhythms and steroids, the logic of which remains to be understood.

[Austrian nutrition and lifestyle recommendations for gout and hyperuricemia]. / Österreichische Ernährungs- und Lebensstilempfehlungen bei Gicht und Hyperurikämie.

BACKGROUND: Gout is the most common inflammatory arthropathy in the Western world. This is mainly due to the high socioeconomic status, sufficient even superfluous nutrition, overweight and alcohol consumption. Despite adequate medication, information and advice on nutrition and lifestyle are one of the cornerstones in the management of these patients. OBJECTIVE: The aim was to provide recommendations on nutrition and lifestyle in cases of gout and hyperuricemia by a group of rheumatologists, based on a review of the most recent literature. MATERIALS AND METHODS: The study group for osteoarthritis and crystal arthropathies of the Austrian Society for Rheumatology and Rehabilitation (ÖGR) carried out a literature search on this topic. The selected papers were listed according to the level of evidence. RESULTS: Based on this literature search nine recommendations were generated and modified via a Delphi approach: four red "don'ts" concerning nutrition and beverages to be avoided, three green "do's" concerning favorable food as well as two blue general lifestyle recommendations. The format of the recommendations is a two-page leaflet with the list of recommendations, level of evidence, strength of recommendation and literature citations on the front page and a colored icon presentation of food and beverages in a circle, matching the colors of the written recommendations, on the reverse. CONCLUSION: For the first time in Austria, nine recommendations on nutrition, beverages and lifestyle for patients with gout and hyperuricemia were defined for everyday practice, as education material for patients and updated information for physicians.

The "psychomicrobiotic": Targeting microbiota in major psychiatric disorders: A systematic review.

The gut microbiota is increasingly considered as a symbiotic partner in the maintenance of good health. Metagenomic approaches could help to discover how the complex gut microbial ecosystem participates in the control of the host's brain development and function, and could be relevant for future therapeutic developments, such as probiotics, prebiotics and nutritional approaches for psychiatric disorders. Previous reviews focused on the effects of microbiota on the central nervous system in in vitro and animal studies. The aim of the present review is to synthetize the current data on the association between microbiota dysbiosis and onset and/or maintenance of major psychiatric disorders, and to explore potential therapeutic opportunities targeting microbiota dysbiosis in psychiatric patients.

Regulatory T cells promote a protective Th17-associated immune response to intestinal bacterial infection with C. rodentium.

Intestinal infection with the mouse pathogen Citrobacter rodentium induces a strong local Th17 response in the colon. Although this inflammatory immune response helps to clear the pathogen, it also induces inflammation-associated pathology in the gut and thus, has to be tightly controlled. In this project, we therefore studied the impact of Foxp3(+) regulatory T cells (Treg) on the infectious and inflammatory processes elicited by the bacterial pathogen C. rodentium. Surprisingly, we found that depletion of Treg by diphtheria toxin in the Foxp3(DTR) (DEREG) mouse model resulted in impaired bacterial clearance in the colon, exacerbated body weight loss, and increased systemic dissemination of bacteria. Consistent with the enhanced susceptibility to infection, we found that the colonic Th17-associated T-cell response was impaired in Treg-depleted mice, suggesting that the presence of Treg is crucial for the establishment of a functional Th17 response after the infection in the gut. As a consequence of the impaired Th17 response, we also observed less inflammation-associated pathology in the colons of Treg-depleted mice. Interestingly, anti-interleukin (IL)-2 treatment of infected Treg-depleted mice restored Th17 induction, indicating that Treg support the induction of a protective Th17 response during intestinal bacterial infection by consumption of local IL-2.

Development and function of intestinal innate lymphoid cells.

Innate lymphoid cells (ILCs) are generated from common lymphoid precursors, like lymphocytes, but do not express an antigen receptor. ILCs include Natural Killer (NK) cells, first described 38 years ago, as well as the more recently discovered lymphoid tissue inducer (LTi) cells, NK(22) cells and ILC2s. ILCs reflect many functions of CD4(+) T helper cells by expressing IFNγ, IL-17, IL-22 or IL-13. However, in contrast to T cells, they are not selected on the basis of antigen specificity, and expand and act shortly after stimulation. Therefore, ILCs play fundamental roles early in responses to infection and injury, in the maintenance of homeostasis, and possibly in the regulation of adaptive immunity. Here, we review the recent data on the development and role of RORγt(+) ILCs and ILC2s in intestinal homeostasis and defense.

A new vision of immunity: homeostasis of the superorganism.

The immune system is commonly perceived as an army of organs, tissues, cells, and molecules that protect from disease by eliminating pathogens. However, as in human society, a clear definition of good and evil might be sometimes difficult to achieve. Not only do we live in contact with a multitude of microbes, but we also live with billions of symbionts that span all the shades from mutualists to potential killers. Together, we compose a superorganism that is capable of optimal living. In that context, the immune system is not a killer, but rather a force that shapes homeostasis within the superorganism.

Autoantibody profiling in patients with very early rheumatoid arthritis: a follow-up study.

OBJECTIVE: To investigate time courses of autoantibody profiles in patients with early arthritis. PATIENTS AND METHODS: A total of 200 patients with very early arthritis (<3 months duration), among them 102 patients with a final diagnosis of rheumatoid arthritis (RA) and 98 with other rheumatic diseases, were followed up for several years. First follow-up testing was performed in all patients (mean 5 months from baseline), and 82 patients with RA and 35 patients without RA were available for last follow-up testing (mean 32 months from baseline). IgM-rheumatoid factor (RF) was measured by nephelometry, IgA-RF, IgG-RF and anti-cyclic citrullinated peptide antibodies (ACPA) by ELISA, and anti-RA33 antibodies were determined by immunoblotting. RESULTS: At baseline, IgA-RF was detectable in 29% and IgG-RF in 14% of patients with RA while IgM-RF>50 IU/ml (RF50) was positive in 45% of the patients; specificities were 97%, 99% and 96%, respectively. However, the vast majority of patients positive for IgA-RF or IgG-RF were also positive for RF50 or ACPA. During follow-up, the prevalence of ACPA slightly increased while prevalence of all RF subtypes and anti-RA33 decreased. Remarkably, the number of patients positive for RF50 and/or ACPA remained constant, and these patients had a highly increased risk for developing erosive disease in contrast to patients solely positive for anti-RA33. CONCLUSIONS: Testing for RF subtypes did not provide additional diagnostic information. Patients positive for RF50 and/or ACPA had an unfavourable prognosis, irrespectively of changes in the antibody profile during follow-up, whereas anti-RA33 positivity was inversely associated with erosiveness at baseline and at later time points.

The development of intestinal lymphoid tissues at the interface of self and microbiota.

Intestinal lymphoid tissues face the challenging task of inducing adaptive immunity to pathogens, yet maintaining homeostasis with the enormous commensal microbiota. To that aim, the ancient partnership between self and flora has resulted in the generation of a unique set of lymphoid tissues capable of constant large-scale reformatting. A first set of lymphoid tissues, the mesenteric lymph nodes and Peyer's patches, are programmed to develop in the sterile environment of the fetus, whereas a second set of lymphoid tissues, the tertiary lymphoid tissues, are induced to form by the microbiota and inflammation. The diversity of intestinal lymphoid tissues confers the flexibility required to adapt the number of immune inductive sites to the size of the flora and the extent of the pathogenic threat. The result is a functional superorganism combining self and microbes for the best possible symbiosis.

Autoantibody profiling as early diagnostic and prognostic tool for rheumatoid arthritis.

BACKGROUND: Early treatment prevents progression of joint damage in rheumatoid arthritis (RA), but diagnosis in early disease is impeded by lack of appropriate diagnostic criteria. OBJECTIVE: To study the value of rheumatoid factor (RF), anti-cyclic citrullinated peptide autoantibodies (anti-CCP), and anti-RA33 autoantibodies for diagnosis of RA and prediction of outcome in patients with very early arthritis. METHODS: The prospective follow up inception cohort included 200 patients with very early (<3 months) inflammatory joint disease. Autoantibodies were measured at baseline and analysed in a tree based model which aimed at determining the added diagnostic value of testing for anti-CCP and anti-RA33 as compared with RF alone. RESULTS: RA was diagnosed in 102 patients, while 98 developed other inflammatory arthropathies. Receiver operator curve analysis showed an optimum cut off level for RF at 50 U/ml, above which anti-CCP and anti-RA33 had no additional diagnostic value. Remarkably, RF >or=50 U/ml and anti-CCP showed similar sensitivity and high specificity for RA, but overlapped considerably. Anti-RA33 was less specific and did not correlate with RF or anti-CCP. Among patients with RA, 72% showed at least one of these three autoantibodies, compared with 15% of non-RA patients. RF >or=50 U/ml and anti-CCP were predictors of erosive disease, whereas anti-RA33 was associated with mild disease. CONCLUSIONS: Stepwise autoantibody testing in early inflammatory joint disease, starting with RF, followed by anti-CCP (in patients with RF <50 U/ml), and finally anti-RA33, should be used as a sensitive and effective strategy for distinguishing patients with RA at high risk for poor outcome.

Attitudes to early rheumatoid arthritis: changing patterns. Results of a survey.

OBJECTIVE: To determine if rheumatologists have changed their views on diagnosis and treatment of early rheumatoid arthritis (RA). METHODS: Three consecutive questionnaires were sent out to international rheumatologists in 1997, 2000, and 2003. The following aspects of early RA were covered: definition; patient referral time; diagnostic means; follow up intervals; and treatment strategies. All initial participants who responded to at least one of the follow up surveys were included in the analysis. RESULTS: RA is now defined by a smaller number of affected joints (monarthritis: 9.8% respondents in 1997 v 17.4% in 2003), and shorter symptom duration (<3 months: 65.5% in 1997 v 85.8% in 2003). Early referrals (<6 weeks) increased (8.9% in 1997 v 17.4% in 2003). Serological test for diagnosis was mostly rheumatoid factor (100% in 2003), but anti-CCP was already used by 17.4% in 2003. Follow up of patients with early RA intensified (every 2 weeks: 16.1% in 1997 v 30.4% in 2003; every month: 47.8% in 2003 v 64.3% in 1997). Treatment with disease modifying antirheumatic drugs (DMARDs) mainly comprised methotrexate, sulfasalazine, and antimalarial drugs. Leflunomide was among the two favourite DMARDs of 10.9% in 2003, whereas no biological agent was so. In 2003, 46.7% respondents started treatment with DMARDs if RA was suspected (30.9% in 1997); no one waited for erosions to occur (7.3% in 1997). CONCLUSION: The data obtained in this study suggest that the concept of diagnosing and treating RA early is accepted by a large proportion of the rheumatological community.

Benefit of very early referral and very early therapy with disease-modifying anti-rheumatic drugs in patients with early rheumatoid arthritis.

OBJECTIVE: Delay of disease-modifying anti-rheumatic drug (DMARD) therapy is a major contributing factor for poor outcome in rheumatoid arthritis (RA). Although early therapy has been shown to be particularly effective, there is still uncertainty about the optimal time point of DMARD introduction. We wanted to test if a therapeutic window of opportunity may exist within the first few months of the disease. METHODS: In this case-control parallel-group study, 20 very early RA (VERA) patients with median disease duration of 3 months were age and gender matched to a group of 20 late early RA (LERA) patients with median disease duration of 12 months until first DMARD initiation. Follow-up time was 36 months. Primary outcome measures were the disease activity score (DAS28) and radiological joint destruction using the Larsen method. RESULTS: Already after 3 months of DMARD therapy we found a significant difference of improvement in favour of the VERA patients in the DAS28. This trend continued over the study period. At study end the DAS28 showed an improvement of 2.8+/-1.5 in the VERA vs 1.7+/-1.2 in the LERA group (P(c)<0.05). The Larsen scores showed a statistically significant retardation of progression in the VERA compared with the LERA. CONCLUSION: Our results indicate that there is a window of opportunity for highly successful treatment of RA in the first year, and especially within the first 3 months of therapy. Thus, early diagnosis and therapy may be the crucial step in achieving optimal control of disease progression and prognosis in RA.

Survival and effectiveness of leflunomide compared with methotrexate and sulfasalazine in rheumatoid arthritis: a matched observational study.

OBJECTIVE: To determine the survival and clinical effectiveness of leflunomide (LEF) compared with methotrexate (MTX) and sulfasalazine (SSZ) for RA in an observational study. METHODS: An observational database of 1088 patients and 5141 patient years of DMARD treatment (2680 courses) from two academic hospitals was filtered for treatment with LEF, MTX, and SSZ. LEF treatment groups were matched for patients' age, baseline ESR, number of previous DMARDs, and hospital cohort with MTX and SSZ treatment groups. For these treatments, Kaplan-Meier analyses of time until the drug was discontinued (drug "survival"), and the effectiveness and safety of continuation of treatment, were performed. The change in disease activity markers (CRP, ESR) was compared between the groups. RESULTS: The median dose during the study increased from 10 to 15 mg MTX/week and from 1.5 to 2.0 g SSZ/day. Matched survival analysis showed better retention rates for MTX (mean (SEM) survival 28 (1) months) than for LEF (20 (1) months; p=0.001), whereas retention rates of SSZ (23 (1) months) were similar to those of LEF (p=NS). Treatments were stopped earlier because of adverse events (AEs, 3 months) than because of ineffectiveness (IE, 10 months; p<0.001). LEF and MTX were less likely to be stopped because of AEs than SSZ. LEF courses were stopped earlier for AEs (p<0.001) than MTX. CONCLUSIONS: Current dosing strategies should be re-evaluated, and coping strategies for common AEs should be investigated. This will be necessary to achieve better drug retention of LEF. At present, MTX continues to be the most effective drug in clinical practice.

A simplified disease activity index for rheumatoid arthritis for use in clinical practice.

OBJECTIVE: The objective of this study was to verify the usefulness of a simple disease activity index (SDAI) for rheumatoid arthritis (RA). METHODS: The SDAI is the numerical sum of five outcome parameters: tender and swollen joint count (based on a 28-joint assessment), patient and physician global assessment of disease activity [visual analogue scale (VAS) 0-10 cm] and level of C-reactive protein (mg/dl, normal <1 mg/dl). Analysis initially focused on MN301, one of the three phase III clinical trials of leflunomide, in order to assess possible correlations between the SDAI and the Health Assessment Questionnaire (HAQ) and Disease Activity Score 28 (DAS 28). Results were then compared with the other two trials, MN302 and US301. A total of 1839 patients were evaluated. At baseline, 6 and 12 months, the SDAI, DAS 28, American College of Rheumatology (ACR) response criteria and mean HAQ scores were determined for each patient and compared by linear regression for significant correlation. The SDAI was compared qualitatively to the ACR 20% at 3, 6 and 12 months. The index was further validated by comparing the SDAI with survey results obtained from rheumatologists' evaluations of disease activity in test cases. The survey results included defining categorical changes in the SDAI indicating major, minor or no improvement in disease activity in response to treatment. Changes in total Sharp score at 6 and 12 months of treatment were determined for each of these categories of the SDAI and for comparable categories of the DAS 28. RESULTS: The mean SDAI calculated for patients at baseline in study MN301 was 50.06 (range 25.10-96.10) and was, respectively, 50.55 (range 22.10-98.10) and 43.20 (range 12.90-78.20) in studies MN302 and US301. In all three trials, the SDAI was correlated with a high level of statistical significance to the DAS 28 and HAQ scores at baseline, endpoint and change at endpoint. Patients achieving the ACR 20, 50, 70 or 90% response showed proportionate changes in the SDAI. Analysis of surveyed physician responses showed a significant association between the perception of disease activity and the SDAI, as well as changes in the SDAI. Qualitative analysis of radiographic progression at 6 and 12 months for patients showing either major, minor or no improvement of the SDAI showed correspondingly larger increases of the total Sharp score at 12 months. CONCLUSION: The SDAI is a valid and sensitive assessment of disease activity and treatment response that is comparable with the DAS 28 and ACR response criteria; it is easy to calculate and therefore a viable tool for day-to-day clinical assessment of RA treatment. Overall results indicate that the SDAI has content, criterion and construct validity.

The Austrian Early Arthritis Registry.

The Austrian Early Arthritis Registry (Austrian Early Arthritis Action, EAA) enrols and follows patients with inflammatory arthritis of very short (< 12 weeks) duration. Currently, data on 375 patients (almost 2000 individual follow-up examinations) have been entered into the EA database. Evaluations of data from 182 patients with a follow-up of at least one year are available. 65% of these patients have RA, as diagnosed using the ACR classification criteria in a cumulative fashion. Approximately 15% of these patients still have no established diagnosis and are being carried forward and observed as cases of "undifferentiated arthritis". In RA patients, the mean DAS 28 decreased significantly from an initial mean score of 5.5 (high disease activity) into the range of low disease activity. At the end of one year a DAS 28 of < 3.2 was observed in 52% of the RA patients. Radiological progression in these RA patients, who also received treatment very early, appears to be less severe than in other cohorts, although direct comparisons are impossible due to different methods of patient selection. In addition, the serological data from our cohort in cooperation with other study groups will allow development and validation of possible prediction algorithms for early arthritis patients which could improve the diagnostic and therapeutic approach to this patient group.

Practical progress in realisation of early diagnosis and treatment of patients with suspected rheumatoid arthritis: results from two matched questionnaires within three years.

BACKGROUND: Early diagnosis and treatment with disease modifying antirheumatic drugs (DMARDs) have been advocated for patients with rheumatoid arthritis (RA). This survey focuses on the individual definitions and treatment modalities of rheumatologists, and aims at determining the practical realisation of these concepts. METHODS: A questionnaire to be self completed was handed out at the EULAR Symposium 1997. The main issues dealt with were definition, referral time, diagnosis, follow up, and treatment of early RA. Of the 111 participants, who were from all continents and all age groups, 85 (77%) gave their name and address. In 2000, the same questionnaire was sent to these 85 primary respondents. Forty four questionnaires (52%) were returned, and their results were matched and further evaluated. RESULTS: The definition of early RA was heterogeneous, but two of three rheumatologists use the term "early" for symptoms shorter than three months. There was a drift towards acceptance of involvement of fewer affected joints. Serological tests obtained for early diagnosis were mostly rheumatoid factor and antinuclear antibodies, usually in combination (approximately 70%), while other tests (antikeratin antibodies, antiperinuclear factor, anti-RA33) were used rarely, but increasingly (21-25% all together). No significant change in the lag time of referral to the specialist of patients with suspected early RA was seen within these three years (<3 months for 50%, >6 months for 20%), while the proportion followed up during the first three months increased. At both times, every second rheumatologist started DMARD treatment only when the 1987 American College of Rheumatology (ACR) criteria were fulfilled. However, in 1997 about 10% were willing to wait for erosions before starting DMARDs, while none did so in 2000. Methotrexate, sulfasalazine, and antimalarial drugs were the most commonly prescribed DMARDs in early RA, with the first two of these still being in increasing use. CONCLUSION: The understanding of "early" rheumatoid arthritis is heterogeneous, but the vast majority of the rheumatologists surveyed regard symptom duration of <3 months as early. Rheumatoid factor was the most useful laboratory support in early diagnosis. Because there has been no shortening of referral time of patients with new RA within the past three years, and many rheumatologists start DMARDs only when the ACR criteria are fulfilled, it is concluded that guidelines for early referral, as well as for early (rheumatoid) arthritis, are needed.

A critical role for the T cell receptor alpha-chain connecting peptide domain in positive selection of CD1-independent NKT cells.

Natural killer T (NKT) cells are a subset of mature alpha beta TCR(+) cells that co-express NK lineage markers. Whereas most NKT cells express a canonical Valpha14/Vbeta8.2 TCR and are selected by CD1d, a minority of NKT cells express a diverse TCR repertoire and develop independently of CD1d. Little is known about the selection requirements of CD1d-independent NKT cells. We show here that NKT cells develop in RAG-deficient mice expressing an MHC class II-restricted transgenic TCR (Valpha2/Vbeta8.1) but only under conditions that lead to negative selection of conventional T cells. Moreover development of NKT cells in these mice is absolutely dependent upon an intact TCR alpha-chain connecting peptide domain, which is required for positive selection of conventional T cells via recruitment of the ERK signaling pathway. Collectively our data demonstrate that NKT cells can develop as a result of high avidity TCR/MHC class II interactions and suggest that common signaling pathways are involved in the positive selection of CD1d-independent NKT cells and conventional T cells.

CD1d-restricted NK T cells are dispensable for specific antibody responses and protective immunity against liver stage malaria infection in mice.

Immunization with a single dose of irradiated sporozoites is sufficient to induce protection against malaria in wild-type mice. Although this protection is classically attributed to conventional CD4+ and CD8+ T cells, several recent reports have suggested an important role for CD1-restricted NK T cells in immunity to malaria. In this study, we directly compared the ability of C57BL/6 wild-type and CD1-deficient mice to mount a protective immune response against Plasmodium berghei sporozoites. Our data indicate that CD1-restricted NK T cells are not required for protection in this model system. Moreover, specific IgG antibody responses to the P. berghei circumsporozoite repeat sequence were also unaffected by CD1 deficiency. Collectively, our data demonstrate that CD1-restricted NK T cells are dispensable for protective immunity to liver stage P. berghei infection.

Selective bystander proliferation of memory CD4+ and CD8+ T cells upon NK T or T cell activation.

Ag-experienced or memory T cells have increased reactivity to recall Ag, and can be distinguished from naive T cells by altered expression of surface markers such as CD44. Memory T cells have a high turnover rate, and CD8(+) memory T cells proliferate upon viral infection, in the presence of IFN-alphabeta and/or IL-15. In this study, we extend these findings by showing that activated NKT cells and superantigen-activated T cells induce extensive bystander proliferation of both CD8(+) and CD4(+) memory T cells. Moreover, proliferation of memory T cells can be induced by an IFN-alphabeta-independent, but IFN-gamma- or IL-12-dependent pathway. In these conditions of bystander activation, proliferating memory (CD44(high)) T cells do not derive from activation of naive (CD44(low)) T cells, but rather from bona fide memory CD44(high) T cells. Together, these data demonstrate that distinct pathways can induce bystander proliferation of memory T cells.

The synthetic, oxidized C-terminal fragment of the Plasmodium berghei circumsporozoite protein elicits a high protective response.

A polypeptide of 69 amino acids (PbCS 242-310) encompassing the C-terminal region of the circumsporozoite protein of Plasmodium berghei (PbCS) was generated using solid-phase peptide synthesis. The immunological and protective properties of peptide PbCS 242-310 were studied in BALB/c mice (H-2d). Two subcutaneous injections, in the presence of IFA at the base of the tail, generated (i) high titers of anti-peptide antibodies which also recognized the native P. berghei CS protein, (ii) cytolytic T cells specific for the Kd-restricted peptide PbCS 245-253 and (iii) partial CD8+-dependent protection against sporozoite-induced malaria. The same frequencies of peptide PbCS 245-253 specific CD8+ T cells were found by IFN-gamma ELISPOT in the draining lymph nodes of animals immunized with the short optimal CTL peptide 245-253 or with the polypeptide 242-310, indicating that the longer polypeptide can be processed and presented in vivo in the context of MHC class I as efficiently as the short CTL peptide. Interestingly, higher levels of IFN-gamma producing CD8 T cells and protection were observed when the four cysteine residues present in the C-terminal peptide were fully oxidized. These findings underline the potential importance of the chemical nature of the C-terminal fragment on the activation of the immune system and concomitant protection.