New risk model is able to identify patients with a low risk of progression in systemic sclerosis.

OBJECTIVES: To develop a prediction model to guide annual assessment of systemic sclerosis (SSc) patients tailored in accordance to disease activity. METHODS: A machine learning approach was used to develop a model that can identify patients without disease progression. SSc patients included in the prospective Leiden SSc cohort and fulfilling the ACR/EULAR 2013 criteria were included. Disease progression was defined as progression in ≥1 organ system, and/or start of immunosuppression or death. Using elastic-net-regularisation, and including 90 independent clinical variables (100% complete), we trained the model on 75% and validated it on 25% of the patients, optimising on negative predictive value (NPV) to minimise the likelihood of missing progression. Probability cutoffs were identified for low and high risk for disease progression by expert assessment. RESULTS: Of the 492 SSc patients (follow-up range: 2-10 years), disease progression during follow-up was observed in 52% (median time 4.9 years). Performance of the model in the test set showed an AUC-ROC of 0.66. Probability score cutoffs were defined: low risk for disease progression (<0.197, NPV:1.0; 29% of patients), intermediate risk (0.197-0.223, NPV:0.82; 27%) and high risk (>0.223, NPV:0.78; 44%). The relevant variables for the model were: previous use of cyclophosphamide or corticosteroids, start with immunosuppressive drugs, previous gastrointestinal progression, previous cardiovascular event, pulmonary arterial hypertension, modified Rodnan Skin Score, creatine kinase and diffusing capacity for carbon monoxide. CONCLUSION: Our machine-learning-assisted model for progression enabled us to classify 29% of SSc patients as 'low risk'. In this group, annual assessment programmes could be less extensive than indicated by international guidelines.

Five-year outcomes of probable rheumatoid arthritis treated with methotrexate or placebo during the first year (the PROMPT study).

OBJECTIVE: To assess long-term disease outcome of undifferentiated arthritis (UA) after initial treatment with methotrexate (MTX) or placebo. METHODS: 110 patients with UA were randomised to receive MTX (n=55) or placebo (n=55) for 1 year. After 5 years the outcomes for diagnosis (rheumatoid arthritis, 1987 criteria (RA (1987)), UA or UA in remission) and radiographic progression were compared between treatment arms and anti-citrullinated protein antibody (ACPA)-positive and -negative patients. Outcomes were recalculated for patients who, with hindsight, might have been classified at baseline as having RA according to the 2010 criteria (RA (2010)). RESULTS: 25 patients in the MTX group and 29 in the placebo group progressed to RA (1987) (p=0.45). MTX delayed progression from UA to RA (1987) but only in ACPA-positive patients. Drug-free remission was achieved in 35 patients, 20 of whom were initially treated with MTX, and 32 were ACPA-negative. ACPA-positive patients had more radiographic progression, regardless of treatment. Forty-three patients (39%) could be reclassified as having had RA (2010) at baseline, 6/24 (25%) of whom achieved remission after placebo treatment. CONCLUSIONS: After 5 years there is no lasting benefit of a 1 year initial course of MTX for patients with undifferentiated arthritis, compared with initial placebo. Progression to classifiable RA was not suppressed, drug-free remission not induced and the progression of radiological damage was similar in both groups. Reclassification at baseline with the 2010 criteria showed that 25% of patients with RA (2010) achieved spontaneous drug-free remission.

Validity of the disease activity score in undifferentiated arthritis.

OBJECTIVE: To study whether the Disease Activity Score (DAS) is a valid measure of disease activity in undifferentiated arthritis (UA). METHODS: Data from a randomized, double-blind, placebo-controlled trial of methotrexate (MTX) and placebo involving 110 patients with UA were used. Data included baseline and 3, 6, 9, and 12 months, as well as diagnosis at 18 months. Validity of the DAS was analyzed using factor analysis, correlations with disease activity variables, correlations with changes in disability and joint damage, differences in DAS between diagnoses, and detecting the difference between placebo and MTX. RESULTS: Three disease activity factors were retrieved from the disease activity variables: patient reported outcomes, tender and swollen joints, and acute phase reactants. The DAS had its highest correlations (r > 0.77) with tender joint counts, followed by swollen joint counts (r > 0.63) and patient reported outcomes (r > 0.30), but the DAS correlated less with C-reactive protein levels (r = 0.32). Over time, the DAS was related to the Health Assessment Questionnaire response with an odds ratio of 4.1 (95% confidence interval 2.1-8.0), but not with change in joint damage. At 18 months, the mean DAS was 2.6 for rheumatoid arthritis patients, 2.2 for UA patients, and 1.9 for patients in remission (P = 0.001). The DAS discriminated better than all single variables between MTX and placebo, with a Guyatt's effect size of 0.89. CONCLUSION: The DAS appears to be a reasonably valid measure of disease activity for use in UA clinical trials.

Functional killer Ig-like receptors on human memory CD4+ T cells specific for cytomegalovirus.

Although very few CD4(+) T cells express killer Ig receptors (KIR), a large proportion of CD4(+) T cells with a late memory phenotype, characterized by the absence of CD28, does express KIR. Here, we show that KIR expression on CD4(+) T cells is also associated with memory T cell function, by showing that the frequency of CMV-specific cells is higher in CD4(+)KIR(+) than CD4(+)KIR(-) T cells. In addition, engagement of an inhibitory KIR inhibited the CMV-specific proliferation of these CD4(+)KIR(+) memory T cells, but had no detectable effect on cytokine production. Our data reveal that, in marked contrast with CD8(+) T cells, the activity of a subset of CMV-specific CD4(+) T cells is modulated by HLA class I-specific KIR. Thus, the CMV-induced down-regulation of HLA class I may in fact enhance memory CMV-specific CD4(+) T cell responses restricted by HLA class II.

Suppressor activity among CD4+,CD25++ T cells is discriminated by membrane-bound tumor necrosis factor alpha.

OBJECTIVE: Previous studies have shown that the suppressive capacity of CD4+,CD25++ T cells is compromised in patients with rheumatoid arthritis (RA) and restored by anti-tumor necrosis factor alpha (anti-TNFalpha) therapy. Given the lack of specific cell surface markers for human Treg cells, this study aimed to define surface markers for identifying and enriching Treg cells with enhanced regulatory ability within the CD4+,CD25++ T cell compartment and to provide additional understanding of the effects of anti-TNFalpha antibodies in humans. METHODS: The expression of membrane-bound TNFalpha in human peripheral blood CD4+ T cells was analyzed by flow cytometry in healthy individuals and RA patients before and after anti-TNFalpha treatment. Membrane-bound TNFalpha-positive and TNFalpha-negative CD4+,CD25++ T cells were purified by fluorescence-activated cell sorting, and their suppressive capacity was assessed in vitro by a standard suppression assay. RESULTS: A substantial number of CD4+,CD25++ T cells expressed membrane-bound TNFalpha. Membrane-bound TNFalpha-positive CD4+,CD25++ T cells displayed reduced antiinflammatory cytokine production and less potent suppressor capacity, since 4 times more cells were required to achieve 50% inhibition compared with their membrane-bound TNFalpha-negative counterparts. Treatment of RA patients with TNFalpha-specific antibodies led to a reduction in the number of membrane-bound TNFalpha-positive CD4+,CD25++ T cells from peripheral blood. CONCLUSION: Our data indicate that the absence of membrane-bound TNFalpha on CD4+,CD25++ T cells can be used to characterize and enrich for Treg cells with maximal suppressor potency. Enrichment of membrane-bound TNFalpha-negative CD4+,CD25+ cells in the CD4+,CD25++ T cell compartment may contribute to restoring the compromised suppressive ability of CD4+,CD25++ T cell populations in RA patients after anti-TNFalpha treatment.

Efficacy of methotrexate treatment in patients with probable rheumatoid arthritis: a double-blind, randomized, placebo-controlled trial.

OBJECTIVE: To determine whether patients with undifferentiated arthritis (UA; inflammatory, nontraumatic arthritis that cannot be diagnosed using current classification criteria) benefit from treatment with methotrexate (MTX). METHODS: The PRObable rheumatoid arthritis: Methotrexate versus Placebo Treatment (PROMPT) study was a double-blind, placebo-controlled, randomized, multicenter trial involving 110 patients with UA who fulfilled the American College of Rheumatology (ACR) 1958 criteria for probable RA. Treatment started with MTX (15 mg/week) or placebo tablets, and every 3 months the dosage was increased if the Disease Activity Score was >2.4. After 12 months, the study medication was tapered and discontinued. Patients were followed up for 30 months. When a patient fulfilled the ACR criteria for RA (primary end point), the study medication was changed to MTX. Joint damage was scored on radiographs of the hands and feet. RESULTS: In 22 of the 55 patients (40%) in the MTX group, UA progressed to RA compared with 29 of 55 patients (53%) in the placebo group. However, in the MTX group, patients fulfilled the ACR criteria for RA at a later time point than in the placebo group (P = 0.04), and fewer patients showed radiographic progression over 18 months (P = 0.046). CONCLUSION: This study provides evidence for the efficacy of MTX treatment in postponing the diagnosis of RA, as defined by the ACR 1987 criteria, and retarding radiographic joint damage in UA patients.

Induction of EAE by T cells specific for alpha B-crystallin depends on prior viral infection in the CNS.

While myelin-reactive T cells are widely believed to play a pathogenic role in multiple sclerosis (MS), no substantial differences appear to exist in T-cell responses to myelin antigens between MS patients and healthy subjects. As an example, indistinguishable peripheral T-cell responses and serum antibody levels have been found in MS patients and healthy controls to alpha B-crystallin, a dominant antigen in MS-affected brain myelin. This suggests that additional factors are relevant in allowing myelin-reactive T cells to become pathogenic. In this study, we examined whether the inflammatory state of the CNS is relevant to the pathogenicity of alpha B-crystallin-specific T cells in mice. In normal mice, T-cell responses against alpha B-crystallin are limited by robust immunological tolerance. Reactive T cells were therefore generated in alpha B-crystallin-deficient mice, and these T cells were transferred into C57BL/6 recipients. While such a transfer in itself never induced any clinical signs of experimental autoimmune encephalomyelitis (EAE) in healthy recipient mice, acute EAE could be induced in animals that had been infected 7 days before with the avirulent A7(74) strain of Semliki Forest virus (SFV). SFV infection alone did not induce clinical disease, nor did it alter the expression levels of the target antigen. Our findings indicate that at least in mice, alpha B-crystallin-specific T cells can trigger EAE but only when prior viral infection has induced an inflammatory state in the CNS that helps recruit and activate T cells.

A prediction rule for disease outcome in patients with recent-onset undifferentiated arthritis: how to guide individual treatment decisions.

OBJECTIVE: In patients with undifferentiated arthritis (UA), methotrexate is effective for inhibiting symptoms, structural damage, and progression to rheumatoid arthritis (RA). However, 40-50% of patients with UA experience spontaneous remission. Thus, adequate decision-making regarding treatment of patients with early UA requires identification of those patients in whom RA will develop. METHODS: A prediction rule was developed using data from the Leiden Early Arthritis Clinic, an inception cohort of patients with recent-onset arthritis (n = 1,700). The patients who presented with UA were selected (n = 570), and progression to RA or another diagnosis in this group was monitored for 1 year of followup. The clinical characteristics with independent predictive value for the development of RA were selected using logistic regression analysis. The diagnostic performance of the prediction rule was evaluated using the area under the curve (AUC). Cross-validation controlled for overfitting of the data (internal validation). An independent cohort of patients with UA was used for external validation. RESULTS: The prediction rule consisted of 9 clinical variables: sex, age, localization of symptoms, morning stiffness, the tender joint count, the swollen joint count, the C-reactive protein level, rheumatoid factor positivity, and the presence of anti-cyclic citrullinated peptide antibodies. Each prediction score varied from 0 to 14 and corresponded to the percent chance of RA developing. For several cutoff values, the positive and negative predictive values were determined. The AUC values for the prediction rule, the prediction model after cross-validation, and the external validation cohort were 0.89, 0.87, and 0.97, respectively. CONCLUSION: In patients who present with UA, the risk of developing RA can be predicted, thereby allowing individualized decisions regarding the initiation of treatment with disease-modifying antirheumatic drugs in such patients.

Functional regulatory immune responses against human cartilage glycoprotein-39 in health vs. proinflammatory responses in rheumatoid arthritis.

The class of immune response against autoantigens could profoundly influence the onset and/or outcome of autoimmune diseases. Until now, there is only limited information on the antigen-specific balance between proinflammatory and regulatory responses in humans. Here we analyzed the natural immune response against a candidate autoantigen in rheumatoid arthritis, human cartilage glycoprotein-39 (HC gp-39). Peripheral blood mononuclear cells from healthy individuals reacted against HC gp-39 with the production of IL-10 but not IFN-gamma. Ex vivo assays indicated that the naturally occurring HC gp-39-specific immune response in bulk is powerful enough to suppress antigen-specific recall responses, demonstrating that rather than being unresponsive, the HC gp-39-directed immune response in healthy individuals shows a strong bias toward a regulatory phenotype. Moreover, CD4(+) T cell lines directed against HC gp-39 expressed CD25, glucocorticoid-induced tumor necrosis factor receptor, and Foxp3 molecules and were capable of suppressing antigen-specific T cell responses. Cell-cell contact was required for this suppression. As opposed to healthy individuals, the HC gp-39-directed immune response in 50% of patients with rheumatoid arthritis exhibits polarization toward a proinflammatory T helper 1 phenotype and is significantly less powerful in suppressing antigen-specific recall responses. Together these findings indicate that the presence of HC gp-39-specific immune responses in healthy individuals may have an inhibitory effect on inflammatory responses in areas where HC gp-39 is present. Furthermore, these data indicate that the class of HC gp-39-directed immune response in rheumatoid arthritis patients has shifted from an antiinflammatory toward a proinflammatory phenotype.