Elise Siegert

Low-dose interleukin-2 selectively corrects regulatory T cell defects in patients with systemic lupus erythematosus

Objectives Defects in regulatory T cell (Treg) biology have been associated with human systemic autoimmune diseases, such as systemic lupus erythematosus (SLE). However, the origin of such Treg defects and their significance in the pathogenesis and treatment of SLE are still poorly understood. Methods Peripheral blood mononuclear cells (PBMC) from 61 patients with SLE and 52 healthy donors and in vitro IL-2 stimulated PBMC were characterised by multicolour flow cytometry. Five patients with refractory SLE were treated daily with subcutaneous injections of 1.5 million IU of human IL-2 (aldesleukin) for five consecutive days, and PBMC were analysed by flow cytometry. Results Patients with SLE develop a progressive homeostatic dysbalance between Treg and conventional CD4+ T cells in correlation with disease activity and in parallel display a substantial reduction of CD25 expression on Treg. These Treg defects resemble hallmarks of IL-2 deficiency and lead to a markedly reduced availability of functionally and metabolically active Treg. In vitro experiments revealed that lack of IL-2 production by CD4+ T cells accounts for the loss of CD25 expression in SLE Treg, which could be selectively reversed by stimulation with low doses of IL-2. Accordingly, treatment of patients with SLE with a low-dose IL-2 regimen selectively corrected Treg defects also in vivo and strongly expanded the Treg population. Conclusions Treg defects in patients with SLE are associated with IL-2 deficiency, and can be corrected with low doses of IL-2. The restoration of endogenous mechanisms of immune tolerance by low-dose IL-2 therapy, thus, proposes a selective biological treatment strategy, which directly addresses the pathophysiology in SLE.

Rapid induction of clinical remission by low-dose interleukin-2 in a patient with refractory SLE

Interleukin-2 (IL-2) is crucial for the growth and survival of regulatory T cells (Treg) and, thus, for the control of autoimmunity.1 ,2 In previous studies, we have proven a causal relationship between an acquired IL-2-deficiency, defects in Treg biology and the development of systemic lupus erythematosus (SLE).3 Accordingly, we showed that compensation of IL-2 deficiency by IL-2 therapy corrects associated Treg defects and ameliorates already established disease in lupus-prone mice.3 In line with this, two independent clinical studies showed recently that low-dose IL-2 induced expansion of the Treg pool and reduced clinical symptoms in two different immunological diseases without known IL-2 deficiency.4 ,5 These promising clinical findings in conjunction with preclinical data3 ,6 ,7 provide strong rationales for an IL-2-based immunotherapy of SLE in order to restore Treg activity and, thus, to re-establish endogenous mechanisms of tolerance that can counteract autoimmunity. Here we report a rapid and robust reduction of disease activity in parallel with a remarkable expansion of the Treg population by low-dose IL-2 therapy in one patient with a long-term history of SLE and increased disease activity refractory …

Analysis of omega-3 and omega-6 fatty acid-derived lipid metabolite formation in human and mouse blood samples

Mass spectrometry techniques have enabled the identification of different lipid metabolites and mediators derived from omega-6 and omega-3 polyunsaturated fatty acids (n-6 and n-3 PUFA) that are implicated in various biological processes. However, the broad-spectrum assessment of physiologically formed lipid metabolites and mediators in blood samples has not been presented so far. Here lipid mediators and metabolites of the n-6 PUFA arachidonic acid as well as the long-chain n-3 PUFA eicosapentaenoic acids (EPA) and docosahexaenoic acid (DHA) were measured in human blood samples as well as in mouse blood. There were detectable but mostly very low amounts of the assayed compounds in human native plasma samples, whereas in vitro activation of whole blood with the calcium ionophore A23187 led to highly significant increases of metabolite formation, with a predominance of the 12-lipoxygenase (12-LOX) products 12-hydroxyeicosatetraenoic acid (12-HETE), 12-hydroxyeicosapentaenoic acid (12-HEPE) and 14-hydroxydocosahexaenoic acid (14-HDHA). A23187 activation also led to significant increases in the formation of 5-LOX products including leukotriene B(4) (LTB(4)), leukotriene B(5) (LTB(5)) as well as of 15-LOX products and prostaglandin E(2) (PGE(2)) and thromboxane B(2) (TXB(2)). Levels were similar or even higher in A23187-activated mouse blood. The approach presented here thus provides a protocol for the comprehensive and concomitant assessment of the generation capacity of n-3 and n-6 PUFA-derived lipid metabolites as well as thromboxanes and prostaglandins in human and murine blood samples. Further studies will now have to evaluate lipid metabolite generation capacity in different physiological and pathophysiological contexts.

Angiotensin receptor type 1 and endothelin receptor type A on immune cells mediate migration and the expression of IL-8 and CCL18 when stimulated by autoantibodies from systemic sclerosis patients.

IntroductionAgonistic autoantibodies (Aabs) against the angiotensin II receptor type 1 (AT1R) and the endothelin receptor type A (ETAR) have been identified in patients with systemic sclerosis (SSc). In our present study, we examined the expression of the AT1R and the ETAR in human immune cells and the pathological effects mediated through these receptors by their corresponding Aabs.MethodsProtein expression of AT1R and ETAR on peripheral blood mononuclear cells (PBMCs) from healthy individuals and SSc patients was analyzed using flow cytometry, and mRNA expression of both receptors in PBMCs from healthy donors was examined by real-time PCR. In addition, PBMCs from healthy donors were stimulated in vitro with affinity-purified immunoglobulin G (IgG) fractions from SSc patients positive for AT1R and ETAR Aabs, as well as with IgG from healthy donors serving as controls. Alterations in cell surface marker expression, cytokine secretion and chemotactic motility were analyzed using flow cytometry, enzyme-linked immunosorbent assays and chemotaxis assays, respectively. The results were correlated with the characteristics and clinical findings of the IgG donors.ResultsBoth AT1R and ETAR were expressed on PBMCs in humans. Protein expression of both receptors was decreased in SSc patients compared with that of healthy donors and declined during the course of disease. IgG fractions of SSc patients positive for AT1R and ETAR Aabs induced T-cell migration in an Aab level–dependent manner. Moreover, IgG of SSc patients stimulated PBMCs to produce more interleukin 8 (IL-8) and chemokine (C-C motif) ligand 18 (CCL18) than did the IgG of healthy donors. All effects were significantly reduced by selective AT1R and ETAR antagonists. Statistical analysis revealed an association of SSc-IgG induced high IL-8 concentrations with an early disease stage and of high CCL18 concentrations with lung fibrosis onset and vascular complications in the respective IgG donors.ConclusionIn our present study, we could demonstrate the expression of both AT1R and ETAR on human peripheral T cells, B cells and monocytes. The decreased receptor expression in SSc patients, the inflammatory and profibrotic effects upon Aab stimulation of PBMCs in vitro and the associations with clinical findings suggest a role for Aab-induced activation of immune cells mediated by the AT1R and the ETAR in the pathogenesis or even the onset of the disease.

The European Scleroderma Trials and Research group (EUSTAR) task force for the development of revised activity criteria for systemic sclerosis: Derivation and validation of a preliminarily revised EUSTAR activity index

Background Validity of European Scleroderma Study Group (EScSG) activity indexes currently used to assess disease activity in systemic sclerosis (SSc) has been criticised. Methods Three investigators assigned an activity score on a 0–10 scale for 97 clinical charts. The median score served as gold standard. Two other investigators labelled the disease as inactive/moderately active or active/very active. Univariate–multivariate linear regression analyses were used to define variables predicting the ‘gold standard’, their weight and derive an activity index. The cut-off point of the index best separating active/very active from inactive/moderately active disease was identified by a receiver-operating curve analysis. The index was validated on a second set of 60 charts assessed by three different investigators on a 0–10 scale and defined as inactive/moderately active or active/very active by other two investigators. One hundred and twenty-three were investigated for changes over time in the index and their relationships with those in the summed Medsger severity score (MSS). Results A weighted 10-point activity index was identified and validated: Δ-skin=1.5 (Δ=patient assessed worsening during the previous month), modified Rodnan skin score (mRss) >18=1.5, digital ulcers=1.5, tendon friction rubs=2.25, C-reactive protein >1 mg/dL=2.25 and diffusing capacity of the lung for CO (DLCO) % predicted <70%=1.0. A cut-off ≥2.5 was found to identify patients with active disease. Changes in the index paralleled those of MSS (p=0.0001). Conclusions A preliminarily revised SSc activity index has been developed and validated, providing a valuable tool for clinical practice and observational studies.

Vasoactive Therapy in Systemic Sclerosis: Real-life Therapeutic Practice in More Than 3000 Patients.

Objective. Vasculopathy is a key factor in the pathophysiology of systemic sclerosis (SSc) and the main cause for Raynaud phenomenon (RP), digital ulcers (DU), and/or pulmonary arterial hypertension (PAH). It is so far unknown how patients with SSc are treated with vasoactive agents in daily practice. To determine to which extent patients with SSc were treated with different vasoactive agents, we used data from the German Network for Systemic Scleroderma registry. Methods. The data of 3248 patients with SSc were analyzed. Results. Patients were treated with vasoactive drugs in 61.1% of cases (1984/3248). Of these, 47.6% received calcium channel inhibitors, followed by 34.2% treated with angiotensin-converting enzyme (ACE) inhibitors, 21.1% treated with intravenous (IV) prostanoids, 10.1% with pentoxifylline, 8.8% with angiotensin 1 receptor antagonists (AT1RA), 8.7% with endothelin 1 receptor antagonists (ET1RA), 4.1% with phosphodiesterase type 5 (PDE5) inhibitors, and 5.3% with others. Patients with RP received vasoactive therapy in 63.3% of cases, with DU in 70.1%, and with PAH in 78.2% of cases. Logistic regression analysis revealed that patients with PAH were significantly more often treated with PDE5 inhibitors and ET1RA, and those with DU with ET1RA and IV prostanoids. In addition, 41.8% of patients were treated with ACE inhibitors and/or AT1RA. Patients registered after 2009 received significantly more often ET1RA, AT1RA, and IV prostanoids compared with patients registered prior to 2005. Conclusion. These data clearly indicate that many patients with SSc do not yet receive sufficient vasoactive therapy. Further, in recent years, a marked change of treatment regimens can be observed.

Functional autoantibodies in systemic sclerosis.

Functional autoantibodies are an emerging field of research that focuses on the effects of these immunoglobulins when they bind to their target molecules. Accumulating information now exists about the molecular targets and precise binding mechanisms of functional autoantibodies as well as about their downstream effects. These data raise the need to distinguish functional autoantibodies from non-functional autoantibodies with regard to their ability to stimulate or to inhibit their target protein via binding. The presence of autoantibodies has been documented in autoimmune disorders decades ago, but meanwhile, more and more autoantibodies have been identified as functional, acting as pathogenic drivers involved in the induction of organ-specific damage in systemic sclerosis as well as in other autoimmune disorders. These findings offer new opportunities for the development of novel therapeutic strategies.

Monocytic Angiotensin and Endothelin Receptor Imbalance Modulate Secretion of the Profibrotic Chemokine Ligand 18

Objective. To assess monocytic expression and ratio of angiotensin and endothelin receptors in systemic sclerosis (SSc) and their functional relevance. Methods. Receptor expression was measured by flow cytometry. Chemokine ligand 18 (CCL18) concentration in supernatants of peripheral blood mononuclear cells stimulated with immunoglobulin G was measured by ELISA. Results. Monocytes of patients with SSc presented an increased angiotensin II Type 1 receptor (AT1R)/AT2R ratio compared with those of healthy donors. Patients with lung fibrosis and patients with high modified Rodnan skin score showed a reduced endothelin 1 Type A receptor (ETAR)/ETBR ratio. High AT1R/AT2R, but low ETAR/ETBR ratios corresponded to higher CCL18 secretion. Conclusion. Altered angiotensin and endothelin receptor ratios observed in SSc influence autoantibody-mediated effects such as secretion of profibrotic CCL18.

Prediction of progression of interstitial lung disease in patients with systemic sclerosis: the SPAR model

Objectives To identify the predictive clinical characteristics and establish a prediction model for the progression of mild interstitial lung disease (ILD) in patients with systemic sclerosis (SSc). Methods Patients with SSc from two independent prospective cohorts were included in this observational study. All patients fulfilled the 2013 American College of Rheumatology/European League Against Rheumatism criteria, had mild ILD at baseline diagnosed by High-Resolution Computed Tomography (HRCT), available baseline and ≥1 annual follow-up pulmonary function tests and no concomitant pulmonary hypertension or airflow obstruction. ILD progression was defined as a relative decrease in forced vital capacity (FVC)%≥15%, or FVC%≥10% combined with diffusing capacity for carbon monoxide %≥15% at 1-year follow-up. Candidate predictors for multivariate logistic regression were selected by expert opinion based on clinical significance. A prediction model for ILD progression was established in the derivation cohort and validated in the multinational validation cohort. Results A total of 25/98 and 25/117 patients with SSc showed ILD progression in the derivation cohort and the validation cohort, respectively. Lower SpO2 after 6 min walk test (6MWT) and arthritis ever were identified as independent predictors for ILD progression in both cohorts. The optimal cut-off value of SpO2 after 6MWT for predicting ILD progression was determined as 94% by receiver operating characteristic curve analysis. The derived SPAR model combining both predictors (SPO2 and ARthritis) increased the prediction rate from 25.5% to 91.7% with an area under the curve (95% CI) of 0.83 (0.73 to 0.93). Conclusions The evidence-based SPAR prediction model developed in our study might be helpful for the risk stratification of patients with mild SSc-ILD in clinical practice and cohort enrichment for future clinical trial design.

Systemic sclerosis associated interstitial lung disease - individualized immunosuppressive therapy and course of lung function: results of the EUSTAR group

BackgroundInterstitial lung disease in systemic sclerosis (SSc-ILD) is a major cause of SSc-related death. Imunosuppressive treatment (IS) is used in patients with SSc for various organ manifestations mainly to ameliorate progression of SSc-ILD. Data on everyday IS prescription patterns and clinical courses of lung function during and after therapy are scarce.MethodsWe analysed patients fulfilling American College of Rheumatology (ACR)/European League against Rheumatism (EULAR) 2013 criteria for SSc-ILD and at least one report of IS. Types of IS, pulmonary function tests (PFT) and PFT courses during IS treatment were evaluated.ResultsEUSTAR contains 3778/11,496 patients with SSc-ILD (33%), with IS in 2681/3,778 (71%). Glucocorticoid (GC) monotherapy was prescribed in 30.6% patients with GC combinations plus cyclophosphamide (CYC) (11.9%), azathioprine (AZA) (9.2%), methotrexate (MTX) (8.7%), or mycophenolate mofetil (MMF) (7.3%). Intensive IS (MMF + GC, CYC or CYC + GC) was started in patients with the worst PFTs and ground glass opacifications on imaging. Patients without IS showed slightly less worsening in forced vital capacity (FVC) when starting with FVC 50–75% or >75%. GC showed negative trends when starting with FVC <50%. Regarding diffusing capacity for carbon monoxide (DLCO), negative DLCO trends were found in patients with MMF.ConclusionsIS is broadly prescribed in SSc-ILD. Clusters of clinical and functional characteristics guide individualised treatment. Data favour distinguished decision-making, pointing to either watchful waiting and close monitoring in the early stages or start of immunosuppressive treatment in moderately impaired lung function. Advantages of specific IS are difficult to depict due to confounding by indication. Data do not support liberal use of GC in SSc-ILD.