Regulatory T Cells in Systemic Sclerosis

In recent years, accumulating evidence suggest that regulatory T cells (Tregs) are of paramount importance for the maintenance of immunological self-tolerance and immune homeostasis, even though they represent only about 5–10% of the peripheral CD4+ T cells in humans. Their key role is indeed supported by the spontaneous development of autoimmune diseases after Tregs depletion in mice. Moreover, there is also a growing literature that investigates possible contribution of Tregs numbers and activity in various autoimmune diseases. The contribution of Tregs in autoimmune disease has opened up a new therapeutic avenue based on restoring a healthy balance between Tregs and effector T-cells, such as Treg-based cellular transfer or low-dose IL-2 modulation. These therapies hold the promise of modulating the immune system without immunosuppression, while several issues regarding efficacy and safety need to be addressed. Systemic sclerosis (SSc) is an orphan connective tissue disease characterized by extensive immune abnormalities but also microvascular injury and fibrosis. Recently, data about the presence and function of Tregs in the pathogenesis of SSc have emerged although they remain scarce so far. First, there is a general agreement in the medical literature with regard to the decreased functional ability of circulating Tregs in SSc. Second the quantification of Tregs in patients have led to contradictory results; although the majority of the studies report reduced frequencies, there are conversely some indications suggesting that in case of disease activity circulating Tregs may increase. This paradoxical situation could be the result of a compensatory, but inefficient, amplification of Tregs in the context of inflammation. Nevertheless, these results must be tempered with regards to the heterogeneity of the studies for the phenotyping of the patients and of the most importance for Tregs definition and activity markers. Therefore, taking into account the appealing developments of Tregs roles in autoimmune diseases, together with preliminary data published in SSc, there is growing interest in deciphering Tregs in SSc, both in humans and mice models, to clarify whether the promises obtained in other autoimmune diseases may also apply to SSc

Acceptability, Feasibility, Drug Safety, and Effectiveness of a Pilot Mass Drug Administration with a Single Round of Sulfadoxine-Pyrimethamine Plus Primaquine and Indoor Residual Spraying in Communities with Malaria Transmission in Haiti, 2018.

For a malaria elimination strategy, Haiti's National Malaria Control Program piloted a mass drug administration (MDA) with indoor residual spraying (IRS) in 12 high-transmission areas across five communes after implementing community case management and strengthened surveillance. The MDA distributed sulfadoxine-pyrimethamine and single low-dose primaquine to eligible residents during house visits. The IRS campaign applied pirimiphos-methyl insecticide on walls of eligible houses. Pre- and post-campaign cross-sectional surveys were conducted to assess acceptability, feasibility, drug safety, and effectiveness of the combined interventions. Stated acceptability for MDA before the campaign was 99.2%; MDA coverage estimated at 10 weeks post-campaign was 89.6%. Similarly, stated acceptability of IRS at baseline was 99.9%; however, household IRS coverage was 48.9% because of the high number of ineligible houses. Effectiveness measured by Plasmodium falciparum prevalence at baseline and 10 weeks post-campaign were similar: 1.31% versus 1.43%, respectively. Prevalence of serological markers were similar at 10 weeks post-campaign compared with baseline, and increased at 6 months. No severe adverse events associated with the MDA were identified in the pilot; there were severe adverse events in a separate, subsequent campaign. Both MDA and IRS are acceptable and feasible interventions in Haiti. Although a significant impact of a single round of MDA/IRS on malaria transmission was not found using a standard pre- and post-intervention comparison, it is possible there was blunting of the peak transmission. Seasonal malaria transmission patterns, suboptimal IRS coverage, and low baseline parasitemia may have limited the effectiveness or the ability to measure effectiveness

Racial differences in systemic sclerosis disease presentation: a European Scleroderma Trials and Research group study

Objectives. Racial factors play a significant role in SSc. We evaluated differences in SSc presentations between white patients (WP), Asian patients (AP) and black patients (BP) and analysed the effects of geographical locations.Methods. SSc characteristics of patients from the EUSTAR cohort were cross-sectionally compared across racial groups using survival and multiple logistic regression analyses.Results. The study included 9162 WP, 341 AP and 181 BP. AP developed the first non-RP feature faster than WP but slower than BP. AP were less frequently anti-centromere (ACA; odds ratio (OR) = 0.4, P < 0.001) and more frequently anti-topoisomerase-I autoantibodies (ATA) positive (OR = 1.2, P = 0.068), while BP were less likely to be ACA and ATA positive than were WP [OR(ACA) = 0.3, P < 0.001; OR(ATA) = 0.5, P = 0.020]. AP had less often (OR = 0.7, P = 0.06) and BP more often (OR = 2.7, P < 0.001) diffuse skin involvement than had WP.AP and BP were more likely to have pulmonary hypertension [OR(AP) = 2.6, P < 0.001; OR(BP) = 2.7, P = 0.03 vs WP] and a reduced forced vital capacity [OR(AP) = 2.5, P < 0.001; OR(BP) = 2.4, P < 0.004] than were WP. AP more often had an impaired diffusing capacity of the lung than had BP and WP [OR(AP vs BP) = 1.9, P = 0.038; OR(AP vs WP) = 2.4, P < 0.001]. After RP onset, AP and BP had a higher hazard to die than had WP [hazard ratio (HR) (AP) = 1.6, P = 0.011; HR(BP) = 2.1, P < 0.001].Conclusion. Compared with WP, and mostly independent of geographical location, AP have a faster and earlier disease onset with high prevalences of ATA, pulmonary hypertension and forced vital capacity impairment and higher mortality. BP had the fastest disease onset, a high prevalence of diffuse skin involvement and nominally the highest mortality

Autoimmunity and systemic sclerosis : effects of regulatory T cells modulation in a mouse model

La sclérodermie systémique (ScS) est une maladie orpheline sévère, multi systémique. Elle est caractérisée par une microangiopathie, des phénomènes inflammatoire et immunologique et une fibrose tissulaire touchant la peau et les organes. Les complications pulmonaires sont aujourd'hui centrales dans le pronostic de la maladie. L'auto-immunité est un élément clé dans sa pathogénie. Cependant, les mécanismes et acteurs de ces dérégulations sont mal connus ce qui reste un frein au développement de l'immunothérapie. Des données convergentes suggèrent un rôle des lymphocytes T, dont les T régulateurs (Tregs) dans la pathogénie de la ScS, comme cela a été décrit dans d'autres maladies auto-immunes. Le modèle transgénique Fra-2 (Fra2ᵀᴳ) est un modèle murin caractérisé par une séquence pathogénique proche de la maladie humaine avec un rôle clé des désordres fibro-inflammatoires. Il représente une excellente opportunité pour étudier le rôle des dérèglements immunitaires dans la genèse des anomalies vasculaires et fibrosantes. Ainsi, les objectifs de ce travail ont été (i) d'évaluer le rôle des lymphocytes T CD4⁺, et plus spécifiquement des Tregs dans le modèle Fra2ᵀᴳ, et (ii) d'évaluer le compartiment des Tregs circulants ainsi que les différentes sous-populations d'effecteurs circulants chez les patients atteints de ScS. Nos résultats montrent une accumulation de cellules T CD4⁺ activées chez les souris Fra2ᵀᴳ, avec un biais Tₕ1/Tₕ2 intrinsèque, en faveur de la différentiation Tₕ2. Nous avons également observé un défaut de génération et de maturation thymique des Tregs, un défaut de sortie du thymus des Tregs matures et un défaut intrinsèque de différentiation périphérique en pTregs, conduisant à un déficit majeur des Tregs en périphérie. Une disponibilité périphérique réduite de l'Interleukine-2 (IL-2), due à une diminution de sa production par les cellules T CD4 conventionnelles, pourrait contribuer au défaut en Tregs. Cette hypothèse est confortée par la restauration de taux normaux de Tregs après un apport d'IL-2. Ce défaut préexistait à l'activation T et au développement du phénotype. Ces résultats nous ont conduit à évaluer des stratégies thérapeutiques visant à moduler les LTregs : il s'avère qu'à la fois un traitement par transfert adoptif néonatal de Tregs sauvages ou un traitement par IL-2 low-dose permettaient de corriger le phénotype pulmonaire des souris Fra2. Chez l'homme, nous avons observé une augmentation du pourcentage d'effecteurs activés, correspondant à une activation T, ainsi qu'une augmentation des proportions de cellules Tₕ17 et TFH. Nous n'avons pas mis en évidence de défaut quantitatif de Tregs circulants chez les patients atteints de ScS mais l'analyse du ratio entre effecteurs activés et Tregs activés montrait une augmentation du ratio chez les patients, pouvant aller dans le sens d'un défaut de régulation chez les malades. Nos résultats confortent une activation T dans la ScS pouvant être favorisée par un défaut en Tregs. Dans le modèle murin le plus proche de la maladie, à la fois un transfert adoptif de Tregs sauvages ou un traitement par IL-2 corrigeaient le phénotype des souris Fra2ᵀᴳ. Ainsi, nos résultats suggèrent qu'une immunothérapie modulant les Tregs pourrait être pertinente dans la ScS. Une intervention sous la forme d'injection d'IL-2 low-dose, comme cela est déjà proposé dans d'autres maladies auto-immunes, apparaît comme la modalité la plus adaptée à des développements futurs.Systemic sclerosis (SSc) is a severe, multi-systemic orphan disease. It is characterized by microvascular injury, inflammatory and immunological disturbances that culminate in skin and internal organ fibrosis. Nowadays, pulmonary complications are central to the prognosis of the disease. Autoimmunity is a hallmark of the pathogenesis. However, the pathomechanisms and key actors are not fully understood, which remains a limitation to the development of efficient immunotherapy. Converging data suggest a key role of T lymphocytes, including regulatory T lymphocytes (Tregs) in the pathogenesis of SSc as described in other autoimmune diseases. The Fra-2 transgenic mouse model (Fra2ᵀᴳ) is characterized by a pathogenic sequence close to human disease with a key role of fibro-inflammatory disturbances. This model represents an excellent opportunity to study the role of immune changes in the promotion and perpetuation of vascular and tissular fibrosing abnormalities. Thus, the aims of this work were (i) to evaluate the role of CD4⁺ T lymphocytes, and more specifically of Tregs in the Fra2ᵀᴳ model, and (ii) to evaluate the compartment of circulating Tregs as well as the different sub-populations of circulating effectors in patients with SSc. Our results show a striking accumulation of activated CD4⁺ T cells in Fra2ᵀᴳ mice, with an intrinsic Tₕ1/Tₕ2 bias for the benefit of Tₕ2 differentiation. We also observed a defect in the thymic generation and maturation of Tregs, a defect in the thymus egress of mature Tregs and an intrinsic defect in peripheral differentiation into pTregs, leading to a major deficit of Tregs in the periphery. Reduced peripheral availability of Interleukin-2 (IL-2), due to a decrease in its production by conventional CD4 T cells, could contribute to the Tregs defect. This hypothesis is supported by the restoration of normal Tregs levels after IL-2 supplementation. This defect occurs ahead of T activation and phenotype development. These results have led us to evaluate therapeutic strategies aiming at modulating Tregs: it appears that both a treatment by neonatal adoptive transfer of wild-type Tregs or a treatment with low-dose IL-2 or a combination of both allowed us to minimize the mouse phenotype and reduce significantly Fra2ᵀᴳ mice lung damages. In humans, we observed an increase in the percentage of activated effectors, corresponding to an activation of T cells, as well as an increase in the proportions of Tₕ17 and TFH cells. We did not identify any quantitative defect of circulating Tregs in SSc patients, but ratio between activated effectors and activated Tregs was increased supporting a regulatory defect in SSc. Altogether, our results support a T cell activation in SSc that can be related to a Tregs default. In the mouse model which is the closest to the human disease, restoring Treg cells was efficient to reduce the lung damages that characterize Fra2ᵀᴳ mice. Thus, our results suggest that Tregs-modulating immunotherapy could be relevant in SSc and deserves to be followed-up. An intervention by using low-dose IL-2 injection, as currently proposed in other autoimmune diseases, appears to be the most suitable strategy for future developments

Soluble CD163 as a Potential Biomarker in Systemic Sclerosis

Objective. To evaluate the performance of serum and urinary sCD163 concentrations as possible biomarker in systemic sclerosis (SSc). Methods. Urine and serum samples were obtained from SSc patients and age- and sex-matched controls. Serum and urinary sCD163 concentrations were measured by commercially available ELISA kit. SSc patients were assessed following international guidelines. Cross-sectional analyses were performed. Results. Two hundred and three SSc patients were included. The control group consisted of 47 age- and sex-matched patients having noninflammatory diseases, mainly osteoporosis. Serum sCD163 levels were significantly higher in SSc patients compared with controls (mean ± SD: 529 ± 251 versus 385 ± 153 ng/mL; p<0.001). Urinary sCD163 concentrations were higher in SSc patients than controls, but this did not reach significance (236 ± 498 versus 176 ± 173 ng/mg uCr; p=0.580). The sCD163 concentrations were not associated with clinical, laboratory, and instrumental characteristics of SSc patients. Conclusion. To our knowledge, this is the first evaluation of both serum and urinary sCD163 levels in SSc. Our results show a significant difference for sera values that should be prioritized for further studies as compared to urinary measurements. Our results further support that the M2 macrophages/CD163 signaling system may play a role in the pathogenesis of SSc, although we could not identify a subset of SSc patients with higher concentrations

Soluble CD163 as a Potential Biomarker in Systemic Sclerosis

Objective. To evaluate the performance of serum and urinary sCD163 concentrations as possible biomarker in systemic sclerosis (SSc). Methods. Urine and serum samples were obtained from SSc patients and age- and sex-matched controls. Serum and urinary sCD163 concentrations were measured by commercially available ELISA kit. SSc patients were assessed following international guidelines. Cross-sectional analyses were performed. Results. Two hundred and three SSc patients were included. The control group consisted of 47 age- and sex-matched patients having noninflammatory diseases, mainly osteoporosis. Serum sCD163 levels were significantly higher in SSc patients compared with controls (mean ± SD: 529 ± 251 versus 385 ± 153 ng/mL; p<0.001). Urinary sCD163 concentrations were higher in SSc patients than controls, but this did not reach significance (236 ± 498 versus 176 ± 173 ng/mg uCr; p=0.580). The sCD163 concentrations were not associated with clinical, laboratory, and instrumental characteristics of SSc patients. Conclusion. To our knowledge, this is the first evaluation of both serum and urinary sCD163 levels in SSc. Our results show a significant difference for sera values that should be prioritized for further studies as compared to urinary measurements. Our results further support that the M2 macrophages/CD163 signaling system may play a role in the pathogenesis of SSc, although we could not identify a subset of SSc patients with higher concentrations

Combined effect of genetic background and gender in a mouse model of bleomycin-induced skin fibrosis

International audienceSystemic sclerosis (SSc) is a connective tissue disorder characterised by the development of skin fibrosis. Our current understanding of the disease pathogenesis is incomplete and the study of SSc is hindered, at least partially, by a lack of animal models that fully replicate the complex state of human disease. Murine model of bleomycin-induced dermal fibrosis encapsulates important events that take place early in the disease course.METHODS:To characterise the optimum in vivo parameters required for the successful induction of dermal fibrosis we subjected three commonly used mouse strains to repeated subcutaneous bleomycin injections. We aimed to identify the effects of genetic background and gender on the severity of skin fibrosis. We used male and female Balb/C, C57BL/6, and DBA/2 strains and assessed their susceptibility to bleomycin-induced fibrosis by measuring dermal thickness, hydroxyproline/collagen content and number of resident myofibroblasts, all of which are important indicators of the severity of skin fibrosis. All data are expressed as mean values ± SEM. The Mann-Whitney U test was used for statistical analysis with GraphPad Prism 6.04 software.RESULTS:Dermal fibrosis was most severe in Balb/C mice compared to C57BL/6 and DBA/2 suggesting that Balb/C mice are more susceptible to bleomycin-induced fibrosis. Analysis of the effect of gender on the severity of fibrosis showed that male Balb/C, C57BL/6, DBA/2 mice had a tendency to develop more pronounced fibrosis phenotype than female mice. Of potential importance, male Balb/C mice developed the most severe fibrosis phenotype compared to male C57BL/6 and male DBA/2 as indicated by significantly increased number of dermal myofibroblasts.CONCLUSION:Our study highlights the importance of genetic background and gender in the induction of murine dermal fibrosis. Robust and reproducible animal models of fibrosis are important research tools used in pharmacological studies which may lead to better understanding of the pathogenesis of fibrotic diseases and assist in identification of new drugs

Impaired quality of life in systemic sclerosis and patient perception of the disease: A large international survey

OBJECTIVES: The purpose of this study was to assess health-related quality of life (HRQoL) and disease perception in a large, international group of patients with systemic sclerosis (SSc). METHODS: We placed a standardized questionnaire on a website for patient access. Socio-demographic information, disease characteristics, and self-assessment questionnaires-the Short Form 36 (SF-36) and the Revised Illness Perception Questionnaire (IPQ-R)-were collected. RESULTS: A total of 1902 patients from 60 countries were included. HRQoL appeared to be impaired in SSc, particularly for physical health (PCS, mean ± SD = 43.4 ± 23.4). SSc patients also had strong perceptions about the chronic nature and negative consequence of the disease, and experienced negative emotions due to SSc. Patients with diffuse cutaneous SSc had a poorer HRQoL than those with limited cutaneous SSc, for both physical (PCS, mean ± SD = 46.6 ± 23.7 vs. 39.8 ± 22.3; p < 0.0001) and mental components (MCS, mean ± SD = 53.8 ± 23.0 vs. 50.3 ± 23.2; p = 0.003). Late-stage SSc patients were more likely to perceive their disease chronic (p < 0.0001), less controllable (p = 0.03) and with more consequences (p = 0.008), but they had a better understanding of their disease and experienced fewer negative emotions. Raynaud's phenomenon and gastrointestinal complications were the organ involvements with the greatest impact on QoL, they were the two variables associated with the most negative perception of illness severity. CONCLUSION: This study, performed on the largest group ever set up for this purpose, confirms the major impact on QoL and the negative perceptions of their disease expressed by SSc patients. However, the perception of this illness tended to improve with disease duration, suggesting that patients find effective coping strategies

IL ‐2‐related regulatory CD4 T‐cell deficiency leads to the development of lung fibrosis and vascular remodeling

International audienceObjectives: Systemic sclerosis (SSc) is a dreadful autoimmune disease characterized by severe lung outcomes reducing life expectancy. Fra2TG mice offer the opportunity to decipher the relationships between the immune system and lung fibrosis. We herein investigated whether Fra2TG mice lung phenotype could result from an imbalance between the effector and the regulatory arms of the CD4 T-cell compartment.Methods: The homeostasis and phenotype of peripheral CD4 T cells from Fra2TG and control mice were first extensively characterized by multicolor flow cytometry. Then, different cures aimed at restoring regulatory CD4 T-cell (Treg) homeostasis have been tested, including adoptive transfer of Treg cells and treatment with low-dose IL-2.Results: Fra2TG mice exhibited a marked decrease in the proportion and absolute number of peripheral Treg cells which precedes the accumulation of activated, TH 2-polarized, CD4 T cells. This defect in Treg-cell homeostasis derived from combined mechanisms including an impaired generation of these cells in both the thymus and the periphery. The impaired ability of peripheral conventional CD4 T cells to produce IL-2 may greatly participate to Treg-cell deficiency in Fra2TG mice. Remarkably, adoptive transfer of Tregs, low-dose IL-2 therapy or combination of both all corrected the phenotype of Fra2TG mice, with a significant reduction in pulmonary parenchymal fibrosis and lung vascular remodeling.Conclusion: Immunotherapies aiming at restoring Treg-cell homeostasis could be relevant in SSc. An intervention based on low-dose IL-2 injections, as already proposed in other autoimmune diseases, could be the most suitable modality for future developments