Consensus statement on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: Localized scleroderma, systemic sclerosis and overlap syndromes.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present consensus provides an update to the 2017 European Dermatology Forum Guidelines, focusing on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, updated strategies for the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this consensus provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes.

Tocilizumab in COVID-19 interstitial pneumonia.

BACKGROUND: Published reports on tocilizumab in COVID-19 pneumonitis show conflicting results due to weak designs or heterogeneity in critical methodological issues. METHODS: This open-label trial, structured according to Simon's optimal design, aims to identify factors predicting which patients could benefit from anti-IL6 strategies and to enhance the design of unequivocal and reliable future randomized trials. A total of 46 patients with COVID-19 pneumonia needing of oxygen therapy to maintain SO2 > 93% and with recent worsening of lung function received a single infusion of tocilizumab. Clinical and biological markers were measured to test their predictive values. Primary end point was early and sustained clinical response. RESULTS: Twenty-one patients fulfilled pre-defined response criteria. Lower levels of IL-6 at 24 h after tocilizumab infusion (P = 0.049) and higher baseline values of PaO2/FiO2 (P = 0.008) predicted a favourable response. CONCLUSIONS: Objective clinical response rate overcame the pre-defined threshold of 30%. Efficacy of tocilizumab to improve respiratory function in patients selected according to our inclusion criteria warrants investigations in randomized trials.

Identifying research questions for HIV, tuberculosis, tuberculosis-HIV, malaria, and neglected tropical diseases through the World Health Organization guideline development process: a retrospective analysis, 2008-2018.

OBJECTIVES: World Health Organization (WHO) guidelines for health programmes and healthcare delivery are the foundation of its technical leadership in public health and essential to decision-making globally. A key function of guideline development is to identify areas in which further evidence is needed because filling these gaps will lead to future improvements in population health. The objective of this study was to examine the knowledge gaps and research questions for addressing those gaps generated through the WHO guideline development process, with the goal of informing future strategies for improving and strengthening the guideline development process. STUDY DESIGN: We did a systematic, retrospective analysis of research questions identified in the published guidelines. METHODS: We analyzed guidelines published between January 1, 2008, and December 31, 2018, by the Communicable Diseases Cluster in five disease areas: tuberculosis (TB), HIV, malaria, TB-HIV, and neglected tropical diseases (NTDs). Research questions were extracted independently by two researchers. We analyzed the distribution of research questions by disease and by topic category and did a qualitative assessment of optimum practice for research question generation during the guideline development process. RESULTS: A total of 48 guidelines were included: 26 on HIV, 1 on malaria, 11 on TB, 5 on TB/HIV, and 5 on NTDs. Overall, 36 (75%) guidelines encompassed a total of 360 explicit research questions; the remainder did not contain specific research questions. The number of research questions that focused on TB was 49, TB/HIV was 38, HIV was 250, and NTDs was 23. The number of research questions that focused on diagnosis was 43 (11.9%) of 360, prevention was 62 (17.2%), treatment was 103 (28.6%), good practice was 12 (3.3%), service delivery was 86 (23.8%), and other areas was 54 (15%). Research questions were often not formulated in a specific or actionable way and were hard to identify in the guideline. Examples of good practice identified by the review team involved the generation of specific and narrowly defined research questions, with accompanying recommendations for appropriate study design. CONCLUSIONS: The WHO must strengthen its approach to identifying and presenting research questions during the guideline development process. Ensuring access to research questions is a key next step in adding value to the guideline development process.

There is a need for new systemic sclerosis subset criteria. A content analytic approach.

OBJECTIVES: Systemic sclerosis (SSc) is heterogenous. The objectives of this study were to evaluate the purpose, strengths and limitations of existing SSc subset criteria, and identify ideas among experts about subsets. METHODS: We conducted semi-structured interviews with randomly sampled international SSc experts. The interview transcripts underwent an iterative process with text deconstructed to single thought units until a saturated conceptual framework with coding was achieved and respondent occurrence tabulated. Serial cross-referential analyses of clusters were developed. RESULTS: Thirty experts from 13 countries were included; 67% were male, 63% were from Europe and 37% from North America; median experience of 22.5 years, with a median of 55 new SSc patients annually. Three thematic clusters regarding subsetting were identified: research and communication; management; and prognosis (prediction of internal organ involvement, survival). The strength of the limited/diffuse system was its ease of use, however 10% stated this system had marginal value. Shortcomings of the diffuse/limited classification were the risk of misclassification, predictions/generalizations did not always hold true, and that the elbow or knee threshold was arbitrary. Eighty-seven percent use more than 2 subsets including: SSc sine scleroderma, overlap conditions, antibody-determined subsets, speed of progression, and age of onset (juvenile, elderly). CONCLUSIONS: We have synthesized an international view of the construct of SSc subsets in the modern era. We found a number of factors underlying the construct of SSc subsets. Considerations for the next phase include rate of change and hierarchal clustering (e.g. limited/diffuse, then by antibodies).

European dermatology forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 2: Scleromyxedema, scleredema and nephrogenic systemic fibrosis.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 2 of this guideline provides clinicians with an overview of the diagnosis and treatment of scleromyxedema, scleredema (of Buschke) and nephrogenic systemic sclerosis (nephrogenic fibrosing dermopathy).

European Dermatology Forum S1-guideline on the diagnosis and treatment of sclerosing diseases of the skin, Part 1: localized scleroderma, systemic sclerosis and overlap syndromes.

The term 'sclerosing diseases of the skin' comprises specific dermatological entities, which have fibrotic changes of the skin in common. These diseases mostly manifest in different clinical subtypes according to cutaneous and extracutaneous involvement and can sometimes be difficult to distinguish from each other. The present guideline focuses on characteristic clinical and histopathological features, diagnostic scores and the serum autoantibodies most useful for differential diagnosis. In addition, current strategies in the first- and advanced-line therapy of sclerosing skin diseases are addressed in detail. Part 1 of this guideline provides clinicians with an overview of the diagnosis and treatment of localized scleroderma (morphea), and systemic sclerosis including overlap syndromes of systemic sclerosis with diseases of the rheumatological spectrum.

[Atypical scurvy associated with anorexia nervosa]. / Scorbut atypique associé à une anorexie mentale.

INTRODUCTION: Scurvy, or "Barlow's disease", is a widely described disease involving cutaneous and mucosal lesions resulting from vitamin C deficiency. Herein, we report a case of scurvy in a 48-year-old woman that was unusual in its atypical cutaneous-mucosal presentation as well as its association with anorexia nervosa. PATIENTS AND METHODS: A 48-year-old woman treated for depression for several years was admitted to hospital for her impaired general state of health. Over the last year, she had presented palmoplantar rash and episodes of perimalleolar oedema. The clinical examination showed the patient to have wasting syndrome, with a BMI of 11.9kg/m2, lower-limb oedema, palmoplantar fissures, geographic tongue, telogen effluvium and purpuric petechiae on her right knee. However, no gingival bleeding was noted and there was no loss of tooth enamel. The remainder of the clinical examination was normal. Blood tests revealed extremely low vitamin C levels without any other associated deficiencies, as well as laboratory signs of cytolysis and anicteric cholestasis without inflammatory syndrome. The diagnosis of anorexia nervosa was made by psychiatrists, despite the unusual age of onset. Favorable clinical outcome was rapidly achieved via a one-month course of vitamin C supplements at a daily dose of 1g. DISCUSSION: The absence of classical buccal-dental symptoms and the presence of keratotic dermatosis with fissures and ulcers on the hands and feet are atypical in scurvy; however, this diagnosis was confirmed by the existence of purpura evoking capillary fragility, the patient's drastically low vitamin C level and the rapid subsidence of symptoms following treatment with oral vitamin C alone. Anorexia nervosa was doubtless the cause of deficiency. This situation is rare and a systematic review of the literature in Medline via PubMed showed that only three reports of scurvy associated with mental anorexia have been published since 1975.

Recommendations for the management of biofilm: a consensus document.

The potential impact of biofilm on healing in acute and chronic wounds is one of the most controversial current issues in wound care. A significant amount of laboratory-based research has been carried out on this topic, however, in 2013 the European Wound Management Association (EWMA) pointed out the lack of guidance for managing biofilms in clinical practice and solicited the need for guidelines and further clinical research. In response to this challenge, the Italian Nursing Wound Healing Society (AISLeC) initiated a project which aimed to achieve consensus among a multidisciplinary and multiprofessional international panel of experts to identify what could be considered part of 'good clinical practice' with respect to the recognition and management of biofilms in acute and chronic wounds. The group followed a systematic approach, developed by the GRADE working group, to define relevant questions and clinical recommendations raised in clinical practice. An independent librarian retrieved and screened approximately 2000 pertinent published papers to produce tables of levels of evidence. After a smaller focus group had a multistep structured discussion, and a formal voting process had been completed, ten therapeutic interventions were identified as being strongly recommendable for clinical practice, while another four recommendations were graded as being 'weak'. The panel subsequently formulated a preliminary statement (although with a weak grade of agreement): 'provided that other causes that prevent optimal wound healing have been ruled out, chronic wounds are chronically infected'. All members of the panel agreed that there is a paucity of reliable, well-conducted clinical trials which have produced clear evidence related to the effects of biofilm presence. In the meantime it was agreed that expert-based guidelines were needed to be developed for the recognition and management of biofilms in wounds and for the best design of future clinical trials. This is a fundamental and urgent task for both laboratory-based scientists and clinicians.

Fast readout architectures for large arrays of digital pixels: examples and applications.

Modern pixel detectors, particularly those designed and constructed for applications and experiments for high-energy physics, are commonly built implementing general readout architectures, not specifically optimized in terms of speed. High-energy physics experiments use bidimensional matrices of sensitive elements located on a silicon die. Sensors are read out via other integrated circuits bump bonded over the sensor dies. The speed of the readout electronics can significantly increase the overall performance of the system, and so here novel forms of readout architectures are studied and described. These circuits have been investigated in terms of speed and are particularly suited for large monolithic, low-pitch pixel detectors. The idea is to have a small simple structure that may be expanded to fit large matrices without affecting the layout complexity of the chip, while maintaining a reasonably high readout speed. The solutions might be applied to devices for applications not only in physics but also to general-purpose pixel detectors whenever online fast data sparsification is required. The paper presents also simulations on the efficiencies of the systems as proof of concept for the proposed ideas.

Non-markovian models of blocking in concurrent and countercurrent flows.

We investigate models in which blocking can interrupt a particulate flow process at any time. Filtration, and flow in micro or nanochannels and traffic flow are examples of such processes. We first consider concurrent flow models where particles enter a channel randomly. If at any time two particles are simultaneously present in the channel, failure occurs. The key quantities are the survival probability and the distribution of the number of particles that pass before failure. We then consider a counterflow model with two opposing Poisson streams. There is no restriction on the number of particles passing in the same direction, but blockage occurs if, at any time, two opposing particles are simultaneously present in the passage.

A randomized controlled trial of rituximab for the treatment of severe cryoglobulinemic vasculitis.

OBJECTIVE: To conduct a long-term, prospective, randomized controlled trial evaluating rituximab (RTX) therapy for severe mixed cryoglobulinemia or cryoglobulinemic vasculitis (CV). METHODS: Fifty-nine patients with CV and related skin ulcers, active glomerulonephritis, or refractory peripheral neuropathy were enrolled. In CV patients who also had hepatitis C virus (HCV) infection, treatment of the HCV infection with antiviral agents had previously failed or was not indicated. Patients were randomized to the non-RTX group (to receive conventional treatment, consisting of 1 of the following 3: glucocorticoids; azathioprine or cyclophosphamide; or plasmapheresis) or the RTX group (to receive 2 infusions of 1 gm each, with a lowering of the glucocorticoid dosage when possible, and with a second course of RTX at relapse). Patients in the non-RTX group who did not respond to treatment could be switched to the RTX group. Study duration was 24 months. RESULTS: Survival of treatment at 12 months (i.e., the proportion of patients who continued taking their initial therapy), the primary end point, was statistically higher in the RTX group (64.3% versus 3.5% [P < 0.0001]), as well as at 3 months (92.9% versus 13.8% [P < 0.0001]), 6 months (71.4% versus 3.5% [P < 0.0001]), and 24 months (60.7% versus 3.5% [P < 0.0001]). The Birmingham Vasculitis Activity Score decreased only after treatment with RTX (from a mean ± SD of 11.9 ± 5.4 at baseline to 7.1 ± 5.7 at month 2; P < 0.001) up to month 24 (4.4 ± 4.6; P < 0.0001). RTX appeared to be superior therapy for all 3 target organ manifestations, and it was as effective as conventional therapy. The median duration of response to RTX was 18 months. Overall, RTX treatment was well tolerated. CONCLUSION: RTX monotherapy represents a very good option for severe CV and can be maintained over the long term in most patients.

Alterations of ROS pathways in scleroderma begin at stem cell level.

Scleroderma is a chronic systemic autoimmune disease (primarily of the skin) characterized by fibrosis (or hardening), vascular alterations and autoantibodies production.There are currently no effective therapies against this devastating and often lethal disorder. Despite the interest for the immunomodulatory effects of mesenchymal stem cells (MSCs) in autoimmune diseases, the role of MSCs in scleroderma is still unknown. A pivotal role in scleroderma onset is played by oxidative stress associated with the accumulation of great amounts of reactive oxygen species (ROS). This study depicts some phenotypic and functional features of MSCs isolated from the skin of healthy and scleroderma patients; the ROS production and accumulation, the expression of ERK1/2 and the effects of the stimulation with PDGF, were analyzed in MSCs; results were compared to those observed in primary fibroblasts (Fbs) isolated from the same subjects. We found that the pro-oxidant environment exerted by scleroderma affects MSCs, which are still able to counteract the ROS accumulation by improving the antioxidant defenses. On the contrary, scleroderma fibroblasts show a disruption of these mechanisms, with consequent ROS increase and the activation of the cascade triggered by scleroderma auto-antibodies against PDGFR.

Increased expression of the ectoenzyme CD38 in peripheral blood plasmablasts and plasma cells of patients with systemic sclerosis.

Objective: CD38 is a type II glycoprotein highly expressed on plasmablasts and on short- and long-lived plasma cells, but weakly expressed by lymphoid, myeloid, and non-hematopoietic cells. CD38 is a target for therapies aimed at depleting antibody-producing plasma cells. Systemic sclerosis (SSc) is an immune-mediated disease with a well-documented pathogenic role of B cells. We therefore analyzed CD38 expression in different subsets of peripheral blood mononuclear cells (PBMCs) from a cohort of SSc patients. Methods: Cell surface expression of CD38 was evaluated on PBMCs from SSc patients using eight-color flow cytometry analysis performed with a FacsCanto II (BD). Healthy individuals were used as controls (HC). Results: Forty-six SSc patients (mean age 56, range 23-79 years; 38 females and 8 males), and thirty-two age- and sex-matched HC were studied. Twenty-eight patients had the limited cutaneous form and eighteen the diffuse cutaneous form of SSc. The mean disease duration was 7 years. Fourteen patients were on immunosuppressive therapy (14 MMF, 5 RTX). The total percentages of T, B and NK cells were not different between SSc and HC. Compared to HC, SSc patients had higher levels of CD3+CD38+ T cells (p<0.05), higher percentage (p<0.001) of CD3+CD4+CD25+FOXP3+ regulatory T cells, lower percentage (p<0.05) of CD3+CD56+ NK T cells. Moreover, SSc patients had higher levels of CD24highCD19+CD38high regulatory B cells than HC (p<0.01), while the amount of CD24+CD19+CD38+CD27+ memory B cells was lower (p<0.001). Finally, the percentages of circulating CD38highCD27+ plasmablasts and CD138+CD38high plasma cells were both higher in the SSc group than in HC (p<0.001). We did not observe any correlations between these immunophenotypes and disease subsets or duration, and ongoing immunosuppressive treatment. Conclusions: The increased expression of CD38 in peripheral blood plasmablasts and plasma cells of SSc patients may suggest this ectoenzyme as a candidate therapeutic target, under the hypothesis that depletion of these cells may beneficially downregulate the chronic immune response in SSc patients. Validation of this data in multicenter cohorts shall be obtained prior to clinical trials with existing anti-CD38 drugs.

Toxicity of spike fragments SARS-CoV-2 S protein for zebrafish: A tool to study its hazardous for human health?

Despite the significant increase in the generation of SARS-CoV-2 contaminated domestic and hospital wastewater, little is known about the ecotoxicological effects of the virus or its structural components in freshwater vertebrates. In this context, this study evaluated the deleterious effects caused by SARS-CoV-2 Spike protein on the health of Danio rerio, zebrafish. We demonstrated, for the first time, that zebrafish injected with fragment 16 to 165 (rSpike), which corresponds to the N-terminal portion of the protein, presented mortalities and adverse effects on liver, kidney, ovary and brain tissues. The conserved genetic homology between zebrafish and humans might be one of the reasons for the intense toxic effects followed inflammatory reaction from the immune system of zebrafish to rSpike which provoked damage to organs in a similar pattern as happen in severe cases of COVID-19 in humans, and, resulted in 78,6% of survival rate in female adults during the first seven days. The application of spike protein in zebrafish was highly toxic that is suitable for future studies to gather valuable information about ecotoxicological impacts, as well as vaccine responses and therapeutic approaches in human medicine. Therefore, besides representing an important tool to assess the harmful effects of SARS-CoV-2 in the aquatic environment, we present the zebrafish as an animal model for translational COVID-19 research.

Clinical prediction of 5-year survival in systemic sclerosis: validation of a simple prognostic model in EUSTAR centres.

OBJECTIVE: Systemic sclerosis (SSc) is associated with a significant reduction in life expectancy. A simple prognostic model to predict 5-year survival in SSc was developed in 1999 in 280 patients, but it has not been validated in other patients. The predictions of a prognostic model are usually less accurate in other patients, especially from other centres or countries. A study was undertaken to validate the prognostic model to predict 5-year survival in SSc in other centres throughout Europe. METHODS: A European multicentre cohort of patients with SSc diagnosed before 2002 was established. Patients with SSc according to the preliminary American College of Rheumatology classification criteria were eligible for the study when they were followed for at least 5 years or shorter if they died. The primary outcome was 5-year survival after diagnosis of SSc. The predefined prognostic model uses the following baseline variables: age, gender, presence of urine protein, erythrocyte sedimentation rate (ESR) and carbon monoxide diffusing capacity (DLCO). RESULTS: Data were available for 1049 patients, 119 (11%) of whom died within 5 years after diagnosis. Of the patients, 85% were female, the mean (SD) age at diagnosis was 50 (14) years and 30% were classified as having diffuse cutaneous SSc. The prognostic model with age (OR 1.03), male gender (OR 1.93), urine protein (OR 2.29), elevated ESR (1.89) and low DLCO (OR 1.94) had an area under the receiver operating characteristic curve of 0.78. Death occurred in 12 (2.2%) of 509 patients with no risk factors, 45 (13%) of 349 patients with one risk factor, 55 (33%) of 168 patients with two risk factors and 7 (30%) of 23 patients with three risk factors. CONCLUSION: A simple prognostic model using three disease factors to predict 5-year survival at diagnosis in SSc showed reasonable performance upon validation in a European multicentre study.

Preliminary classification criteria for the cryoglobulinaemic vasculitis.

BACKGROUND: To develop preliminary classification criteria for the cryoglobulinaemic syndrome or cryoglobulinaemic vasculitis (CV). METHODS: Study part I developed a questionnaire for CV to be included in the formal, second part (study part II). Positivity of serum cryoglobulins was defined by experts as an essential condition for CV classification. In study part II, a core set of classification items (questionnaire, clinical and laboratory items, as agreed) was tested in three groups of patients and controls-that is, group A (new patients with the CV), group B (controls with serum cryoglobulins but lacking CV) and group C (controls without serum cryoglobulins but with features which can be observed in CV). RESULTS: In study part I (188 cases, 284 controls), a positive response to at least two of three selected questions showed a sensitivity of 81.9% and a specificity of 83.5% for CV. This questionnaire was employed and validated in study part II, which included 272 patients in group A and 228 controls in group B. The final classification criteria for CV, by pooling data from group A and group B, required the positivity of questionnaire plus clinical, questionnaire plus laboratory, or clinical plus laboratory items, or all the three, providing a sensitivity of 88.5% and a specificity of 93.6% for CV. By comparing data in group A versus group C (425 controls), the same classification criteria showed a sensitivity 88.5% and a specificity 97.0% for CV. CONCLUSION: Classification criteria for CV were developed, and now need validation.

Anisotropic anomalous diffusion assessed in the human brain by scalar invariant indices.

A new method to investigate anomalous diffusion in human brain, inspired by the stretched-exponential model proposed by Hall and Barrick, is proposed here, together with a discussion about its potential application to cerebral white matter characterization. Aim of the work was to show the ability of anomalous diffusion indices to characterize white matter structures, whose complexity is only partially accounted by diffusion tensor imaging indices. MR signal was expressed as a stretched-exponential only along the principal axes of diffusion; whereas, in a generic direction, it was modeled as a combination of three stretched-exponentials. Indices to quantify the tissue anomalous diffusion and its anisotropy, independently of the experiment reference frame, were derived. Experimental results, obtained on 10 healthy subjects at 3T, show that the new parameters are highly correlated to intrinsic local geometry when compared with Hall and Barrick indices. Moreover, they offer a different contrast in white matter regions when compared with diffusion tensor imaging. Specifically, the new indices show a higher capability to discriminate among areas of the corpus callosum associated to different distribution in axonal densities, thus offering a new potential tool to detect more specific patterns of brain abnormalities than diffusion tensor imaging in the presence of neurological and psychiatric disorders.

Population genetics of Schistosoma haematobium: development of novel microsatellite markers and their application to schistosomiasis control in Mali.

The recent implementation of mass drug administration (MDA) for control of uro-genital schistosomiasis has identified an urgent need for molecular markers to both directly monitor the impact of MDA, for example to distinguish re-infections from uncleared infections, as well as understand aspects of parasite reproduction and gene flow which might predict evolutionary change, such as the development and spread of drug resistance. We report the development of a novel microsatellite tool-kit allowing, for the first time, robust genetic analysis of individual S. haematobium larvae collected directly from infected human hosts. We genotyped the parasite populations of 47 children from 2 schools in the Ségou region of Mali, the first microsatellite study of this highly neglected parasite. There was only limited evidence of population subdivision between individual children or between the two schools, suggesting that few barriers to gene flow exist in this population. Complex relationships between parasite reproductive success, infection intensity and host age and gender were identified. Older children and boys harboured more diverse infections, as measured by the number of unique adult genotypes present. Individual parasite genotypes had variable reproductive success both across hosts, a pre-requisite for evolutionary selection, and, phenotypically, in hosts of different ages and genders. These data serve as a baseline against which to measure the effect of treatment on parasite population genetics in this region of Mali, and the tools developed are suitable to further investigate this important pathogen, and its close relatives, throughout their range.

Spatio-temporal anomalous diffusion in heterogeneous media by nuclear magnetic resonance.

In this paper, we describe nuclear magnetic resonance measurements of water diffusion in highly confined and heterogeneous colloidal systems using an anomalous diffusion model. For the first time, temporal and spatial fractional exponents, α and µ, introduced within the framework of continuous time random walk, are simultaneously measured by pulsed gradient spin-echo NMR technique in samples of micro-beads dispersed in aqueous solution. In order to mimic media with low and high level of disorder, mono-dispersed and poly-dispersed samples are used. We find that the exponent α depends on the disorder degree of the system. Conversely, the exponent µ depends on both bead sizes and magnetic susceptibility differences within samples. The new procedure proposed here may be a useful tool to probe porous materials and microstructural features of biological tissue.

Quasistationary states and the range of pair interactions.

"Quasistationary" states are approximately time independent out of equilibrium states which have been observed in a variety of systems of particles interacting by long-range interactions. We investigate here the conditions of their occurrence for a generic pair interaction V(r→∞)~1/r(γ) with γ>0, in d>1 dimensions. We generalize analytic calculations known for gravity in d=3 to determine the scaling parametric dependences of their relaxation rates due to two-body collisions, and report extensive numerical simulations testing their validity. Our results lead to the conclusion that, for γd-1 it is conditioned on the short distance properties of the interaction, requiring the presence of a sufficiently large soft core in the interaction potential.