Ribosome-Targeting Antibiotics Impair T Cell Effector Function and Ameliorate Autoimmunity by Blocking Mitochondrial Protein Synthesis.

While antibiotics are intended to specifically target bacteria, most are known to affect host cell physiology. In addition, some antibiotic classes are reported as immunosuppressive for reasons that remain unclear. Here, we show that Linezolid, a ribosomal-targeting antibiotic (RAbo), effectively blocked the course of a T cell-mediated autoimmune disease. Linezolid and other RAbos were strong inhibitors of T helper-17 cell effector function in vitro, showing that this effect was independent of their antibiotic activity. Perturbing mitochondrial translation in differentiating T cells, either with RAbos or through the inhibition of mitochondrial elongation factor G1 (mEF-G1) progressively compromised the integrity of the electron transport chain. Ultimately, this led to deficient oxidative phosphorylation, diminishing nicotinamide adenine dinucleotide concentrations and impairing cytokine production in differentiating T cells. In accordance, mice lacking mEF-G1 in T cells were protected from experimental autoimmune encephalomyelitis, demonstrating that this pathway is crucial in maintaining T cell function and pathogenicity.

Abnormal biomarkers predict complex FAS or FADD defects missed by exome sequencing.

BACKGROUND: Elevated TCRαß+CD4-CD8- double-negative T cells (DNT) and serum biomarkers help identify FAS mutant patients with autoimmune lymphoproliferative syndrome (ALPS). However, in some patients with clinical features and biomarkers consistent with ALPS, germline or somatic FAS mutations cannot be identified on standard exon sequencing (ALPS-undetermined: ALPS-U). OBJECTIVE: We sought to explore whether complex genetic alterations in the FAS gene escaping standard sequencing or mutations in other FAS pathway-related genes could explain these cases. METHODS: Genetic analysis included whole FAS gene sequencing, copy number variation analysis, and sequencing of FAS cDNA and other FAS pathway-related genes. It was guided by FAS expression analysis on CD57+DNT, which can predict somatic loss of heterozygosity (sLOH). RESULTS: Nine of 16 patients with ALPS-U lacked FAS expression on CD57+DNT predicting heterozygous "loss-of-expression" FAS mutations plus acquired somatic second hits in the FAS gene, enriched in DNT. Indeed, 7 of 9 analyzed patients carried deep intronic mutations or large deletions in the FAS gene combined with sLOH detectable in DNT; 1 patient showed a FAS exon duplication. Three patients had reduced FAS expression, and 2 of them harbored mutations in the FAS promoter, which reduced FAS expression in reporter assays. Three of the 4 ALPS-U patients with normal FAS expression carried heterozygous FADD mutations with sLOH. CONCLUSION: A combination of serum biomarkers and DNT phenotyping is an accurate means to identify patients with ALPS who are missed by routine exome sequencing.

Abrocitinib Provides Rapid and Sustained Improvement in Skin Pain and Is Associated with Improved Quality of Life Outcomes in Adult and Adolescent Patients with Moderate-to-Severe Atopic Dermatitis.

BACKGROUND: Skin pain in atopic dermatitis (AD) increases with disease severity and is associated with substantial quality of life (QoL) burden. OBJECTIVES: The aim of the study was to evaluate abrocitinib efficacy on skin pain and QoL in adults and adolescents with moderate-to-severe AD. METHODS: This post hoc analysis included data with abrocitinib administered as monotherapy (pooled phase 2b [NCT02780167] and phase 3 JADE MONO-1 [NCT03349060] and JADE MONO-2 [NCT03575871]) or in combination with topical therapy (phase 3 JADE COMPARE [NCT03720470] and JADE TEEN [NCT03796676]). Patients received oral, once-daily abrocitinib 200 mg, abrocitinib 100 mg, or placebo for 12 or 16 weeks (JADE COMPARE). Skin pain was rated using the Pruritus and Symptoms Assessment for Atopic Dermatitis (PSAAD) skin pain Numerical Rating Scale (NRS) item ("How painful was your skin over the past 24 h?") on a scale from 0 (not painful) to 10 (extremely painful). Itch (Peak Pruritus NRS) and QoL (Dermatology Life Quality Index or Children's Dermatology Life Quality Index) were assessed. Least squares mean (LSM) change from baseline was analyzed using mixed-effects repeated measures modeling. RESULTS: A total of 1,822 patients (monotherapy pool, n = 942; JADE COMPARE, n = 595; and JADE TEEN, n = 285) were analyzed. LSM change from baseline in PSAAD skin pain score was significantly greater with abrocitinib versus placebo from week 2 through week 12 or 16 across all 3 study populations and occurred in a dose-dependent manner. A greater proportion of patients achieved a ≥4-point improvement from baseline in PSAAD skin pain score with abrocitinib (200 mg and 100 mg) versus placebo in the monotherapy pool (56% and 38% vs. 12%; week 12), JADE COMPARE (72% and 52% vs. 26%; week 16), and JADE TEEN (51% and 60% vs. 31%; week 12). Additionally, a greater proportion of patients achieved a stringent threshold of skin pain improvement (PSAAD skin pain score <2) with abrocitinib versus placebo. Adults and adolescents who achieved a ≥4-point improvement in skin pain reported greater QoL improvement than those who did not achieve a ≥4-point improvement. A positive correlation (≥0.3) was observed between skin pain and QoL and separately between skin pain and itch across the 3 study populations. CONCLUSION: Abrocitinib as monotherapy or in combination with topical therapy improved skin pain and was associated with improved QoL in both adults and adolescents with moderate-to-severe AD across all evaluated studies.

CAD-CAM natural restorations-Reproducing nature using a digital workflow.

OBJECTIVES: Natural restorations combine digital workflow and shell technique to create CAD/CAM restorations with the form and texture of natural teeth. This case report describes an interdisciplinary digital workflow combined with CAD/CAM natural restorations to achieve the naturalness of an anterior rehabilitation. CLINICAL CONSIDERATIONS: A 38-year-old patient attended to the office with esthetic issues. An interdisciplinary treatment plan was conducted, which included periodontal surgery to recreate the gingival contour, associated with bleaching and manufacturing CAD/CAM ceramic veneers to return an optimal teeth surface texture and shape. CONCLUSIONS: The design and manufacturing of CAD/CAM natural restorations using a digital workflow allowed a predictable result and overcame the limitations of conventional shell technique. CLINICAL SIGNIFICANCE: Conventional shell technique is used to create restorations with the form and texture of natural teeth. This article presents a combination of the conventional shell technique with a digital workflow, facilitating the design and manufacturing of CAD/CAM natural restorations.

IROCA-TES: Improving Quality in Radiation Oncology through Clinical Audits - Training and Education for Standardization.

Background: Clinical audits are an important tool to objectively assess clinical protocols, procedures, and processes and to detect deviations from good clinical practice. The main aim of this project is to determine adherence to a core set of consensus- based quality indicators and then to compare the institutions in order to identify best practices. Materials and methods: We conduct a multicentre, international clinical audit of six comprehensive cancer centres in Poland, Spain, Italy, Portugal, France, and Romania as a part of the project, known as IROCATES (Improving Quality in Radiation Oncology through Clinical Audits - Training and Education for Standardization). Results: Radiotherapy practice varies from country to country, in part due to historical, economic, linguistic, and cultural differences. The institutions developed their own processes to suit their existing clinical practice. Conclusions: We believe that this study will contribute to establishing the value of routinely performing multi-institutional clinical audits and will lead to improvement of radiotherapy practice at the participating centres.

Temperature and exudativory as drivers of the marmoset (Callithrix spp.) daily activity period.

Primates are affected by fluctuations in ambient temperatures, mostly through thermoregulatory costs and changes in the availability of food. In the present study, we investigate whether the ambient temperature and proxies of food availability affect the activity period of marmosets (Callithrix spp.). We predicted that: (i) at colder sites, marmosets would spend more time at sleeping sites; (ii) midday resting bouts would be longer at hotter sites; (iii) the onset/cessation of activity and resting behavior at midday would be more closely related to temperature than food availability, and (iv) highly exudativorous groups would have higher total levels of resting. We compiled data on the onset and cessation of activity and the time spent resting at midday from seven marmoset studies from sites with a wide range of temperatures. We used generalized linear mixed models to verify the relationship between the dependent variables (lag between dawn and the onset of activities, lag between cessation of activities and dusk, and proportion of resting during midday) and the minimum and maximum temperatures at the respective study sites, together with proxies of food availability (exudativory rates, the amount of habitat available per individual, and net primary productivity) using each sample month as a sampling unit and the identity of the study as a categorical random factor. At colder sites and during colder months, the marmosets left sleeping trees later in the morning and ceased their activities earlier, while at hotter sites and during hotter months, they spent more time resting during midday. More exudativorous groups become active later in the morning, but also ceased their activities later. The abundance of food did not affect the timing of activities. We provide evidence that both low and high temperatures affect marmosets' activities, and that their activity period appears to be more influenced by the thermal environment than food availability.

Pathological stage, surgical margin and lymphovascular invasion as prognostic factors after salvage radiotherapy for post-prostatectomy relapsed prostate cancer - outcomes and optimization strategies.

BACKGROUND: Salvage radiotherapy (sRT) is the main potentially curative treatment after biochemical failure/locoregional relapse post-radical prostatectomy (RP). The aim of the study was to characterize the population who underwent sRT after RP at our Department, to understand the influence of several potential prognosis factors, and to determine possible optimization strategies. MATERIALS AND METHODS: We retrospectively analyzed patients undergoing sRT at our department between 2012 and 2017, evaluating patient, tumor and treatment characteristics, restaging procedures and clinical outcomes - namely biochemical relapse-free survival (BC-RFS), clinical relapse-free survival (C-RFS), additional hormone therapy-free survival (HT-FS) and overall survival (OS). We assessed potential prognostic factors by univariate and multivariate models (MVA). RESULTS: We included 277 patients (median age 68 years). Median pre-sRT PSA was > 0.5ng/mL in 54.9%. All underwent prostate bed irradiation. Pelvic lymph nodes were included in 9.7%. Outcome analysis was performed for 264 patients (35.6 months median follow-up). At 3 years, BC-RFS was 61.4%, C-RFS was 81.3%, HT-FS was 79.9% and OS was 96.6%. Most relapses occurred in regional lymph nodes only (47.9% patients who relapsed). On MVA, lymphovascular invasion, advanced pT-stages and negative margins negatively influenced BC-RFS (p = 0.029, p = 0.002 and p < 0.001) and HT-FS (p = 0.001, p = 0.029 and p = 0.002). C-RFS was worsened by lymphovascular invasion (p = 0.009) and negative margins (p = 0.015). These had no effect on OS. BC-RFS and HT-FS were improved when sRT started while PSA ≤ 0.5 ng/mL (p < 0.05). CONCLUSION: Lymphovascular invasion, higher pT-stages and negative margins negatively affected prognosis. An early start of sRT (PSA ≤ 0.5 ng/mL) predicted better BC-RFS and HT-FS.

Metallopeptidase Stp1 activates the transcription factor Sre1 in the carotenogenic yeast Xanthophyllomyces dendrorhous.

Xanthophyllomyces dendrorhous is a basidiomycete yeast known as a natural producer of astaxanthin, a carotenoid of commercial interest because of its antioxidant properties. Recent studies indicated that X. dendrorhous has a functional SREBP pathway involved in the regulation of isoprenoid compound biosynthesis, which includes ergosterol and carotenoids. SREBP is a major regulator of sterol metabolism and homeostasis in mammals; characterization in fungi also provides information about its role in the hypoxia adaptation response and virulence. SREBP protease processing is required to activate SREBP pathway functions in fungi. Here, we identified and described the STP1 gene, which encodes a metallopeptidase of the M50 family involved in the proteolytic activation of the transcription factor Sre1 of the SREBP pathway, in X. dendrorhous We assessed STP1 function in Δstp1 strains derived from the wild-type and a mutant of ergosterol biosynthesis that overproduces carotenoids and sterols. Bioinformatic analysis of the deduced protein predicted the presence of characteristic features identified in homologs from mammals and fungi. The Δstp1 mutation decreased yeast growth in the presence of azole drugs and reduced transcript levels of Sre1-dependent genes. This mutation also negatively affected the carotenoid- and sterol-overproducing phenotype. Western blot analysis demonstrated that Sre1 was activated in the yeast ergosterol biosynthesis mutant and that the Δstp1 mutation introduced in this strain prevented Sre1 proteolytic activation. Overall, our results demonstrate that STP1 encodes a metallopeptidase involved in proteolytic activation of Sre1 in X. dendrorhous, contributing to our understanding of fungal SREBP pathways.

Profound immunodeficiency with severe skin disease explained by concomitant novel CARMIL2 and PLEC1 loss-of-function mutations.

This study reports a patient with severe skin disease in the context of profound immunodeficiency explained by two concomitant genetic diseases caused by two novel homozygous loss-of-function mutations in PLEC1 and CARMIL2. The work provides additional information on the clinical and immunological manifestations of CARMIL2 deficiency and highlights the particular diagnostic and therapeutic challenge represented by the concomitant presence of two rare monogenic disorders.

A new RelB-dependent CD117+ CD172a+ murine DC subset preferentially induces Th2 differentiation and supports airway hyperresponses in vivo.

The NF-κB transcription factor subunit RelB is important for the full activation of conventional dendritic cells (cDCs) during T-cell-dependent immune responses. Although the number of splenic DCs is greatly reduced in RelBnull mice, the cause and consequences of this deficiency are currently unknown. To circumvent the impact of the pleiotropic defects in RelBnull mice we used a reporter model for RelB expression (RelBKatushka mice) and conditionally deleted RelB in DCs (RelBCD11c-Cre mice). Thereby, we can show here that RelB is essential for the differentiation of a CD117+ CD172a+ cDC subpopulation that highly expresses RelB. Surprisingly, these DCs depend on p50 for their development and are negatively regulated by a constitutive p52 activation in absence of p100. The absence of p52/p100 had no influence on the homeostasis of CD117+ CD172a+ cDCs. RelB-dependent CD117+ CD172a+ DCs strongly induce the production of the type 2 cytokines IL-4 and IL-13, as well as GM-CSF from naïve Th cells. Consequently, mice lacking RelB in cDCs show an attenuated bronchial hyperresponsiveness with reduced eosinophil infiltration. Taken together, we have identified a new splenic RelB-dependent CD117+ CD172a+ cDC population that preferentially induces Th2 responses.

Disruption of de novo fatty acid synthesis via acetyl-CoA carboxylase 1 inhibition prevents acute graft-versus-host disease.

Upon antigen-specific or allogeneic activation, T cells sharply increase their metabolic activity to cope with augmented needs for proliferation and effector functions. Therefore, enzymes involved in energy metabolism constitute attractive targets to modulate the activity of pathogenic effector T cells in the setting of graft-versus-host-disease (GVHD). Here, we show that T cells deficient for acetyl-CoA carboxylase 1 (TACC1) are dramatically less pathogenic than wild-type (WT) T cells in a lethal C57BL/6 into BALB/c model of acute GVHD and permitted sustained survival of recipient mice. In line with this clinical observation, higher frequencies of GVHD-suppressing Foxp3(+) regulatory T (Treg) cells were detected in the colon of TACC T-cell recipients. In vitro, T-cell stimulation with allogeneic DCs induced higher proportions of Treg cells but also led to diminished proliferation of TACC1 T cells compared to WT T cells. Furthermore, TACC1 T cells activated by allogeneic DCs showed impaired glycolysis and lipid synthesis. Thus, targeting de novo fatty acid synthesis via acetyl-CoA carboxylase inhibition may be a promising new strategy to prevent GVHD.

Improving radiation oncology through clinical audits: Introducing the IROCA project.

As radiotherapy practice and processes become more complex, the need to assure quality control becomes ever greater. At present, no international consensus exists with regards to the optimal quality control indicators for radiotherapy; moreover, few clinical audits have been conducted in the field of radiotherapy. The present article describes the aims and current status of the international IROCA "Improving Radiation Oncology Through Clinical Audits" project. The project has several important aims, including the selection of key quality indicators, the design and implementation of an international audit, and the harmonization of key aspects of radiotherapy processes among participating institutions. The primary aim is to improve the processes that directly impact clinical outcomes for patients. The experience gained from this initiative may serve as the basis for an internationally accepted clinical audit model for radiotherapy.

Local Ecological Knowledge about Endangered Primates in a Rural Community in Paraíba, Brazil.

The study of local ecological knowledge (LEK) fosters a better understanding of the relationship between humans and the environment. We assessed respondents' ecological knowledge of primates in a rural community located near the Atlantic Forest remnants in the state of Paraíba, Brazil. Populations of Alouatta belzebul (red-handed howler monkeys), Sapajus flavius (blonde capuchins), and Callithrix jacchus (the common marmoset) inhabit the region. We conducted 200 semi-structured interviews and applied thematic content analysis, with weighting, to the responses to quantify the LEK. Respondents showed a low LEK, despite the community's proximity to forest remnants. However, the LEK was significantly higher among men, as well as among those who had a greater degree of contact with the primates. Age did not influence LEK. The studied community apparently does not intensively exploit the forest resources nor does it economically depend on primates, which may explain these individuals' low levels of knowledge about these animals. Such data may support future studies, as well as environmental education and action plans, especially for A. belzebul and S. flavius, both of which are endangered species and targets of the National Action Plan for the Conservation of the Primates of the Northeast.

Radiotherapy for granulocytic sarcoma of the breast-Case report and review of the literature.

Granulocytic sarcomas are rare tumors that can present in innumerous locations; thus there is very little clinical experience with these cases. Therefore there is no consensus on which is the best treatment for patients with this malignancy. The authors present a case of a female with a granulocytic sarcoma of the breast and review the literature for the role of radiotherapy in the management of this clinical entity.

Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma of the Urinary Bladder: A Case Report of a Rare Presentation.

Primary lymphoma of the urinary bladder is extremely rare. We present the case of a 67-year-old woman diagnosed with primary extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT) of the urinary bladder. The patient presented with macroscopic hematuria. Renal ultrasound revealed a solid vascularized mass, in the inferior wall of the bladder. Pelvic computed tomography (CT) and magnetic resonance imaging (MRI) confirmed the presence of a polypoid lesion on the left side of the inferior bladder wall, measuring 40x45 mm, and the MRI study with gadolinium revealed that the entire bladder wall was involved. The patient underwent transurethral resection of the bladder tumor, demonstrating a histologic extensive involvement of bladder tissue by MALT lymphoma. The patient was treated with radiotherapy (24 Gy in 12 fractions) and four cycles of rituximab. She remained without evidence of disease 12 months later.

Dietary xylo-oligosaccharides and arabinoxylans improved growth efficiency by reducing gut epithelial cell turnover in broiler chickens.

BACKGROUND: One of the main roles of the intestinal mucosa is to protect against environmental hazards. Supplementation of xylo-oligosaccharides (XOS) is known to selectively stimulate the growth of beneficial intestinal bacteria and improve gut health and function in chickens. XOS may have an impact on the integrity of the intestinal epithelia where cell turnover is critical to maintain the compatibility between the digestive and barrier functions. The aim of the study was to evaluate the effect of XOS and an arabinoxylan-rich fraction (AXRF) supplementation on gut function and epithelial integrity in broiler chickens. METHODS: A total of 128 broiler chickens (Ross 308) were assigned into one of two different dietary treatments for a period of 42 d: 1) control diet consisting of a corn/soybean meal-based diet; or 2) a control diet supplemented with 0.5% XOS and 1% AXRF. Each treatment was randomly distributed across 8 pens (n = 8) with 8 chickens each. Feed intake and body weight were recorded weekly. On d 42, one male chicken per pen was selected based on average weight and euthanized, jejunum samples were collected for proteomics analysis. RESULTS: Dietary XOS/AXRF supplementation improved feed efficiency (P < 0.05) from d 1 to 42 compared to the control group. Proteomic analysis was used to understand the mechanism of improved efficiency uncovering 346 differentially abundant proteins (DAP) (Padj < 0.00001) in supplemented chickens compared to the non-supplemented group. In the jejunum, the DAP translated into decreased ATP production indicating lower energy expenditure by the tissue (e.g., inhibition of glycolysis and tricarboxylic acid cycle pathways). In addition, DAP were associated with decreased epithelial cell differentiation, and migration by reducing the actin polymerization pathway. Putting the two main pathways together, XOS/AXRF supplementation may decrease around 19% the energy required for the maintenance of the gastrointestinal tract. CONCLUSIONS: Dietary XOS/AXRF supplementation improved growth efficiency by reducing epithelial cell migration and differentiation (hence, turnover), actin polymerization, and consequently energy requirement for maintenance of the jejunum of broiler chickens.

Neuropathological and sociodemographic factors associated with the cortical amyloid load in aging and Alzheimer's disease.

Alzheimer's disease (AD) is the leading cause of dementia and is characterized by a progressive decline in cognitive abilities. A pathological hallmark of AD is a region-specific accumulation of the amyloid-beta protein (Aß). Here, we explored the association between regional Aß deposition, sociodemographic, and local biochemical factors. We quantified the Aß burden in postmortem cortical samples from parietal (PCx) and temporal (TCx) regions of 27 cognitively unimpaired (CU) and 15 AD donors, aged 78-100 + years. Histological images of Aß immunohistochemistry and local concentrations of pathological and inflammatory proteins were obtained at the "Aging, Dementia and TBI Study" open database. We used the area fraction fractionator stereological methodology to quantify the Aß burden in the gray and white matter within each cortical region. We found higher Aß burdens in the TCx of AD octogenarians compared to CU ones. We also found higher Aß loads in the PCx of AD nonagenarians than in AD octogenarians. Moreover, AD women exhibited increased Aß deposition compared to CU women. Interestingly, we observed a negative correlation between education years and Aß burden in the white matter of both cortices in CU samples. In AD brains, the Aß40, Aß42, and pTau181 isoforms of Aß and Tau proteins were positively correlated with the Aß burden. Additionally, in the TCx of AD donors, the proinflammatory cytokine TNFα showed a positive correlation with the Aß load. These novel findings contribute to understanding the interplay between sociodemographic characteristics, local inflammatory signaling, and the development of AD-related pathology in the cerebral cortex.

Hippocampal CaMKII inhibition induces reactivation-dependent amnesia for extinction memory and causes fear relapse.

Hippocampal GluN2B subunit-containing NMDAR (GluN2B-NMDAR) activation during recall destabilizes fear extinction memory, which must undergo brain-derived neurotrophic factor (BDNF)-dependent reconsolidation to persist. Ca2+/calmodulin-dependent protein kinase II (CaMKII) is a Ser/Thr protein kinase essential for hippocampus-dependent memory processing that acts downstream GluN2B-NMDAR and controls BDNF expression, but its participation in fear extinction memory reconsolidation has not yet been studied. Using a combination of pharmacological and behavioral tools, we found that in adult male Wistar rats, intra dorsal-CA1 administration of the CaMKII inhibitors autocamtide-2-related inhibitory peptide (AIP) and KN-93, but not of their inactive analogs scrambled AIP and KN-92, after fear extinction memory recall impaired extinction and caused GluN2B-NMDAR-dependent recovery of fear. Our results indicate that hippocampal CaMKII is necessary for fear extinction reconsolidation, and suggest that modulation of its activity around the time of recall controls the inhibition that extinction exerts on learned fear.

[Recommendations for psoriasis treatment in Pediatrics]. / Recomendaciones para el tratamiento de la psoriasis en Pediatría.

Introduction: in one third of patients with psoriasis, symptoms start during childhood and adolescence, with a strong emotional and psychosocial impact. Objective: to develop a guideline for the systemic treatment of psoriasis in pediatric patients by means of recommendations based on the best available evidence. Materials and methods: Sources: articles indexed in PubMed, Epistemonikos, Google Scholar, Cochrane Library and Scielo, published between January 2010 and May 2022, in English, Spanish and Portuguese. Study selection: evidence-based clinical practice guidelines, systematic reviews, meta-analyses, randomized controlled studies, observational studies (case-control, cohort studies, real-life registries) and evaluations of biosimilar drugs in patients up to and including 17 years of age were considered. The keywords "psoriasis" and "treatment" were used in all three languages. Data extraction: the literature was evaluated using Grading of Recommendations Assessment, Development and Evaluation (GRADE) recommendations. Data synthesis: evidence tables were developed and analyzed by the expert committee. The questions for the development of recommendations were based on the PICO system (population, intervention, comparison, outcome). Results: A total of 8 recommendations and 7 points of good practice were developed. The direction and strength of the recommendations were expressed according to the GRADE system. Conclusions: the final decision on a specific therapy should be based on the best opinion of the treating physician, the individual characteristics, and the values and preferences of the patients and their caregivers.

Introducción: un tercio de los pacientes con psoriasis comienzan con sus síntomas en la niñez y la adolescencia, con fuerte impacto emocional y psicosocial. Objetivo: elaborar una guía de tratamiento sistémico de la psoriasis en pacientes pediátricos mediante recomendaciones fundamentadas en la mejor evidencia disponible. Materiales y métodos: Fuentes: artículos indexados en PubMed, Epistemonikos, Google Académico, Cochrane Library y Scielo, publicados entre enero de 2010 y mayo de 2022, en inglés, castellano y portugués. Selección de estudios: se consideraron guías de práctica clínica basadas en la evidencia, revisiones sistemáticas, metanálisis, estudios controlados y aleatorizados, estudios observacionales (casos y controles, estudios de cohortes, registros de la vida real) y evaluaciones de medicamentos biosimilares en pacientes de hasta 17 años de edad inclusive. Se utilizaron las palabras clave "psoriasis" y "tratamiento" en los tres idiomas. Extracción de datos: la bibliografía fue evaluada mediante las recomendaciones del sistema Grading of Recommendations Assessment, Development and Evaluation (GRADE). Síntesis de datos: elaboración de tablas de evidencia que fueron analizadas por el comité de expertos. Las preguntas para el desarrollo de recomendaciones se fundamentaron en el sistema PICO (población, intervención, comparación, outcome [desenlace]). Resultados: se elaboraron un total de 8 recomendaciones y 7 puntos de buena práctica. La dirección y fuerza de las recomendaciones se expresaron de acuerdo con lo sugerido por el sistema GRADE. Conclusiones: la decisión final de una terapia específica se fundamentará en la mejor opinión del médico tratante, las características individuales, y los valores y preferencias de los pacientes y sus cuidadores.