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Purpose: To determine MRSA carriage rates and genetic relationships of S. aureus strains in children attending day care centres in 14 cities from three geographic regions in Mexico.Materials and Methods: Cross-Sectional Study performed in apparently healthy children aged from 6 mo to 6 yr attending day care centres (DCCs). From September 2002 To January 2003, 2345 nasopharyngeal specimens from a similar number of children were collected. Nasopharyngeal samples for bacterial isolation were obtained by standard methods. Antimicrobial susceptibility was determined and genetic relatedness of all MRSA isolates was determined by pulsed field gel electrophoresis (PFGE).Results: S. aureus was identified in 237 children (10.1%), twenty-two children had MSRA for an overall prevalence of MRSA carriage of 0.93%. Children attending DCCs from cities located in the north and south of Mexico showed higher prevalence than children from DCCs in the central region; 1.75%, and 1.71 vs. 0.08%, respectively (P < 0.05). PFGE demonstrated six different restriction profiles of MRSA with a predominant pattern.Conclusions: We documented the presence of MRSA strain colonizing children attending DCCs in Mexico, mainly in the south and north regions of the country. Clone A and B which are closely related represented 45 % of the total of MRSA isolates. We found both, SCCmec type II and type IV strains in the three regions. [ABSTRACT FROM AUTHOR]

The 2023 monkeypox (mpox) epidemic was caused by a subclade IIb descendant of a monkeypox virus (MPXV) lineage traced back to Nigeria in 1971. Person-to-person transmission appears higher than for clade I or subclade IIa MPXV, possibly caused by genomic changes in subclade IIb MPXV. Key genomic changes could occur in the genome's low-complexity regions (LCRs), which are challenging to sequence and are often dismissed as uninformative. Here, using a combination of highly sensitive techniques, we determine a high-quality MPXV genome sequence of a representative of the current epidemic with LCRs resolved at unprecedented accuracy. This reveals significant variation in short tandem repeats within LCRs. We demonstrate that LCR entropy in the MPXV genome is significantly higher than that of single-nucleotide polymorphisms (SNPs) and that LCRs are not randomly distributed. In silico analyses indicate that expression, translation, stability, or function of MPXV orthologous poxvirus genes (OPGs), including OPG153, OPG204, and OPG208, could be affected in a manner consistent with the established "genomic accordion" evolutionary strategies of orthopoxviruses. We posit that genomic studies focusing on phenotypic MPXV differences should consider LCR variability., (© 2024. The Author(s).)

Medication errors are one of the biggest problems in healthcare. The medicines' poor labelling design (i.e. look-alike labels) is a well-recognised risk for potential confusion, wrong administration, and patient damage. Human factors and ergonomics (HFE) encourages the human-centred design of system elements, which might reduce medication errors and improve people's well-being and system performance., Objective: The aim of the present study is twofold: (i) to use a human reliability analysis technique to evaluate a medication administration task within a simulated scenario of a neonatal intensive care unit (NICU) and (ii) to estimate the impact of a human-centred design (HCD) label in medication administration compared to a look-alike (LA) label., Method: This paper used a modified version of the human error assessment and reduction technique (HEART) to analyse a medication administration task in a simulated NICU scenario. The modified technique involved expert nurses quantifying the likelihood of unreliability of a task and rating the conditions, including medicine labels, which most affect the successful completion of the task., Results: Findings suggest that error producing conditions (EPCs), such as a shortage of time available for error detection and correction, no independent checking of output, and distractions, might increase human error probability (HEP) in administering medications. Results also showed that the assessed HEP and the relative percentage of contribution to unreliability reduced by more than 40% when the HCD label was evaluated compared to the LA label., Conclusion: Including labelling design based on HFE might help increase human reliability when administering medications under critical conditions., (© 2024. The Author(s).)

Viral respiratory infections are an important public health concern due to their prevalence, transmissibility, and potential to cause serious disease. Disease severity is the product of several factors beyond the presence of the infectious agent, including specific host immune responses, host genetic makeup, and bacterial coinfections. To understand these interactions within natural infections, we designed a longitudinal cohort study actively surveilling respiratory viruses over the course of 19 months (2016 to 2018) in a diverse cohort in New York City. We integrated the molecular characterization of 800+ nasopharyngeal samples with clinical data from 104 participants. Transcriptomic data enabled the identification of respiratory pathogens in nasopharyngeal samples, the characterization of markers of immune response, the identification of signatures associated with symptom severity, individual viruses, and bacterial coinfections. Specific results include a rapid restoration of baseline conditions after infection, significant transcriptomic differences between symptomatic and asymptomatic infections, and qualitatively similar responses across different viruses. We created an interactive computational resource (Virome Data Explorer) to facilitate access to the data and visualization of analytical results., Competing Interests: RR is a member of the SAB of Diatech Pharmacogenetics and Flahy and founder of Genotwin. JS and Columbia University disclose partial ownership of SK Analytics. JS discloses consulting for BNI. DSR is now employee of "Merck & Co., Inc., Kenilworth, NJ, USA" and may hold stock. IF is now employee of Abbvie and OE is currently employee of Genotwin. All other authors have no competing interests.  , (Copyright: © 2024 Galanti et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Many genes that drive normal cellular development also contribute to oncogenesis. Medulloblastoma (MB) tumors likely arise from neuronal progenitors in the cerebellum, and we hypothesized that the heterogeneity observed in MBs with sonic hedgehog (SHH) activation could be due to differences in developmental pathways. To investigate this question, here we perform single-nucleus RNA sequencing on highly differentiated SHH MBs with extensively nodular histology and observed malignant cells resembling each stage of canonical granule neuron development. Through innovative computational approaches, we connect these results to published datasets and find that some established molecular subtypes of SHH MB appear arrested at different developmental stages. Additionally, using multiplexed proteomic imaging and MALDI imaging mass spectrometry, we identify distinct histological and metabolic profiles for highly differentiated tumors. Our approaches are applicable to understanding the interplay between heterogeneity and differentiation in other cancers and can provide important insights for the design of targeted therapies., (© 2024. The Author(s).)

Public awareness about Benthic Harmful Algal Blooms (BHABs) and their negative impacts has increased substantially over the past few decades. Even so, reports of BHABs remain relatively scarce in South America (SA). This paper provides a comprehensive overview of the current state of knowledge on BHABs in the continent, by integrating data from published articles, books, and technical reports. We recorded ∼300 different occurrences of potentially toxic BHAB species over the Caribbean, Atlantic and Pacific coasts, mostly in marine (>95%) but also in estuarine areas located from 12⁰36' N to 54⁰53' S. Over 70% of the data was published/released within the past 10 years, and ∼85% were concentrated in Brazil, Venezuela, Ecuador and Colombia. Benthic species were mainly associated with macroalgae, seagrass and sediment. Incidental detection in the plankton was also relevant, mainly in places where studies targeting BHAB species are still rare, like Argentina, Uruguay, Chile and Peru. The study listed 31 infrageneric taxa of potentially toxic benthic dinoflagellates and eight of estuarine cyanobacteria occurring in SA, with the greatest species diversity recorded in the equatorial-tropical zone, mainly in northeastern Brazil (Atlantic), Venezuela and Colombia (Caribbean), and the Galapagos Islands, Ecuador (Pacific). Local strains of Amphidinium, Gambierdiscus, Coolia and Prorocentrum spp. produced toxic compounds of emerging concern. Prorocentrum lima species complex was the most common and widely distributed taxon, followed by Ostreopsis cf. ovata. In fact, these two dinoflagellates were associated with most BHAB events in SA. Whereas the former has caused the contamination of multiple marine organisms and cases of Diarrhetic Shellfish Poisoning in subtropical and temperate areas, the latter has been associated with faunal mortalities and is suspected of causing respiratory illness to beach users in tropical places. Ciguatera Poisoning has been reported in Colombia (∼240 cases; no deaths) and Venezuela (60 cases; two deaths), and may be also a risk in other places where Gambierdiscus spp. and Fukuyoa paulensis have been reported, such as the Galapagos Islands and the tropical Brazilian coast. Despite the recent advances, negative impacts from BHABs in SA are intensified by limited research/training funding, as well as the lack of official HAB monitoring and poor analytical capability for species identification and toxin detection in parts of the continent., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Peripheral T cell lymphoma not otherwise specified (PTCL-NOS) comprises heterogeneous lymphoid malignancies characterized by pleomorphic lymphocytes and variable inflammatory cell-rich tumor microenvironment. Genetic drivers in PTCL-NOS include genomic alterations affecting the VAV1 oncogene; however, their specific role and mechanisms in PTCL-NOS remain incompletely understood. Here we show that expression of Vav1-Myo1f, a recurrent PTCL-associated VAV1 fusion, induces oncogenic transformation of CD4 + T cells. Notably, mouse Vav1-Myo1f lymphomas show T helper type 2 features analogous to high-risk GATA3 + human PTCL. Single-cell transcriptome analysis reveals that Vav1-Myo1f alters T cell differentiation and leads to accumulation of tumor-associated macrophages (TAMs) in the tumor microenvironment, a feature linked with aggressiveness in human PTCL. Importantly, therapeutic targeting of TAMs induces strong anti-lymphoma effects, highlighting the lymphoma cells' dependency on the microenvironment. These results demonstrate an oncogenic role for Vav1-Myo1f in the pathogenesis of PTCL, involving deregulation in T cell polarization, and identify the lymphoma-associated macrophage-tumor microenvironment as a therapeutic target in PTCL., Competing Interests: Declaration of interests T.P. is the recipient of a research grant from Kura Oncology, Inc. R.R. is a member of the Scientific Advisory Board of AimenBio and founder of Genotwin. None of these activities are related to the work presented in this paper., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Multi-agent combination chemotherapy can be curative in acute lymphoblastic leukemia (ALL). Still, patients with primary refractory disease or with relapsed leukemia have a very poor prognosis. Here we integrate an in-depth dissection of the mutational landscape across diagnostic and relapsed pediatric and adult ALL samples with genome-wide CRISPR screen analysis of gene-drug interactions across seven ALL chemotherapy drugs. By combining these analyses, we uncover diagnostic and relapse-specific mutational mechanisms as well as genetic drivers of chemoresistance. Functionally, our data identifies common and drug-specific pathways modulating chemotherapy response and underscores the effect of drug combinations in restricting the selection of resistance-driving genetic lesions. In addition, by identifying actionable targets for the reversal of chemotherapy resistance, these analyses open novel therapeutic opportunities for the treatment of relapse and refractory disease., Competing Interests: Competing financial interests The authors declare no competing financial interests relevant for the work reported here. Financial disclosures for Adolfo Ferrando: Consulting for Ayala Pharmaceuticals and SpringWorks Therapeutics; previous research support by Pfizer, Bristol Myers Squib, Merck, Eli Lilly; patent and reagent licensing royalties from Novartis, EMD Millipore and Applied Biological Materials.

From an ergonomics perspective, the environmental characteristics should facilitate user activities. Matching user capabilities to demands of the environment is essential. However, about some users such as those with visual impairments, there is little information available for use in designing products and spaces. There is also a gap in information regarding the commutes and needs of the visually impaired, making it even more difficult to establish how environments should be designed to include this population.This study aimed to identify the information needs of people with visual impairment in terms of: 1) Daily life activities, 2) Wayfinding in the complex built environments, 3) Use of the signals provided by the environment 4) Characteristics of the environment which reduce the usability of a space and may put the user in danger, and 5) Safety perception. Data were obtained through a semi-structured interview to which eighteen adults responded. All had either complete blindness or severe visual impairment. For orientation, the most common references were texture or changes in ground level/surface, along with such ambient elements as noise or smells. Information presented in Braille was reported as little used, due to difficulty in finding such information. Regarding safety, participants reported feeling unsafe; most mentioned crossing the street as a major risk. Using auditory, tactile or even olfactory signals may provide important information while commuting: thus, designing signals which consider and highlight these senses is paramount. Assessing features and location of existing tactile signals is also required, to identify opportunities for improving the safety and independence of people with visual impairment., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Patients with the Loeys-Dietz syndrome (LDS) have mutations in the TGF- β R1, TGF- β R2, and SMAD3 genes. However, little is known about the redox homeostasis in the thoracic aortic aneurysms (TAA) they develop. Here, we evaluate the oxidant/antioxidant profile in the TAA tissue from LDS patients and compare it with that in nondamaged aortic tissue from control (C) subjects. We evaluate the enzymatic activities of glutathione peroxidase (GPx), glutathione S-transferase (GST), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) isoforms, and thioredoxin reductase (TrxR). We also analyze some antioxidants from a nonenzymatic system such as selenium (Se), glutathione (GSH), and total antioxidant capacity (TAC). Oxidative stress markers such as lipid peroxidation and carbonylation, as well as xanthine oxidase (ORX) and nuclear factor erythroid 2-related factor 2 (Nrf2) expressions, were also evaluated. TAA from LDS patients showed a decrease in GSH, Se, TAC, GPx, GST, CAT, and TrxR. The SOD activity and ORX expressions were increased, but the Nrf2 expression was decreased. The results suggest that the redox homeostasis is altered in the TAA from LDS patients, favoring ROS overproduction that contributes to the decrease in GSH and TAC and leads to LPO and carbonylation. The decrease in Se and Nrf2 alters the activity and/or expression of some antioxidant enzymes, thus favoring a positive feedback oxidative background that contributes to the TAA formation., Competing Interests: All the authors declare that there are no competing interests regarding the publication of this paper., (Copyright © 2020 Maria Elena Soto et al.)

Background: When performing, classical guitarists interact with many elements which constitute their own "workstation". One of those elements is the support for guitar positioning. Support dimensions, form and materials may determine posture and affect the musician's comfort and performance., Objective: To propose design requirements for new supports for guitar positioning, based on postural assessment, anthropometric criteria, self-efficacy and comfort perception., Methods: Nine healthy Classical Guitar students were recruited. A postural assessment was undertaken using REBA, and 3DSSPP software with three different supports for guitar positioning. After the use of each support, a questionnaire about self-efficacy and comfort perception was completed by the participants., Results: The higher scores of risk and a significant difference (ANOVA, p =≤05) regarding the left leg elevation were found with footstool usage. However, this one was identified by participants as the best support in terms of self-efficacy and comfort assessment., Conclusions: To improve performance and prevent physical injuries for guitarists, there is a need for designing guitar positionings supports based on ergonomics principles. This paper proposes eleven guidelines for designing these supports.

While knowledge of protein-protein interactions (PPIs) is critical for understanding virus-host relationships, limitations on the scalability of high-throughput methods have hampered their identification beyond a number of well-studied viruses. Here, we implement an in silico computational framework (pathogen host interactome prediction using structure similarity [P-HIPSTer]) that employs structural information to predict ∼282,000 pan viral-human PPIs with an experimental validation rate of ∼76%. In addition to rediscovering known biology, P-HIPSTer has yielded a series of new findings: the discovery of shared and unique machinery employed across human-infecting viruses, a likely role for ZIKV-ESR1 interactions in modulating viral replication, the identification of PPIs that discriminate between human papilloma viruses (HPVs) with high and low oncogenic potential, and a structure-enabled history of evolutionary selective pressure imposed on the human proteome. Further, P-HIPSTer enables discovery of previously unappreciated cellular circuits that act on human-infecting viruses and provides insight into experimentally intractable viruses., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Background: Rhabdomyosarcoma is the most common sarcoma of soft tissues in childhood and adolescence, with an annual incidence of 4-7 cases per million children aged 15. Embryonal rhabdomyosarcoma is common in adults younger than 30 years, and are usually presented as a large painless, palpable mass (> 5cm). Survival in the case of paratesticular sarcoma in men is approximately 50%., Clinical Case: Male 27 years of age with no history of importance, was seen in a clinic with an increased, painless, left testicular volume 3 years onset. Intrascrotal left testicle increased volume, with dimensions of 20×12×8cm, a stone and left inguinal node in induratum measuring 2×2cm. Microscopically, it showed a pattern of an embryonal rhabdomyosarcoma with left inguinal node metastases., Conclusion: Early diagnosis of testicular tumours, and especially of primary intratesticular rhabdomyosarcomas, and aggressive surgical treatment in combination with chemotherapy reduces the incidence of local recurrence and may improve the rate of disease-free survival and overall survival in adult patients with metastases., (Copyright © 2015 Academia Mexicana de Cirugía A.C. Publicado por Masson Doyma México S.A. All rights reserved.)

Gene expression data are accumulating exponentially in public repositories. Reanalysis and integration of themed collections from these studies may provide new insights, but requires further human curation. Here we report a crowdsourcing project to annotate and reanalyse a large number of gene expression profiles from Gene Expression Omnibus (GEO). Through a massive open online course on Coursera, over 70 participants from over 25 countries identify and annotate 2,460 single-gene perturbation signatures, 839 disease versus normal signatures, and 906 drug perturbation signatures. All these signatures are unique and are manually validated for quality. Global analysis of these signatures confirms known associations and identifies novel associations between genes, diseases and drugs. The manually curated signatures are used as a training set to develop classifiers for extracting similar signatures from the entire GEO repository. We develop a web portal to serve these signatures for query, download and visualization.

Pollution by heavy metals in marine ecosystems in the Gulf of Mexico is one of the hardest conservation issues to solve. Sharks as top predators are bioindicators of the marine ecosystem health, since they tend to bioaccumulate and biomagnify contaminants; they also represent a food source for local consumption. Thus, the objective of this study was to study the possible presence of heavy metals and a metalloid in livers of Carcharhinus limbatus. For this, a total of 19 shark livers were taken from animals captured nearby Tamihua, Veracruz, Mexico from December 2007 to April 2008. 12 out of the 19 captured sharks were males, one was an adult female, three were juvenile males, and three juvenile females. Four heavy metals (Hg, Pb, Cd, and Cr) and one metaloid (As) were analyzed in shark livers using an atomic absorption spectrophotometry with flame and hydride generator. Our results showed that the maximum concentrations found were: Hg = 0.69 mg/kg, Cd = 0.43 mg/kg, As = 27.37 mg/kg, Cr = 0.70 mg/kg. The minimum concentrations found were: As = 14.91 mg/kg, Cr = 0.35 mg/kg. The Pb could not be determined because the samples did not have the spectrophotometer minimum detectable amount (0.1 mg/kg). None of the 19 samples analyzed showed above the permissible limits established by Mexican and American laws. There was a correlation between shark size and Cr and As concentration (Pearson test). The concentration of Cr and As was observed to be higher in bigger animals. There was not a significant difference in heavy metals concentration between juveniles and adults; however, there was a difference between males and females. A higher Cr concentration was found in females when compared to males. None of the samples exceed the maximum limit established by the laws of Mexico and the United States of America. Much longer studies are needed with C. limbatus and other species caught in the region, in order to determine the degree of contaminants exposure in aquatic ecosystems and to identify potential health risks to consumers.

CD94 forms heterodimers with NKG2A, -C, or -E to constitute lectin-like natural killer cell receptors for MHC-E. Its structure differs from other C-type lectins in that the second α-helix is replaced by a loop that forms the interacting interface with the NKG2 molecules. Although CD94 has remained highly conserved mammals, several alternative splicing variants have been detected in some species. To evaluate the prevalence and significance of this phenomenon, we have cloned and sequenced CD94 cDNAs in six species of New World primates from the Cebidae and Atelidae families. Full-length sequences had a mean similarity of 96 % amongst New World primates and of 90 % to the human orthologue, with little variation in the residues interacting with NKG2 or MHC-E molecules. Despite this high conservation, a total of 14 different splice variants were identified, half of which were shared by two or more primate species. Homology-based modeling of the C-type lectin domain showed that most isoforms folded stably, although they had modifications that prevented its interaction with NKG2 and MHC-E. Two isoforms were predicted to replace the typical CD94 loop by a second α-helix, evidencing a domain fold transition from a CD94 structure to a canonical C-type lectin. These two structures were more similar to members of the CLEC lectin family than to the native CD94. Thus, CD94 has remained conserved in primates to maintain functional interactions with NKG2 and MHC-E, while at the same time has diversified by alternative splicing potentially providing additional functional scenarios.

Introduction: Plasmodium falciparum has the ability to counter the antiparasitic activity of sulphadoxine-pyrimethamine by progressively accumulating mutations in the dihydrofolate reductase (dhfr) and dihydropteroate synthase (dhps) genes. These mutations gradually increase the resistance of the parasite to these drugs and lead to therapeutic failure., Objectives: To determine the frequency of mutations associated with resistance to sulphadoxine and pyrimethamine in the dhfr and dhps genes of P. falciparum in samples from patients in three endemic zones of Colombia -La Carpa, Guaviare; Casuarito, Vichada; and Tierralta and Puerto Libertador, Córdoba., Materials and Methods: Forty samples were selected from patients with uncomplicated P. falciparum malaria. The frequency profiles of the 108, 59 and 164 alleles of dhfr were obtained by application of an allele-specific polymerase chain reaction, whereas the other alleles (alleles 51 of the dhfr gene and 436, 437 and 540 of dhps) were obtained by polymerase chain reaction and restriction fragment length polymorphism., Results: The 108N and 51I mutations in the dhfr gene were found in all of the 40 samples. No mutant alleles were found in the 59 and 164 codons of the dhfr gene, or in the 436 codon of the dhps gene. The 437G mutation was observed in 36 samples and the wild-type allele was present in 3 from Tierralta and one from La Carpa. The 540E mutation was only detected in two samples from Casuarito., Conclusions: The 108N, 51I and 437G mutations prevail in the populations of P. falciparum, indicating a cumulative effect of mutations and the need to continue surveillance for other changes which can lead to the total loss of the efficacy of sulphadoxine-pyrimethamine.

Introduction: Plasmodium falciparum is a highly polymorphic parasite, which allows it to evade the host's immune response, spread drug resistance and favours transmission., Objectives: To analyse the genetic diversity of P. falciparum populations in samples from four endemic localities in Colombia., Materials and Methods: 123 blood samples were collected on filter paper from patients with non-complicated P. falciparum malaria during 2002 to 2004. The samples were genotyped using polymerase chain reaction with specific primers for the polymorphic region of block 2 of the msp1 gene and the 108 codon of the dhfr gene., Results: In msp1 block 2, 95.9% (118/123; 95% CI: 90.8-98.7) of the samples harboured MAD20; 6.5% K1 (8/123; 95% CI: 2.8-12.4) and 2.4% RO33 (3/123; 95% CI: 0.5-6.9). For the dhfrgene the mutant allele N 108 was found in all the samples amplified, T 108 in 3.2% and the wild type S108 in 34.1%. Taking together all the results from both genes, 61.8% (76/123; 95% CI: 52.6-70.4) of the samples were simple infections and 38.2% (47/123; 95% CI: 29.6-47.4) were mixed infections. MAD20/N108-S108 (30.1%) was the most frequent combination among the latter., Conclusions: Simple infections, i.e, a single allelic type in each one of the genes studied, prevailed among the circulating parasite populations. In this study the genetic composition of P. falciparum parasite populations was very homogeneous.

Previous reports in human and mouse material demonstrated that decidual stromal cells expressed antigens associated with haematopoietic cells, exerted immune functions, and originated from bone marrow. These findings suggested that these cells belonged to the haematopoietic lineage. We purified and expanded in culture precursors of human decidual stromal cells, and found in electron microscopic images that the ultrastructure of these cells was similar to that of myofibroblasts, which are of mesenchymal origin. The relationship between these two types of cell was confirmed by the detection (by flow cytometry) in the decidual precursors of alpha-smooth muscle actin, a contractile microfilament expressed solely by smooth muscle cells, myofibroblasts and related cells. This filament was also detected in decidual stromal cells decidualized in vitro by the effect of progesterone. We also found vimentin in decidual precursors and decidualized cells. This intermediate filament has been previously reported to be expressed by all decidual stromal cells and also by myofibroblasts. Desmin, another intermediate filament expressed by myofibroblasts, was not detected in the decidual precursors; however, this filament was observed in decidualized cells. The expression of alpha-smooth muscle actin by decidual stromal cells was also found by immunostaining in cryostat sections of early decidua. Our results suggest that decidual stromal cells are related to myofibroblasts.

The origin and function of decidual stromal cells (DSC), the main cellular component of the decidua, are uncertain. Although the general consensus is that they are fibroblastic cells involved in fetal trophoblast nutrition, several authors have demonstrated that these cells can carry out immunological functions and that at least a subpopulation of them may be of hematopoietic origin. Human DSC precursors or predecidual cells (preDSC) purified by expansion in culture express a surface phenotype recalling that of dendritic cells. In the present study, we show by flow cytometry that these cells also express B7-1 (CD80) and B7-2 (CD86), two antigens involved in the costimulation of T cells by antigen-presenting cells. Cultured DSC were also able to stimulate allogenic T cells in vitro. Using an immunohistochemical technique, we found that in cryostatic sections of early human decidua, CD80 and CD86 were expressed mainly by DSC located around the decidual vessels, a location compatible with preDSC rather than fully differentiated DSC. Our results suggest that preDSC are involved in antigen presentation.