Physical extraction of antigen and information.

To respond and adapt, cells use surface receptors to sense environmental cues. While biochemical signal processing inside the cell is studied in depth, less is known about how physical processes during cell-cell contact impact signal acquisition. New experiments found that fast-evolving immune B cells in germinal centers (GCs) apply force to acquire antigen clusters prior to internalization, suggesting adaptive benefits of physical information extraction. We present a theory of stochastic antigen transfer and show that maximizing information gain via physical extraction can explain the dramatic phenotypic transition from naive to GC B cells-attenuated receptor signaling, enhanced force usage, and decentralized contact architecture. Our model suggests that binding-lifetime measurement and physical extraction serve as complementary modes of antigen recognition, greatly extending the dynamic range of affinity discrimination when combined. This physical-information framework further predicts that the optimal size of receptor clusters decreases as affinity improves, rationalizing the use of a multifocal synaptic pattern seen in GC B cells. By linking extraction dynamics to selection fidelity via discriminatory performance, we propose that cells may physically enhance information acquisition to sustain adaptive evolution.

Biodegradable nanoplatforms for antigen delivery: part I - state of the art review of polymeric nanoparticles for cancer immunotherapy.

INTRODUCTION: Polymeric nanoparticles used for antigen delivery against infections and for cancer immunotherapy are an emerging therapeutic strategy in promoting the development of innovative vaccines. Beyond their capability to create targeted delivery systems with controlled release of payloads, biodegradable polymers are utilized for their ability to enhance the immunogenicity and stability of antigens. AREAS COVERED: This review extensively discusses the physicochemical parameters that affect the behavior of nanoparticles as antigen-delivery systems. Additionally, various types of natural and synthetic polymers and recent advancements in nanoparticle-based targeted vaccine production are reviewed. EXPERT OPINION: Biodegradable polymeric nanoparticles have gained major interest in the vaccination filed and have been extensively used to encapsulate antigens against a wide variety of tumors. Moreover, their versatility in terms of tunning their physicochemical characteristics, and their surface, facilitates the targeting to antigen presenting cells and enhances immune response.

Development of an antigen-based approach to noninvasively image CAR T cells in real time and as a predictive tool.

CAR T cell therapy has revolutionized the treatment of a spectrum of blood-related malignancies. However, treatment responses vary among cancer types and patients. Accurate monitoring of CAR T cell dynamics is crucial for understanding and evaluating treatment efficacy. Positron emission tomography (PET) offers a comprehensive view of CAR T cell homing, especially in critical organs such as lymphoid structures and bone marrow. This information will help assess treatment response and predict relapse risk. Current PET imaging methods for CAR T require genetic modifications, limiting clinical use. To overcome this, we developed an antigen-based imaging approach enabling whole-body CAR T cell imaging. The probe detects CAR T cells in vivo without affecting their function. In an immunocompetent B cell leukemia model, CAR-PET signal in the spleen predicted early mortality risk. The antigen-based CAR-PET approach allows assessment of CAR T therapy responses without altering established clinical protocols. It seamlessly integrates with FDA-approved and future CAR T cell generations, facilitating broader clinical application.

Self-Assembled Ferritin Nanoparticles for Delivery of Antigens and Development of Vaccines: From Structure and Property to Applications.

Ferritin, an iron storage protein, is ubiquitously distributed across diverse life forms, fulfilling crucial roles encompassing iron retention, conversion, orchestration of cellular iron metabolism, and safeguarding cells against oxidative harm. Noteworthy attributes of ferritin include its innate amenability to facile modification, scalable mass production, as well as exceptional stability and safety. In addition, ferritin boasts unique physicochemical properties, including pH responsiveness, resilience to elevated temperatures, and resistance to a myriad of denaturing agents. Therefore, ferritin serves as the substrate for creating nanomaterials typified by uniform particle dimensions and exceptional biocompatibility. Comprising 24 subunits, each ferritin nanocage demonstrates self-assembly capabilities, culminating in the formation of nanostructures akin to intricate cages. Recent years have witnessed the ascendance of ferritin-based self-assembled nanoparticles, owing to their distinctive physicochemical traits, which confer substantial advantages and wide-ranging applications within the biomedical domain. Ferritin is highly appealing as a carrier for delivering drug molecules and antigen proteins due to its distinctive structural and biochemical properties. This review aims to highlight recent advances in the use of self-assembled ferritin as a novel carrier for antigen delivery and vaccine development, discussing the molecular mechanisms underlying its action, and presenting it as a promising and effective strategy for the future of vaccine development.

[Analysis of the effectiveness of cross-reactive carbohydrate antigen determinant antibody adsorbents in identifying allergen-specific IgE antibodies].

This study aimed to investigate the influence of anti-cross-reactive carbohydrate determinant IgE antibodies (anti-CCD IgE) on the detection of allergen-specific IgE (sIgE) antibodies, as well as the application value of anti-CCD IgE adsorbents in detecting allergen sIgE. In this cross-sectional study, a total of 2 636 test samples from patients who received treatment in West China Hospital of Sichuan University and tested allergen sIgE using the western blot method from October 2020 to May 2021 were analyzed. In these samples, 709 samples tested postive of allergen sIgE. 46 stochastic venous serum samples that tested positive in both sIgE and anti-CCD IgE and 1 serum sample that tested positive in sIgE but negative in anti-CCD IgE were collected. These samples were processed by anti-CCD IgE adsorbents, followed by allergen sIgE detection. The difference between the two detection results before and after adsorption was analyzed. The allergen test results showed that the positive rate of anti-CCD IgE in samples was 2.6% (69/2 636) during the period of sample collection. After treatment with anti-CCD IgE adsorbents, the top three allergen-sIgE of the positive rate changed from tree combination 2 (willow/poplar/elm), common ragweed and peanut to dust mite combination, cockroach and crab. The positive anti-CCD IgE results of 46 samples all turned negative and the total positive sIgE antibody dropped by 62.8%; the positive rate of sIgE antibodies with the class result ≥2 significantly decreased after treatment with anti-CCD IgE adsorbents, especially the positive rate of common ragweed dropped by 96.2%. The results of positive samples showed that multiple sIgE antibodies declined by different ranges, involving up to 11 antibodies with a maximum decline of 4 classes. Strongly positive sIgE antibodies (the class result ≥4) also had a high conversion rate of negative (25.0%-100%). The positive sIgE antibodies in about 60% of the samples decreased by more than 2, and the sIgE antibodies in 17.4% of the samples turned completely negative. There was no change in the allergen sIgE detection results of the sample with negative anti-CCD IgE after treatment. In conclusion, sIgE antibodies including targeting common ragweed, humulus, tree combination 2 (willow/poplar/elm), etc. are susceptible to false positives caused by anti-CCD IgE. Treatment of samples with anti-CCD IgE adsorbents can significantly reduce the risk of false positives caused by anti-CCD IgE. It is necessary to pretreat samples that were anti-CCD IgE positive with anti-CCD IgE adsorbents, which can make laboratory results more accurate and provide a reference for diagnosis and prevention of allergic diseases.

Pretrainable geometric graph neural network for antibody affinity maturation.

Increasing the binding affinity of an antibody to its target antigen is a crucial task in antibody therapeutics development. This paper presents a pretrainable geometric graph neural network, GearBind, and explores its potential in in silico affinity maturation. Leveraging multi-relational graph construction, multi-level geometric message passing and contrastive pretraining on mass-scale, unlabeled protein structural data, GearBind outperforms previous state-of-the-art approaches on SKEMPI and an independent test set. A powerful ensemble model based on GearBind is then derived and used to successfully enhance the binding of two antibodies with distinct formats and target antigens. ELISA EC50 values of the designed antibody mutants are decreased by up to 17 fold, and KD values by up to 6.1 fold. These promising results underscore the utility of geometric deep learning and effective pretraining in macromolecule interaction modeling tasks.

Global awareness of antigenic peptides - Unraveling the impact on sickle cell anemia patients in the presence of pathogens: A narrative review.

Sickle cell anemia (SCA) is a genetic blood disorder characterized by the production of abnormal hemoglobin S (HbS), leading to sickle-shaped red blood cells and various complications, including increased susceptibility to infections. The presence of antigenic peptides, short amino acid sequences derived from pathogens or altered self-proteins, plays a crucial role in immune responses. This review explores the global awareness of antigenic peptides, their role in immune responses in SCA patients, and the challenges and opportunities in managing infections within this vulnerable population. Antigenic peptides are central to the adaptive immune response, facilitating the recognition and elimination of pathogens by T-cells. In SCA, altered antigen presentation and impaired T-cell responses due to chronic inflammation, functional asplenia, and ongoing hemolysis contribute to increased susceptibility to infections. Pathogens such as Streptococcus pneumoniae and Haemophilus influenzae pose significant risks to SCA patients, highlighting the importance of robust immune responses mediated by antigenic peptides. Strategies such as vaccination and immunotherapy aim to enhance immune function by targeting specific antigenic peptides, thereby reducing infection rates and improving patient outcomes. Advances in genomics and proteomics offer insights into individual variations in antigen presentation and immune responses, guiding the development of tailored therapeutic interventions. Global collaborations are essential to address disparities in healthcare access and implement effective preventive measures, ensuring equitable outcomes for SCA patients worldwide.

Advancements in the preparation technology of small molecule artificial antigens and their specific antibodies: a comprehensive review.

Small molecules find extensive application in medicine, food safety, and environmental studies, particularly in biomedicine. Immunoassay technology, leveraging the specific recognition between antigens and antibodies, offers a superior alternative to traditional physical and chemical analysis methods. This approach allows for the rapid and accurate detection of small molecular compounds, owing to its high sensitivity, specificity, and swift analytical capabilities. However, small molecular compounds often struggle to effectively stimulate an immune response due to their low molecular weight, weak antigenicity, and limited antigenic epitopes. To overcome this, coupling small molecule compounds with macromolecular carriers to form complete antigens is typically required to induce specific antibodies in animals. Consequently, the preparation of small-molecule artificial antigens and the production of efficient specific antibodies are crucial for achieving precise immunoassays. This paper reviews recent advancements in small molecule antibody preparation technology, emphasizing the design and synthesis of haptens, the coupling of haptens with carriers, the purification and identification of artificial antigens, and the preparation of specific antibodies. Additionally, it evaluates the current technological shortcomings and limitations while projecting future trends in artificial antigen synthesis and antibody preparation technology.

Novel insights into the application of recombinant mutated phospholipases D as antigens for developing new strategies against Loxoscelism.

Loxoscelism is the pathological condition triggered by a brown spider bite. The venom of these spiders is rich in phospholipases D (PLDs), which can induce virtually all local and systemic manifestations. Recombinant mutated PLDs from clinically relevant Loxosceles species in South America have been investigated as potential antigens to develop novel therapeutic strategies for loxoscelism. However, certain gaps need to be addressed before a clinical approach can be implemented. In this study, we examined the potential of these recombinant mutated PLDs as antigens by testing some variations in the immunization scheme. Furthermore, we evaluated the efficacy of the produced antibodies in neutralizing the nephrotoxicity and sphingomyelinase activity of brown spider venoms. Our findings indicate that the number of immunizations has a greater impact on the effectiveness of neutralization compared to the amount of antigen. Specifically, two or three doses were equally effective in reducing dermonecrosis and edema. Additionally, three immunizations proved to be more effective in neutralizing mice lethality than one or two. Moreover, immunizations mitigated the signs of kidney injury, a crucial aspect given that acute renal failure is a serious systemic complication. In vitro inhibition of the sphingomyelinase activity of Loxosceles venoms, a key factor in vivo toxicity, was nearly complete after incubation with antibodies raised against these antigens. These findings underscore the importance of implementing an effective immunization scheme with multiple immunizations, without the need for high antigen doses, and enhances the spectrum of neutralization exhibited by antibodies generated with these antigens. In summary, these results highlight the strong potential of these antigens for the development of new therapeutic strategies against cutaneous and systemic manifestations of loxoscelism.

Nerve-Glial antigen 2: unmasking the enigmatic cellular identity in the central nervous system.

Chondroitin sulfate proteoglycans (CSPGs) are fundamental components of the extracellular matrix in the central nervous system (CNS). Among these, the Nerve-Glial antigen 2 (NG2) stands out as a transmembrane CSPG exclusively expressed in a different population of cells collectively termed NG2-expressing cells. These enigmatic cells, found throughout the developing and adult CNS, have been indicated with various names, including NG2 progenitor cells, polydendrocytes, synantocytes, NG2 cells, and NG2-Glia, but are more commonly referred to as oligodendrocyte progenitor cells. Characterized by high proliferation rates and unique morphology, NG2-expressing cells stand apart from neurons, astrocytes, and oligodendrocytes. Intriguingly, some NG2-expressing cells form functional glutamatergic synapses with neurons, challenging the long-held belief that only neurons possess the intricate machinery required for neurotransmission. In the CNS, the complexity surrounding NG2-expressing cells extends to their classification. Additionally, NG2 expression has been documented in pericytes and immune cells, suggesting a role in regulating brain innate immunity and neuro-immune crosstalk in homeostasis. Ongoing debates revolve around their heterogeneity, potential as progenitors for various cell types, responses to neuroinflammation, and the role of NG2. Therefore, this review aims to shed light on the enigma of NG2-expressing cells by delving into their structure, functions, and signaling pathways. We will critically evaluate the literature on NG2 expression across the CNS, and address the contentious issues surrounding their classification and roles in neuroinflammation and neurodegeneration. By unraveling the intricacies of NG2-expressing cells, we hope to pave the way for a more comprehensive understanding of their contributions to CNS health and during neurological disorders.

Integrating molecular dynamics simulation with small- and wide-angle X-ray scattering to unravel the flexibility, antigen-blocking, and protease-restoring functions in a hindrance-based pro-antibody.

Spatial hindrance-based pro-antibodies (pro-Abs) are engineered antibodies to reduce monoclonal antibodies' (mAbs) on-target toxicity using universal designed blocking segments that mask mAb antigen-binding sites through spatial hindrance. By linking through protease substrates and linkers, these blocking segments can be removed site-specifically. Although many types of blocking segments have been developed, such as coiled-coil and hinge-based Ab locks, the molecular structure of the pro-Ab, particularly the region showing how the blocking fragment blocks the mAb, has not been elucidated by X-ray crystallography or cryo-EM. To achieve maximal effect, a pro-Ab must have high antigen-blocking and protease-restoring efficiencies, but the unclear structure limits its further optimization. Here, we utilized molecular dynamics (MD) simulations to study the dynamic structures of a hinge-based Ab lock pro-Ab, pro-Nivolumab, and validated the simulated structures with small- and wide-angle X-ray scattering (SWAXS). The MD results were closely consistent with SWAXS data (χ2 best-fit = 1.845, χ2 allMD = 3.080). The further analysis shows a pronounced flexibility of the Ab lock (root-mean-square deviation = 10.90 Å), yet it still masks the important antigen-binding residues by 57.3%-88.4%, explaining its 250-folded antigen-blocking efficiency. The introduced protease accessible surface area method affirmed better protease efficiency for light chain (33.03 Å2) over heavy chain (5.06 Å2), which aligns with the experiments. Overall, we developed MD-SWAXS validation method to study the dynamics of flexible blocking segments and introduced methodologies to estimate their antigen-blocking and protease-restoring efficiencies, which would potentially be advancing the clinical applications of any spatial hindrance-based pro-Ab.

Effect of antigen removal in hypersensitivity pneumonitis.

BACKGROUND: Antigen removal is a cornerstone of treatment of hypersensitivity pneumonitis (HP), but its association with transplant-free survival remains unclear. Further, HP guidelines conflict as to whether antigen removal is a recommended diagnostic test in patients with suspected HP. OBJECTIVE: The purpose of this study is to (1) evaluate the impact of antigen removal on transplant-free survival and (2) to describe the impact of antigen removal on pulmonary function testing and imaging in a retrospective cohort of patients with HP. METHODS: We retrospectively identified HP patients evaluated between 2011 and 2020. Demographic, physiologic, radiographic, and pathologic data were recorded. RESULTS: 212 patients were included in the cohort. Patients who identified and removed antigen had a better transplant-free survival than patients who did not identify antigen and patients who identified but did not remove antigen. Antigen removal was associated with improvement in FVC by 10% predicted in 16.9% of patients with fibrotic HP and 56.7% of patients with nonfibrotic HP. DISCUSSION: Our results suggest that over 50% of nonfibrotic HP patients and 16.9% of fibrotic HP patients improve with exposure removal. In addition, antigen removal, rather than antigen identification, is associated with transplant-free survival in HP.

Antigen specificity affects analysis of natural antibodies.

Natural antibodies are used to compare immune systems across taxa, to study wildlife disease ecology, and as selection markers in livestock breeding. These immunoglobulins are present prior to immune stimulation. They are described as having low antigen specificity or polyreactive binding and are measured by binding to self-antigens or novel exogenous proteins. Most studies use only one or two antigens to measure natural antibodies and ignore potential effects of antigen specificity in analyses. It remains unclear how different antigen-specific natural antibodies are related or how diversity among natural antibodies may affect analyses of these immunoglobulins. Using genetically distinct lines of chickens as a model system, we tested the hypotheses that (1) antigen-specific natural antibodies are independent of each other and (2) antigen specificity affects the comparison of natural antibodies among animals. We used blood cell agglutination and enzyme-linked immunosorbent assays to measure levels of natural antibodies binding to four antigens: (i) rabbit erythrocytes, (ii) keyhole limpet hemocyanin, (iii) phytohemagglutinin, or (iv) ovalbumin. We observed that levels of antigen specific natural antibodies were not correlated. There were significant differences in levels of natural antibodies among lines of chickens, indicating genetic variation for natural antibody production. However, line distinctions were not consistent among antigen specific natural antibodies. These data show that natural antibodies are a pool of relatively distinct immunoglobulins, and that antigen specificity may affect interpretation of natural antibody function and comparative immunology.

Both sides now: evolutionary traits of antigens and B cells in tolerance and activation.

B cells are the cornerstone of our body's defense system, producing precise antibodies and safeguarding immunological memory for future protection against pathogens. While we have a thorough understanding of how naïve B cells differentiate into plasma or memory B cells, the early B cell response to various antigens-whether self or foreign-remains a thrilling and evolving area of study. Advances in imaging have illuminated the molecular intricacies of B cell receptor (BCR) signaling, yet the dynamic nature of B cell activation continues to reveal new insights based on the nature of antigen exposure. This review explores the evolutionary journey of B cells as they adapt to the unique challenges presented by pathogens. We begin by examining the specific traits of antigens that influence their pathogenic potential, then shift our focus to the distinct characteristics of B cells that counteract these threats. From foundational discoveries to the latest cutting-edge research, we investigate how B cells are effectively activated and distinguish between self and non-self antigens, ensuring a balanced immune response that defends against pathogenic diseases but not self-antigens.

B cells require DOCK8 to elicit and integrate T cell help when antigen is limiting.

Dedicator of cytokinesis 8 (DOCK8) immunodeficiency syndrome is characterized by a failure of the germinal center response, a process involving the proliferation and positive selection of antigen-specific B cells. Here, we describe how DOCK8-deficient B cells are blocked at a light-zone checkpoint in the germinal centers of immunized mice, where they are unable to respond to T cell-dependent survival and selection signals and consequently differentiate into plasma cells or memory B cells. Although DOCK8-deficient B cells can acquire and present antigen to initiate activation of cognate T cells, integrin up-regulation, B cell-T cell conjugate formation, and costimulation are insufficient for sustained B cell and T cell activation when antigen availability is limited. Our findings provide an explanation for the failure of the humoral response in DOCK8 immunodeficiency syndrome and insight into how the level of available antigen modulates B cell-T cell cross-talk to fine-tune humoral immune responses and immunological memory.

Development of novel humanized VHH synthetic libraries based on physicochemical analyses.

Due to the high affinity and specificity of antibodies toward antigens, various antibody-based applications have been developed. Recently, variable antigen-binding domains of heavy-chain antibodies (VHH) have become an attractive alternative to conventional fragment antibodies due to their unique molecular characteristics. As an antibody-generating strategy, synthetic VHH libraries (including humanized VHH libraries) have been developed using distinct strategies to constrain the diversity of amino acid sequences. In this study, we designed and constructed several novel synthetic humanized VHH libraries based on biophysical analyses conducted using the complementarity determining region-grafting method and comprehensive sequence analyses of VHHs deposited in the protein data bank. We obtained VHHs from the libraries, and hit clones exhibited considerable thermal stability. We also found that VHHs from distinct libraries tended to have different epitopes. Based on our results, we propose a strategy for generating humanized VHHs with distinct epitopes toward various antigens by utilizing our library combinations.

TCR clustering by contrastive learning on antigen specificity.

Effective clustering of T-cell receptor (TCR) sequences could be used to predict their antigen-specificities. TCRs with highly dissimilar sequences can bind to the same antigen, thus making their clustering into a common antigen group a central challenge. Here, we develop TouCAN, a method that relies on contrastive learning and pretrained protein language models to perform TCR sequence clustering and antigen-specificity predictions. Following training, TouCAN demonstrates the ability to cluster highly dissimilar TCRs into common antigen groups. Additionally, TouCAN demonstrates TCR clustering performance and antigen-specificity predictions comparable to other leading methods in the field.

Engineering of pH-dependent antigen binding properties for toxin-targeting IgG1 antibodies using light-chain shuffling.

Immunoglobulin G (IgG) antibodies that bind their cognate antigen in a pH-dependent manner (acid-switched antibodies) can release their bound antigen for degradation in the acidic environment of endosomes, while the IgGs are rescued by the neonatal Fc receptor (FcRn). Thus, such IgGs can neutralize multiple antigens over time and therefore be used at lower doses than their non-pH-responsive counterparts. Here, we show that light-chain shuffling combined with phage display technology can be used to discover IgG1 antibodies with increased pH-dependent antigen binding properties, using the snake venom toxins, myotoxin II and α-cobratoxin, as examples. We reveal differences in how the selected IgG1s engage their antigens and human FcRn and show how these differences translate into distinct cellular handling properties related to their pH-dependent antigen binding phenotypes and Fc-engineering for improved FcRn binding. Our study showcases the complexity of engineering pH-dependent antigen binding IgG1s and demonstrates the effects on cellular antibody-antigen recycling.

Size matters: Altering antigen specific immune tolerance by tuning size of particles.

Precisely co-delivering antigens and immunosuppressants via nano/microcarriers to antigen-presenting cells (APCs) to induce antigen-specific immune tolerance represents a highly promising strategy for treating or preventing autoimmune diseases. The physicochemical properties of nano/microcarriers play a pivotal role in regulating immune function, with particle size and surface charge emerging as crucial parameters. In particular, very few studies have investigated micron-scale carriers of antigens. Herein, various nanoparticles and microparticles (NPs/MPs) with diverse particle sizes (ranging from 200 nm to 5 µm) and surface charges were prepared. Antigen peptides (MOG35-55) and immunosuppressants were encapsulated in these particles to induce antigen-specific immune tolerance. Two emulsifiers, PVA and PEMA, were employed to confer different surface charges to the NPs/MPs. The in vitro and in vivo studies demonstrated that NP/MP-PEMA could induce immune tolerance earlier than NP/MP-PVA and that NP/MP-PVA could induce immune tolerance more slowly and sustainably, indicating that highly negatively charged particles can induce immune tolerance more rapidly. Among the different sizes and charged particles tested, 200-nm-NP-PVA and 3-µm-MP-PEMA induced the greatest immune tolerance. In addition, the combination of NPs with MPs can further improve the induction of immune tolerance. In particular, combining 200 nm-NP-PVA with 3 µm-MP-PEMA or combining 500 nm-NP-PEMA with 3 µm-MP-PVA had optimal therapeutic efficacy. This study offers a new perspective for treating diseases by combining NPs with MPs and applying different emulsifiers to prepare NPs and MPs.

Rentabilidad de la ratio angiogénica en el seguimiento de gestantes de alto riesgo de preeclampsia precoz tratadas con ácido acetilsalicílico / Profitability of the angiogenic ratio in the follow-up of pregnant women at high risk of early preeclampsia treated with acetylsalicylic acid

Objetivo: Evaluar el valor predictivo negativo de la ratio antigénica y conocer su rentabilidad para descartar preeclampsia precoz en pacientes de alto riesgo de desarrollarla, con profilaxis de ácido acetilsalicílico. Métodos: Se realizó un estudio descriptivo transversal que recogió a las gestantes con cribado de preeclampsia precoz de alto riesgo (384 gestantes) en el Hospital Santa Lucía durante el año 2021, para lo que se usó test Elecsys® tabulado a un riesgo mayor a 1/150 en primer trimestre, y que tomaran ácido acetilsalicílico antes de la semana 16, quedando en 368 gestantes vistas en las semanas 20, 26, 31 y 36. Se realizó biometría, ratio angiogénica y doppler. Resultados: La incidencia de preeclampsia precoz en la población fue 4 casos (incidencia 1,08 %). Son significativos por su alto valor predictivo negativo del 100 % de preeclampsia precoz: la ratio angiogénica mayor a 38 en la semana 26 y el doppler de las uterinas en semana 20 y 26. Conclusión: En gestaciones con cribado de alto riesgo de preeclampsia que tomen ácido acetilsalicílico, una ratio angiogénica menor a 38 en la semana 26, además de un doppler uterino normal en semana 20 y 26 permite reducir el seguimiento gestacional(AU)

Objective: Our main objective was to evaluate the negative predictive value of the angiogenic ratio and to know its profitability to rule out early preeclampsia in patients at high risk of early preeclampsia with acetylsalicylic acid prophylaxis. Methods: A cross-sectional descriptive study was carried out that included pregnant women with high-risk early preeclampsia screening (384 pregnant women) at the Santa Lucía Hospital during the year 2021, for which the Elecsys® test tabulated at a risk >1/ was used. 150 in the first trimester, and who take acetylsalicylic acid before week 16, leaving 368 pregnant women seen in weeks 20, 26, 31 and 36, with biometry, angiogenic ratio and Doppler performed. Results: The incidence of early preeclampsia in the population was 4 cases (incidence 1.08%). They are significant due to their high negative predictive value of 100% of early preeclampsia: Angiogenic ratio > 38 in week 26, uterine Doppler in weeks 20 and 26. Conclusion: Pregnancies with high risk screening for preeclampsia who take acid acetylsalicylic acid, an angiogenic ratio < 38 at week 26 in addition to a normal uterine Doppler at weeks 20 and 26 allows for reduced gestational follow-up(AU)