Adult Peripheral Blood Research Articles

Abstract 2905: SENTI-301A, an off-the-shelf multi-armed preclinical CAR-NK cell therapy, for the treatment of GPC3 expressing tumors

Abstract Purpose: SENTI-301A is a novel off-the-shelf CAR-NK product candidate that uses gene circuits to enhance NK cell persistence and targeted cytotoxicity to address unmet needs in GPC3 expressing solid tumors such as hepatocellular carcinomas (HCC). Experimental procedures: SENTI-301A is a Multi-Armed, targeted chimeric antigen receptor (CAR) NK cell preclinical product candidate with a GPC3 CAR and calibrated-release interleukin-15 (crIL-15) engineered onto allogeneic healthy adult peripheral blood NK cells. The activating CAR is designed to target GPC3, an antigen overexpressed in several cancers, such as HCC. crIL-15 is a unique technology attaching wild type IL-15 to the membrane via a linker that can be cleaved by a ubiquitous protease. This results in membrane-bound and secreted IL-15 to provide both autocrine support to the CAR NK cells, and paracrine stimulation to other surrounding immune cells in the tumor microenvironment for enhanced antitumor response. Results: SENTI-301A exhibited increased crIL-15-driven survival and expansion (>30 days) without exogenous cytokine support compared to unengineered NK cells (~6 days). SENTI-301A also showed significantly higher in vitro cytotoxic activity (~20%) against GPC3 expressing cell lines compared to isogenic cells lacking the antigen, indicating CAR-mediated activation and antigen specificity. SENTI-301A also showed significant tumor killing function, IFNg, and Granzyme-B production, when co-cultured with HCC and other GPC3 expressing tumor cell lines at different effector:target ratios. SENTI-301A maintained the antitumor function in the presence of full-length soluble GPC3, reducing the risk of competition from shedding GPC3 with surface GPC3 for CAR-NK cell binding. In HCC mouse xenograft models, SENTI-301A showed NK cells tumor infiltration, and displayed enhanced persistence, antitumor function and increased median survival (p< 0.01), in comparison to unengineered NK cells. As next steps, the potential positive impact of immune checkpoint inhibitors (CPIs) in combination with SENTI-301A to enhance anticancer function is being assessed. Conclusions: SENTI-301A is a novel off-the-shelf preclinical CAR-NK cell therapy candidate that targets GPC3-expressing tumors in an antigen-specific manner and exhibits increased persistence via crIL-15. We are exploring the potential synergy between SENTI-301A and CPIs to enhance the existing antitumor functions of SENTI-301A. SENTI-301A is planned for clinical development with an investigational new drug application (IND) expected in 2023. Citation Format: Marcela Guzman Ayala, Deepika Kaveri, Enping Hong, Elizabeth Leitner, Priscilla Wong, Ronni Ponek, Lawrence Naitmazi, Pearley Chinta, Wesley Gorman, Mengxi Tian, Niran Almudhfar, Kelly Lee, Nicholas Frankel, Alba Gonzalez Junca, Russell Gordley, Philip Lee, Timothy Lu, Kanya Rajangam. SENTI-301A, an off-the-shelf multi-armed preclinical CAR-NK cell therapy, for the treatment of GPC3 expressing tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2905.

CLL stereotyped B-cell receptor immunoglobulin sequences are recurrent in the B-cell repertoire of healthy individuals: Apparent lack of central and early peripheral tolerance censoring.

The leukemic cells of patients with chronic lymphocytic leukemia (CLL) are often unique, expressing remarkably similar IGHV-IGHD-IGHJ gene rearrangements, "stereotyped BCRs". The B-cell receptors (BCRs) on CLL cells are also distinctive in often deriving from autoreactive B lymphocytes, leading to the assumption of a defect in immune tolerance. Using bulk and single-cell immunoglobulin heavy and light chain variable domain sequencing, we enumerated CLL stereotype-like IGHV-IGHD-IGHJ sequences (CLL-SLS) in B cells from cord blood (CB) and adult peripheral blood (PBMC) and bone marrow (BM of healthy donors. CLL-SLS were found at similar frequencies among CB, BM, and PBMC, suggesting that age does not influence CLL-SLS levels. Moreover, the frequencies of CLL-SLS did not differ among B lymphocytes in the BM at early stages of development, and only re-circulating marginal zone B cells contained significantly higher CLL-SLS frequencies than other mature B-cell subpopulations. Although we identified CLL-SLS corresponding to most of the CLL major stereotyped subsets, CLL-SLS frequencies did not correlate with those found in patients. Interestingly, in CB samples, half of the CLL-SLS identified were attributed to two IGHV-mutated subsets. We also found satellite CLL-SLS among the same normal samples, and they were also enriched in naïve B cells but unexpectedly, these were ~10-fold higher than standard CLL-SLS. In general, IGHV-mutated CLL-SLS subsets were enriched among antigen-experienced B-cell subpopulations, and IGHV-unmutated CLL-SLS were found mostly in antigen-inexperienced B cells. Nevertheless, CLL-SLS with an IGHV-mutation status matching that of CLL clones varied among the normal B-cell subpopulations, suggesting that specific CLL-SLS could originate from distinct subpopulations of normal B cells. Lastly, using single-cell DNA sequencing, we identified paired IGH and IGL rearrangements in normal B lymphocytes resembling those of stereotyped BCRs in CLL, although some differed from those in patients based on IG isotype or somatic mutation. CLL-SLS are present in normal B-lymphocyte populations at all stages of development. Thus, despite their autoreactive profile they are not deleted by central tolerance mechanisms, possibly because the level of autoreactivity is not registered as dangerous by deletion mechanisms or because editing of L-chain variable genes occurred which our experimental approach could not identify.

Investigating anti-inflammatory and immunomodulatory properties of brivaracetam and lacosamide in experimental autoimmune encephalomyelitis (EAE)

PurposeInflammation plays a role in drug-resistant epilepsy (DRE). We have previously reported an increased proportion of CD4 T cells displaying a pro-inflammatory profile in the peripheral blood of adults with DRE. Specific anti-epileptic drugs (AEDs) exhibit immunomodulatory properties that could increase the risk of infections but also contribute to their beneficial impact on DRE and other neurological diseases. The impact of novel generation AEDs on the profile of immune cells and on neuroinflammatory processes remains unclear. MethodsWe compared the influence of brivaracetam and lacosamide on the activation of human and murine peripheral immune cells in vitro and in vivo in active experimental autoimmune encephalomyelitis (EAE), a common mouse model of central nervous system inflammation. ResultsWe found that brivaracetam and lacosamide at 2.5 μg/ml did not impair the survival and activation of human immune cells, but a higher dose of 25 μg/ml decreased mitogen-induced proliferation of CD8 T cells in vitro. Exposure to high doses of brivaracetam, and to a lesser extent lacosamide, reduced the proportion of CD25+ and CD107a+ CD8+ human T cells in vitro, and the frequency of CNS-infiltrating CD8+ T cells at EAE onset and CD11b+ myeloid cells at peak in vivo. Prophylactic administration of brivaracetam or lacosamide did not delay EAE onset but significantly improved the clinical course in the chronic phase of EAE compared to control. ConclusionNovel generation AEDs do not impair the response to immunization with MOG peptide but improve the course of EAE, possibly through a reduction of neuroaxonal damage.

Frequency of Nucleated Red Blood Cells in the Peripheral Blood of ICU-Admitted Patients.

To evaluate the clinical significance of NRBCs in the peripheral blood of critically ill patients admitted to the ICU to find a cut-off to predict mortality. A cross-sectional study was carried out over a period of six months September 1, 2020, to March 31, 2021, in Lahore, Pakistan. A totalof 800 critically ill patients of both sexes in the age group of 18-70 years were included. Patients younger than 18 years and patients who underwentsurgery were excluded. A quantity of 3 ml of whole blood sample in an ethylenediamine tetraacetic acid (EDTA) vial from each patient was run on SYSMEX XN-9000 (Sysmex Corporation, Kobe, Hyogo, Japan) and the results were reviewed on peripheral smears. The incidence of NRBCs in ICU-admitted patients was 62.5% (500/800). The total number of NRBC-positive patients recovering after the treatment was 364 (72.8%). The overall mortality of NRBC-positive patients was 30% (150/500). It was significantly higher (p<0.001) than that of NRBC-negative patients (14%; 44/300).During treatment, the highest mortality rate was seen in patients due to malignancy (100%), followed by sepsis (58.8%). It was observed that the disease pattern and number of NRBCs were significantly different (p<0.001) among all disease groups. However, there was no statistically significant difference in NRBCs on the basis of gender (p >0.05). In our study, a cutoff of NRBCs of 2.50 showed a high risk of mortality with a sensitivity of 91%. The presence of NRBCs may predict mortality in critically ill ICU-admitted patients. Their presence in the blood may be regarded as a marker of severity suggesting a high risk of ICU death.

Skewed fate and hematopoiesis of CD34+ HSPCs in umbilical cord blood amid the COVID-19 pandemic.

Umbilical cord blood (UCB) is an irreplaceable source for hematopoietic stem progenitor cells (HSPCs). However, the effects of SARS-CoV-2 infection and COVID-19 vaccination on UCB phenotype, specifically the HSPCs therein, are currently unknown. We thus evaluated any effects of SARS-CoV-2 infection and/or COVID-19 vaccination from the mother on the fate and functionalities of HSPCs in the UCB. The numbers and frequencies of HSPCs in the UCB decreased significantly in donors with previous SARS-CoV-2 infection and more so with COVID-19 vaccination via the induction of apoptosis, likely mediated by IFN-γ-dependent pathways. Two independent hematopoiesis assays, a colony forming unit assay and a mouse humanization assay, revealed skewed hematopoiesis of HSPCs obtained from donors delivered from mothers with SARS-CoV-2 infection history. These results indicate that SARS-CoV-2 infection and COVID-19 vaccination impair the functionalities and survivability of HSPCs in the UCB, which would make unprecedented concerns on the future of HSPC-based therapies.

Alterations in the Humoral Immunophenotype of Children with Sickle Cell Disease on Hydroxyurea

Background: Sickle Cell Disease (SCD) is a red blood cell disorder associated with hemolysis and inflammation affecting homeostasis of the blood system. Both innate and T-cell driven adaptive immune systems are involved in SCD-linked inflammation. The involvement of B-cell compartment in etiology of SCD is much less studied. While complex interactions of ischemia-reperfusion, inflammation, and hemolysis affecting the bone marrow and immune system have been studied in adults with SCD, much less is known how their interplay affects SCD etiology in children. Objective: To determine the range of immune changes we assessed the frequency of 12 immune populations via flow cytometry, evaluated B cell related cytokines, and performed bulk RNA sequencing of the peripheral blood (PB) of pediatric patients with SCD as compared to pediatric race-matched controls as well adult patients with SCD as compared to adult race-matched controls. Method: Adult control PB was obtained from Rhode Island Blood Center. Pediatric control and pediatric and adult SCD PB were obtained from Rhode Island Hospital Hematology and Primary Care clinics. All informed consents/assents were obtained. PB samples were stained using markers identifying 12 immune populations including CD8, CD4, T Regulatory, B cells, Plasmablasts, Monocytes, Dendritic, Granulocytes, Neutrophils, Basophils, Eosinophils, and Stem Cells. Flow cytometry was performed on BDTM LSRII and analyzed using FlowJo. RNA was isolated from pediatric SCD or control PB and RNA-seq was performed by Novogene. Plasma from all patients (SCD and controls) was processed for cytokine analysis using Biolegend's LEGENDplex Human B Cell Panel. Demographics, clinical, and laboratory data were obtained from chart review. Results: Thirteen pediatric patients (ages 1-16, mean 8.7 years) and 12 adult patients (ages 8-15, mean 32.2 years) with SCD on Hydroxyurea were enrolled. HbSS genotype was found in 92.3% pediatrics and 66.7% adults. Mean Hydroxyurea dose was 23.4 mg/kg or 20.0 mg/kg for pediatric or adult SCD, respectively. Five pediatric controls (ages 9-14, mean 11.4 years) and 10 adult controls (ages 18-53, mean 31.0 years) were enrolled. Laboratory data indicated elevated hemolysis in pediatric and adult SCD with mean Absolute Reticulocyte Count (ARC) 203 ± 94.2 for pediatric SCD and 214 ± 169 for adult SCD. Flow cytometry data revealed 1.9-fold increase (p= 0.012) of CD3+CD4+ cells in Pediatric SCD versus pediatric controls, this change was not seen in adult SCD versus adult controls (Table 1). Pediatric SCD patients had 3.5-fold increase (p=0.005) in CD19+ B cells without further increase in differentiated B cells, this change was not seen in adult SCD versus adult controls (Table 1). Subsequent analysis of B cell related cytokines revealed significant increase in IL2 (p =0.013), IL4 (p=0.026), TNFβ (p= 0.039), and IL13 (p=0.034) in pediatric SCD versus pediatric controls; there was no significance for these cytokines in adult SCD versus adult controls. BAFF was elevated in both pediatric and adult SCD versus age-matched controls (p=0.041 and p=0.005, respectively). Finally, bulk RNA sequencing of pediatric SCD or control PB indicated significant changes in transcripts linked to humoral immunity. Over Representation Analysis (ORA) of cell type revealed upregulation of transcripts linked to pro-B cells (29 genes), plasma cells (37 genes) and CD34 Positive Pre-B cells (10 genes), (Figure 1). These results suggested significant alteration of the B cell maturation in pediatric SCD samples. Conclusions: Our data indicate significant changes in CD4+ and CD19+ cells in pediatric SCD patients versus controls. Increased CD4+ cell frequencies in children with SCD were previously reported (PMID 29926339). Our new finding of altered humoral immunity and differentiation of B cells noted by flow cytometry were consistent with elevated B-cell related cytokine levels in pediatric SCD versus pediatric controls. Elevated levels of pro-B cells, plasma cells, and CD34+ pre-B cell transcripts detected by RNA-seq in pediatric SCD patients versus controls further confirmed humoral alterations in pediatric SCD samples. Our findings point to previously unreported effect of SCD on the humoral immune system in children with SCD treated with Hydroxyurea, warranting further investigation. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Investigation of Genotoxic Damage in Overweight Individuals Using the Comet Assay

AbstractObjective: Research has revealed that obesity changed the repair mechanism of DNA chain breaks. Also, the increase in body mass index is found out to be associated with genomic instability. In this study, it was aimed to investigate the possible genotoxic damage of overweight individuals.Material and Methods: In the present study the level of genotoxic damage was calculated in Turkish adult peripheral blood samples using Single Cell Gel Electrophoresis assay. The results of possible DNA damage levels belonging to overweight people were compared statistically by SPSS analysis program with the results of normal-weight people.Results: Fifty five volunteers (21 normal weight and 34 overweight); 23 women, mean age=30.13±7.97 and 32 men, mean age=38.13±10.63 participated in the study. Tail moment is an average of 1.21±0.45 in all individuals. Tail moment value was found of overweight people as 1.29±0.46. When this value was compared with the results of individuals with normal weight (1.09±0.40), statistically no significant difference was determined (p&amp;gt;0.05). According to results, no significant difference was found between the increase in body mass index and DNA damage (p&amp;gt;0.05).Conclusion: The present study is the first study which gives information about the level of DNA damage relation with being overweight in adults of Turkey. In the presented study, it was determined that there was no relationship between body mass index and genotoxic damage according to the findings of the comet assay, and we recommended that new studies should be conducted in the future to investigate the level of DNA damage with different genotoxicity tests.

EFFECT OF HUMAN UMBILICAL CORD BLOOD PLATELET-RICH PLASMA COMBINED WITH EXTRACELLULAR MATRIX HYDROGELS ON IMMUNOCOMPETENT ENDOMETRIAL DAMAGE MURINE MODELS

Asherman syndrome or endometrial atrophy (AS/EA) are endometrial pathologies causing infertility. Human platelet-rich plasma (hPRP) contains growth factors (GF) and cytokines well-described in tissue regeneration. Adult peripheral blood hPRP has been used as therapy in different tissues, as well as for AS/EA women. Human umbilical cord blood PRP (hUC-PRP) showed greater regenerative potential than other hPRP due to its younger source. Recently, we confirmed the use of endometrial extracellular matrix hydrogels (HG) as delivery system of GF in mice.

OVA-PEG-R848 nanocapsules stimulate neonatal conventional and plasmacytoid dendritic cells.

Childhood mortality represents a major issue with 5. 3 million worldwide deaths of children under 5 years of age in 2019. Approximately half of those deaths can be attributed to easily preventable, infectious diseases. Currently approved neonatal vaccines are typically effective only after multiple doses leaving infants especially vulnerable during the first 6 months of life. Survival rates could be improved significantly by developing new and more potent vaccines that are capable of overcoming inherently tolerogenic neonatal immune systems. TLR agonists have garnered a great deal of attention in recent years due to their extensive capacities to activate innate immunity. Herein, the superior capacity of the TLR7/8 agonist, resiquimod (R848), to activate adult and neonatal primary peripheral blood dendritic cells is demonstrated. Moreover, R848 can be conjugated to polyethylene glycol and encapsulated in ovalbumin nanocapsules to efficiently co-deliver antigen and adjuvant in vitro. This study is among the first to demonstrate the capacity of encapsulated R848 to activate neonatal dendritic cells. These findings support the potential incorporation of R848 as adjuvant in neonatal vaccines, making them more effective in eliciting a robust immune response.

Abstract 11 Outcome of Patients Treated with Umbilical Cord Blood and Homologous Serum Eye Drops

IntroductionSeveral authors have demonstrated the safety and efficacy of CBS eye drops in the treatment of severe DE with or without Sjogren’s syndrome (SS-I), ocular graft versus host disease (GVHD), persistent corneal epithelial defects, recurrent corneal erosions, chemical burns, and neurotrophic keratitis.ObjectiveTo compare the efficacy of cord blood serum (CBS) and adult donor peripheral blood serum (PBS) eye drops (prepared, standardized, and controlled in the Emilia Romagna Cord Blood Bank) in the treatment of severe dry eye disease (DED), a multicenter randomized, double masked, crossover clinical trial was designed.MethodsSixty patients diagnosed with severe DED associated with persistent corneal epithelial defects were randomized and equally assigned to group A (treated with CBS) or group B (treated with PBS) , eye drops administered 8 times/day for 1 month. Primary outcome was the pre-treatment and post-treatment change in corneal fluorescein staining. Secondary outcomes included the pretreatment and post-treatment change in ocular surface disease index (OSDI), questionnaire and Visual Analogue Score (VAS) of subjective symptoms, Schirmer I test, tear break-up time, and conjunctival staining. Patients with relapse in signs or symptoms after further 2 months switched to the remaining group for one additional month.ResultsCorneal staining was more significantly reduced after CBS treatment; both VAS and OSDI score reduction was observed in both groups, but group A reported significantly less grittiness and pain. Nineteen patients shifted in the crossover period. The within individual comparison confirmed a better recovery in the CBS treatment period. Epidermal growth factor, transforming growth factor, and platelet-derived growth factor content was associated with reduction of epithelial damage. Levels of interleukins were positively associated with symptoms decrease.DiscussionDED signs improved after both CBS and PBS treatments with potential advantages of CBS for subjective symptoms and corneal damage reduction. In addition to the very important therapeutic value of EDHO products, considering the CB units not suitable for transplantation, we have identified novel non-wasteful clinical applications of those allogeneic biological products, resulting in an increase of ethical motivation of families generously donating CB for public benefit.Figure 1.Slit-lamp photographs with fluorescein staining in patient running both period 1 and period 2 of the study. Before PBS treatment, the corneal epithelium was stained diffusely (top left). One month after treatment, the severity of the damage decreased, especially in the central area (top right). Two months after the end of the treatment, the level of epithelial damage worsened and patient entered period 2 (bottom left). After 1 month of CBS treatment, a diffuse decrease in staining was observed in all areas. In this patient, a better improvement was observed after the CBS treatment compared with the PBS treatment.

Abstract 3 Generation of Myeloid Cells from Cord Blood-Derived CD34+ Cells for Therapeutic Intent

IntroductionMacrophages and monocytes traffic to and infiltrate complex solid tumor microenvironments where conditions can promote an immunosuppressive phenotype in resident tumor-associated macrophages that hinder effective anti-tumor immune responses. Ongoing advances in cell engineering are being adapted to modify monocytes and macrophages into efficacious anti-tumor cell therapies. However, a limiting factor to this promising therapy has been cell numbers, since monocytes obtained from adult peripheral blood mononuclear cells do not expand ex vivo.ObjectiveWe are developing an expanded allogeneic, cryopreserved, off-the-shelf myeloid cell product for the treatment of solid tumors.MethodsCD34+ cells isolated from pooled donor cord blood are the starting material for generation of myeloid cells. The process has three phases: (1) expansion of hematopoietic stem and progenitor cells, (2) continued expansion and differentiation into monocytes, and (3) differentiation of monocytes into mature macrophages. Cells are characterized before and after cryopreservation by immune phenotyping, morphology, and phagocytic capacity.ResultsThe current culture method produces several thousand HLA-DR+ CD11b+ myeloid cells at both the monocyte and macrophage stage per starting CD34+ cell. These cells make up ~70% of the final cell product along with a potentially beneficial heterogeneous mix of additional myeloid-derived cells. Immunophenotyping demonstrates expression of canonical monocyte/macrophage markers, including CD14, CD86, and CD163. Cell morphology after macrophage differentiation is similar to that of peripheral blood-derived mature adult macrophages. Importantly, the final cell product can be cryopreserved with excellent recovery of viable cells post-thaw that are functional, as demonstrated by maintenance of phagocytic potential when compared with pre-cryopreservation function.DiscussionThis proprietary CD34+ cell expansion and directed differentiation platform results in the generation of therapeutically relevant numbers of functional myeloid cells. Furthermore, the ability to cryopreserve these cells, with demonstrated viability and function upon thaw, facilitates their use as an off-the-shelf cell therapy, with potential for faster and less expensive routes to treatments for solid tumors that have proven resistant to other cell therapies. Additional work is being done toward engineering these myeloid cells to express proteins to enhance a patient’s anti-tumor immune responses, whether these cells are used alone or in combination with other therapeutics.

Natural killer cells 56bright16− have higher counts in the umbilical cord blood than in the adult peripheral blood

Introduction and hypothesisUmbilical cord blood (UCB) is an alternative source of hematopoietic stem cells for allogeneic hematopoietic stem cell transplantation in the absence of a compatible donor. The UCB transplantation has a lower incidence of chronic graft versus host disease (GvHD), but is associated with slower engraftment and slower immune reconstitution, compared to other sources. Dendritic cells (DCs) and Natural Killer cells (NKs) play a central role in the development of GvHD and the graft versus leukemia (GvL) effect, as well as in the control of infectious complications. MethodWe quantified by multiparametric flow cytometry monocytes, lymphocytes, NK cells, and DCs, including their subsets, in UCB samples from 54 healthy newborns and peripheral blood (PB) from 25 healthy adult volunteers. ResultsIn the UCB samples, there were higher counts of NK cells 56bright16− (median 0.024 × 109/L), compared to the PB samples (0.012 × 109/L, p < 0.0001), NK 56dim16bright (median 0.446 × 109/L vs. 0.259 × 109/L for PB samples, p = 0.001) and plasmacytoid dendritic cells (pDCs, median 0.008 × 109/L for UCB samples vs. 0.006 × 109/L for PB samples, p = 0.03). Moreover, non-classic monocyte counts were lower in UCB than in PB (median 0.024 × 109/L vs. 0.051 × 109/L, respectively, p < 0.0001). ConclusionIn conclusion, there were higher counts of NK cells and pDCs and lower counts of non-classic monocytes in UCB than in PB from healthy individuals. These findings might explain the lower incidence and severity of chronic GvHD, although maintaining the GvL effect, in UCB transplant recipients, compared to other stem cell sources.

Impact of Epstein-Barr virus co-infection on natural acquired Plasmodium vivax antibody response.

BackgroundThe simultaneous infection of Plasmodium falciparum and Epstein-Barr virus (EBV) could promote the development of the aggressive endemic Burkitt’s Lymphoma (eBL) in children living in P. falciparum holoendemic areas. While it is well-established that eBL is not related to other human malaria parasites, the impact of EBV infection on the generation of human malaria immunity remains largely unexplored. Considering that this highly prevalent herpesvirus establishes a lifelong persistent infection on B-cells with possible influence on malaria immunity, we hypothesized that EBV co-infection could have impact on the naturally acquired antibody responses to P. vivax, the most widespread human malaria parasite.Methodology/Principal findingsThe study design involved three cross-sectional surveys at six-month intervals (baseline, 6 and 12 months) among long-term P. vivax exposed individuals living in the Amazon rainforest. The approach focused on a group of malaria-exposed individuals whose EBV-DNA (amplification of balf-5 gene) was persistently detected in the peripheral blood (PersVDNA, n = 27), and an age-matched malaria-exposed group whose EBV-DNA could never be detected during the follow-up (NegVDNA, n = 29). During the follow-up period, the serological detection of EBV antibodies to lytic/ latent viral antigens showed that IgG antibodies to viral capsid antigen (VCA-p18) were significantly different between groups (PersVDNA > NegVDNA). A panel of blood-stage P. vivax antigens covering a wide range of immunogenicity confirmed that in general PersVDNA group showed low levels of antibodies as compared with NegVDNA. Interestingly, more significant differences were observed to a novel DBPII immunogen, named DEKnull-2, which has been associated with long-term neutralizing antibody response. Differences between groups were less pronounced with blood-stage antigens (such as MSP1-19) whose levels can fluctuate according to malaria transmission.Conclusions/SignificanceIn a proof-of-concept study we provide evidence that a persistent detection of EBV-DNA in peripheral blood of adults in a P. vivax semi-immune population may impact the long-term immune response to major malaria vaccine candidates.

Transmembrane Protein ANTXR1 Regulates γ-Globin Expression by Targeting the Wnt/β-Catenin Signaling Pathway.

Reactivation of fetal hemoglobin (HbF, α2γ2) alleviates clinical symptoms in patients with β-thalassemia and sickle cell disease, although the regulatory mechanisms of γ-globin expression have not yet been fully elucidated. Recent studies found that interfering with the expression of the membrane protein ANTXR1 gene upregulated γ-globin levels. However, the exact mechanism by which ANTXR1 regulates γ-globin levels remains unclear. Our study showed that overexpression and knockdown of ANTXR1 in K562, cord blood CD34+, and HUDEP-2 cells decreased and increased γ-globin expression, respectively. ANTXR1 regulates the reactivation of fetal hemoglobin (HbF, α2γ2) in K562, cord blood CD34+, and adult peripheral blood CD34+ cells through interaction with LRP6 to promote the nuclear entry of β-catenin and activate the Wnt/β-catenin signaling pathway. The overexpression or knockdown of ANTXR1 on γ-globin and Wnt/β-catenin signaling in K562 cells was reversed by the inhibitor XAV939 and the activator LiCl, respectively, where XAV939 inhibits the transcription of β-catenin in the Wnt pathway, but LiCl inhibits GSK3-β. We also showed that the binding ability of the rank4 site in the transcriptional regulatory region of the SOX6 gene to c-Jun was significantly increased after overexpression of ANTXR1 in K562 cells. SOX6 protein expression was increased significantly after overexpression of the c-Jun gene, indicating that the transcription factor c-Jun initiated the transcription of SOX6, thereby silencing γ-globin. Our findings may provide a new intervention target for the treatment of β-hemoglobinopathies.

Decreased expression of hypoxia-inducible factor 1α (HIF-1α) in cord blood monocytes under anoxia

BackgroundInfections are a major cause for morbidity and mortality in neonates; however, the underling mechanisms for increased infection susceptibility are incompletely understood. Hypoxia, which is present in inflamed tissues, has been identified as an important activation signal for innate immune cells in adults and is mainly mediated by hypoxia-inducible factor 1α (HIF-1α). Fetal tissue pO2 physiologically is low but rises immediately after birth.MethodsIn this study, the effect of low oxygen partial pressure (pO2) on HIF-1α expression and its targets phagocytosis, reactive oxygen species (ROS) production and vascular endothelial growth factor (VEGF) secretion was compared in vitro between immune cells from adult peripheral blood and cord blood using anoxia, HIF-1α stabilizer desferroxamin (DFO) and E. coli as stimuli.ResultsWe show that anoxia-induced HIF-1α protein accumulation, phagocytosis, ROS-production and VEGF-expression were greatly diminished in cord blood compared to adult cells. E. coli led to HIF-1α gene expression in adult and cord blood immune cells; however, cord blood cells failed to accumulate HIF-1α protein and VEGF upon E. coli stimulation.ConclusionsTaken together, our results show a diminished activation of cord blood immune cells by low pO2, which might contribute to impaired reactivity in the context of infection.ImpactNeonatal immune cells do not accumulate HIF-1α under low oxygen partial pressure leading to decreased phagocytosis and decreased ROS production.We demonstrate a previously unknown mechanism of reduced activation of neonatal immune cells in the context of an inflammatory response.This could contribute to the increased susceptibility of newborns and preterm infants to infection.

A Novel GMP Protocol to Produce High-Quality Treg Cells From the Pediatric Thymic Tissue to Be Employed as Cellular Therapy.

Due to their suppressive capacity, the adoptive transfer of regulatory T cells (Treg) has acquired a growing interest in controlling exacerbated inflammatory responses. Limited Treg recovery and reduced quality remain the main obstacles in most current protocols where differentiated Treg are obtained from adult peripheral blood. An alternate Treg source is umbilical cord blood, a promising source of Treg cells due to the higher frequency of naïve Treg and lower frequency of memory T cells present in the fetus’ blood. However, the Treg number isolated from cord blood remains limiting. Human thymuses routinely discarded during pediatric cardiac surgeries to access the retrosternal operative field has been recently proposed as a novel source of Treg for cellular therapy. This strategy overcomes the main limitations of current Treg sources, allowing the obtention of very high numbers of undifferentiated Treg. We have developed a novel good manufacturing practice (GMP) protocol to obtain large Treg amounts, with very high purity and suppressive capacity, from the pediatric thymus (named hereafter thyTreg). The total amount of thyTreg obtained at the end of the procedure, after a short-term culture of 7 days, reach an average of 1,757 x106 (range 50 x 106 – 13,649 x 106) cells from a single thymus. The thyTreg product obtained with our protocol shows very high viability (mean 93.25%; range 83.35% – 97.97%), very high purity (mean 92.89%; range 70.10% – 98.41% of CD25+FOXP3+ cells), stability under proinflammatory conditions and a very high suppressive capacity (inhibiting in more than 75% the proliferation of activated CD4+ and CD8+ T cells in vitro at a thyTreg:responder cells ratio of 1:1). Our thyTreg product has been approved by the Spanish Drug Agency (AEMPS) to be administered as cell therapy. We are recruiting patients in the first-in-human phase I/II clinical trial worldwide that evaluates the safety, feasibility, and efficacy of autologous thyTreg administration in children undergoing heart transplantation (NCT04924491). The high quality and amount of thyTreg and the differential features of the final product obtained with our protocol allow preparing hundreds of doses from a single thymus with improved therapeutic properties, which can be cryopreserved and could open the possibility of an “off-the-shelf” allogeneic use in another individual.

Single-cell transcriptomics reveals the identity and regulators of human mast cell progenitors

AbstractMast cell accumulation is a hallmark of a number of diseases, including allergic asthma and systemic mastocytosis. Immunoglobulin E–mediated crosslinking of the FcεRI receptors causes mast cell activation and contributes to disease pathogenesis. The mast cell lineage is one of the least studied among the hematopoietic cell lineages, and controversies remain about whether FcεRI expression appears during the mast cell progenitor stage or during terminal mast cell maturation. Here, we used single-cell transcriptomics analysis to reveal a temporal association between the appearance of FcεRI and the mast cell gene signature in CD34+ hematopoietic progenitors in adult peripheral blood. In agreement with these data, the FcεRI+ hematopoietic progenitors formed morphologically, phenotypically, and functionally mature mast cells in long-term culture assays. Single-cell transcriptomics analysis further revealed the expression patterns of prospective cytokine receptors regulating development of mast cell progenitors. Culture assays showed that interleukin-3 (IL-3) and IL-5 promoted disparate effects on progenitor cell proliferation and survival, respectively, whereas IL-33 caused robust FcεRI downregulation. Taken together, we showed that FcεRI expression appears at the progenitor stage of mast cell differentiation in peripheral blood. We also showed that external stimuli regulate FcεRI expression of mast cell progenitors, providing a possible explanation for the variable FcεRI expression levels during mast cell development.

Serum autoantibodyome reveals that healthy individuals share common autoantibodies

SUMMARYAutoantibodies are a hallmark of both autoimmune disease and cancer, but they also occur in healthy individuals. Here, we perform a meta-analysis of nine datasets and focus on the common autoantibodies shared by healthy individuals. We report 77 common autoantibodies based on the protein microarray data obtained from probing 182 healthy individual sera on 7,653 human proteins and an additional 90 healthy individual sera on 1,666 human proteins. There is no gender bias; however, the number of autoantibodies increase with age, plateauing around adolescence. We use a bioinformatics pipeline to determine possible molecular-mimicry peptides that can contribute to the elicitation of these common autoantibodies. There is enrichment of intrinsic properties of proteins like hydrophilicity, basicity, aromaticity, and flexibility for common autoantigens. Subcellular localization and tissue-expression analysis reveal that several common autoantigens are sequestered from the circulating autoantibodies.

Down-regulation of the transcriptional repressor ZNF802 (JAZF1) reactivates fetal hemoglobin in \u03b20-thalassemia/HbE

Reactivating of fetal hemoglobin (HbF; α2γ2) can ameliorate the severity of β-thalassemia disease by compensating for adult hemoglobin deficiency in patients. Previously, microarray analysis revealed that zinc finger protein (ZNF)802 (also known as Juxta-posed with another zinc finger gene-1 (JAZF1)) was upregulated in human erythroblasts derived from adult peripheral blood compared with fetal liver-derived cells, implying a potential role as a HbF repressor. However, deficiency in ZNF802 induced by lentiviral shRNA in β0-thalassemia/hemoglobinE erythroblasts had no effect on erythroblast proliferation and differentiation. Remarkably, the induction of HBG expression was observed at the transcriptional and translational levels resulting in an increase of HbF to 35.0 ± 3.5%. Interestingly, the embryonic globin transcripts were also upregulated but the translation of embryonic globin was not detected. These results suggest ZNF802 might be a transcriptional repressor of the γ-globin gene in adult erythroid cells.

Optimal Active Anti-Thymocyte Globulin Exposure Associated with Minimum Risk of Virus Reactivation and Comparable Acute Graft-Versus-Host Disease Under Adult Myeloablative Haploidentical Peripheral Blood Stem Cell Transplantation

Anti-thymocyte globulin (ATG) is often included in the conditioning regimen to prevent graft-versus-host disease (GVHD) in allogeneic hematopoietic cell transplantation (allo-HCT). However, the risk of virus reactivation increases significantly. We conducted a single-center prospective study to identify the optimal ATG exposure that ensures engraftment, effectively prevents acute GVHD, and reduces the risk of virus reactivation without increasing relapse of malignant diseases in haploidentical peripheral blood stem cell transplantation (haplo-PBSCT). From September 2018 to June 2020, 106 patients (median age, 32 years) with malignant hematological diseases who received haplo-PBSCT for the first time were enrolled. All patients received 10 mg/kg rabbit ATG (thymoglobulin) divided for 4 days (days –5 to –2). Pre-transplant, post-transplant, and total areas under the concentration–time curve (AUCs) of active ATG were calculated. Total AUC of active ATG was shown to be the best predictor for virus reactivation and acute GVHD of grades II to IV or grades III and IV. The optimal total AUC range of active ATG was 100 to 148.5 UE/mL/day. The median time was 14 versus 13 days (P = .184) for neutrophil engraftment and 13 versus 13 days (P = .263) for platelet engraftment in the optimal and non-optimal AUC groups, respectively. The optimal AUC group showed a lower cumulative incidence of cytomegalovirus (CMV) reactivation and persistent CMV viremia than the non-optimal AUC group: 60.6% (95% confidence interval [CI], 48.3%–73.1%) versus 77.1% (95% CI, 64.5%–87.7%; P = .016) and 31.5% (95% CI, 21.2%–45.3%) versus 56.3% (95% CI, 42.9%–70.4%; P = .007), respectively. The cumulative incidence of persistent Epstein–Barr virus (EBV) viremia in the optimal AUC group was significantly lower than the non-optimal total AUC group: 33.1% (95% CI, 22.5%–46.8%) versus 52.6% (95% CI, 39.3%–67.2%; P = .048). However, there was no difference in EBV reactivation (P = .752). Similar outcomes were observed for grade II to IV and grade III and IV acute GVHD between the two groups: 48.6% (95% CI, 36.8%–62.0%) versus 37.0% (95% CI, 24.8%–52.5%; P = .113) and 10.4% (95% CI, 4.8%–21.7%) versus 4.2% (95% CI, 1.0%–15.6%; P = .234, respectively. Relapse, non-relapse mortality, and disease-free survival demonstrated no significant differences between the two groups. But, overall survival at 2 years tended to increase in the optimal AUC group: 75.7% (95% CI, 62.4%–84.8%) versus 57.8% (95% CI, 42.4%–70.4%; P = .061). These data support an optimal active ATG exposure of 110 to 148.5 UE/mL/day in haplo-PBSCT. Individualized dosing of ATG in allo-HCT might reduce the risk of virus reactivation and effectively prevent acute GVHD simultaneously.