Neglected Cells: Immunomodulatory Roles of CD71+ Erythroid Cells.

The main role of red blood cells is oxygen-transportation. However, recent studies have unveiled immunomodulatory functions for their immature counterparts, CD71+ erythroid cells, under different physiological and pathological conditions. Here, I provide a perspective on the recent advances in this field to highlight their importance in health and disease.

More than just the numbers-contrasting response of snake erythrocytes to thermal acclimation.

Acclimation to lower temperatures decreases energy expenditure in ectotherms but increases oxygen consumption in most endotherms, when dropped below thermoneutrality. Such differences should be met by adjustments in oxygen transport through blood. Changes in hematological variables in correspondence to that in metabolic rates are, however, not fully understood, particularly in non-avian reptiles. We investigated the effect of thermal acclimation on a snake model, the grass snakes (Natrix natrix). After 6 months of acclimation to either 18 °C or 32 °C hematocrit, hemoglobin concentration, erythrocyte number, and size were assessed. All variables revealed significantly lower values under warm compared to cold ambient temperature. Our data suggest that non-avian reptiles, similarly as birds, reduce erythrocyte fraction under energy-demanding temperatures. Due to low deformability of nucleated erythrocytes in sauropsids, such reduced fraction may be important in decreasing blood viscosity to optimize blood flow. Novel findings on flexible erythrocyte size provide an important contribution to this optimization process.

Comparison of the Percentage of Umbilical Cord Nucleated Red Blood Cells in Preterm Neonates during Vaginal Delivery and Emergency Cesarean Section.

Background: There are insufficient and contradictory reports regarding the effect of delivery method on the rate of umbilical cord Nucleated Red Blood Cell (NRBC). Therefore, the present study aimed to compare the percentages of umbilical cord NRBC in vaginal delivery and emergency cesarean section (C-section) in preterm neonates. Materials and Methods: The present cross-sectional study was performed on mothers with vaginal delivery and C-section, from 2020 to 2021. The samples (n = 221) were preterm neonates selected using the convenience sampling method. The percentages of NRBC in neonates born by natural childbirth and by emergency C-section were measured and compared in this research. A researcher-made checklist, which included maternal and neonatal characteristics and laboratory evaluation, was used as a data collection tool. Results: The statistical population of thisresearch included 93 (42.10%) and 128 (57.90%) neonates born by vaginal delivery and by C-section, respectively.The mean (SD) score of gestational ages at birth was 30.75 (2.81) weeks. The mean (SD) score of umbilical cord NRBC level were estimated at 8.01 (5.93) and 25.64 (22.61) for the neonates born by natural childbirth and by emergency C-section, respectively (t=-8.43, df = 150, p<0.001). Statistically significant differences were observed in the gestational age (t=-3.36, df = 218, p = 0.001), fifth-minute Apgar score (t=-2.32, df = 200, p = 0.021), umbilical cord NRBC (t=-8.43, df = 160, p<0.001), and short-term prognosis (p = 0.032) between the two groups. It was also revealed that the number of NRBCs in the dead neonates was about 1.5 times higher than that in the discharged neonates. Conclusions: Based on the results of the present study, emergency C-section increased the mean of umbilical cord NRBC by three times, compared to that of normal delivery. Since an increase in the NRBC raises the risk of infant death, it is advisable to take steps to maintain the health of children by identifying high-risk neonates through umbilical cord NRBC measurement immediately after delivery and special care.

Erythroid development in the mammalian embryo.

Erythropoiesis is the process by which progenitors for red blood cells are produced and terminally differentiate. In all vertebrates, two morphologically distinct erythroid lineages (primitive, embryonic, and definitive, fetal/adult) form successively within the yolk sac, fetal liver, and marrow and are essential for normal development. Red blood cells have evolved highly specialized functions in oxygen transport, defense against oxidation, and vascular remodeling. Here we review key features of the ontogeny of red blood cell development in mammals, highlight similarities and differences revealed by genetic and gene expression profiling studies, and discuss methods for identifying erythroid cells at different stages of development and differentiation.

Impact of the seventh day nucleated red blood cell count on mortality in COVID-19 intensive care unit patients: A retrospective case-control study.

Background: COVID-19 covers a broad clinical spectrum, threatening global health. Although several studies have investigated various prognostic biochemical and hematological parameters, they generally lack specificity and are insufficient for decision-making. Beyond the neonatal period, NRBCs (nucleated red blood cells) in peripheral blood is rare and often associated with malignant neoplasms, bone marrow diseases, and other severe disorders such as sepsis and hypoxia. Therefore, we investigated if NRBCs can predict mortality in hypoxic ICU (Intensive Care Unit) patients of COVID-19. Methods: Seventy-one unvaccinated RT-PCR confirmed COVID-19 ICU patients was divided into those who survived (n=35, mean age=58) and died (n=36, mean age=75). Venous blood samples were collected in K3 EDTA tubes and analyzed on a Sysmex XN-1000 hematology analyzer with semiconductor laser flow cytometry and nucleic acid fluorescence staining method for NRBC analysis. NRBC numbers and percentages of the patients were compared on the first and seventh days of admission to the ICU. Results are reported as a proportion of NRBCs per 100 WBCs NRBCs/100 WBC (NRBC% and as absolute NRBC count (NRBC #, × 109/L). Results: NRBC 7th-day count and % values were statistically higher in non-survival ones. The sensitivity for 7th day NRBC value <0.01 (negative) was 86.11%, the specificity was 48.57%, for <0.02; 75.00%, and 77.14%, for <0.03; 61.11%, and 94.60%. Conclusions: In conclusion, our results indicate that NRBC elevation (>0.01) significantly predicts mortality in ICU hospitalized patients due to COVID-19. Worse, a high mortality rate is expected, especially with NRBC values of >0.03.

Corrigendum: High-Load Reovirus Infections Do Not Imply Physiological Impairment in Salmon.

[This corrects the article DOI: 10.3389/fphys.2019.00114.].

High-Load Reovirus Infections Do Not Imply Physiological Impairment in Salmon.

The recent ubiquitous detection of PRV among salmonids has sparked international concern about the cardiorespiratory performance of infected wild and farmed salmon. Piscine orthoreovirus (PRV) has been shown to create substantial viremia in salmon by targeting erythrocytes for principle replication. In some instances, infections develop into heart and skeletal muscle inflammation (HSMI) or other pathological conditions affecting the respiratory system. Critical to assessing the seriousness of PRV infections are controlled infection studies that measure physiological impairment to critical life support systems. Respiratory performance is such a system and here multiple indices were measured to test the hypothesis that a low-virulence strain of PRV from Pacific Canada compromises the cardiorespiratory capabilities of Atlantic salmon. Contrary to this hypothesis, the oxygen affinity and carrying capacity of erythrocytes were unaffected by PRV despite the presence of severe viremia, minor heart pathology and transient cellular activation of antiviral response pathways. Similarly, PRV-infected fish had neither sustained nor appreciable differences in respiratory capabilities compared with control fish. The lack of functional harm to salmon infected with PRV in this instance highlights that, in an era of unprecedented virus discovery, detection of viral infection does not necessarily imply bodily harm and that viral load is not always a suitable predictor of disease within a host organism.

Evaluation of Cord Blood - Haematological Scoring System as an Early Predictive Screening Method for the Detection of Early Onset Neonatal Sepsis.

BACKGROUND: Sepsis is one of the major causes of neonatal morbidity and mortality. Early recognition and diagnosis of neonatal sepsis are difficult because of the variable and non-specific clinical presentation of this condition. Hence, there is a need for early predictive screening method for neonatal sepsis. OBJECTIVES: To evaluate the role of Cord blood Haematological Scoring System as an early predictive screening method for detection of early onset neonatal sepsis and also to identify the neonates who are at risk of developing neonatal sepsis using cord blood. SETTINGS AND DESIGN: The present prospective cross-sectional study was conducted by taking 153 cord blood samples of full term newborns immediately after delivery in the hospital. Pre-term, still birth and emergency deliveries were excluded from the study. MATERIALS AND METHODS: The cord blood was collected and analysed for various Haematological parameters like Total leucocyte count, Absolute Neutrophil count, Immature to mature Neutrophil ratio, immature to mature ratio, Neutrophil morphology, nucleated erythrocytes, platelet count, micro erythrocyte sedimentation rate. Blood cultures were performed as gold standard for diagnosing neonatal sepsis. STATISTICAL ANALYSIS: Chi-square test, Risk ratio, risks in exposed and risk in unexposed were performed. RESULTS: Of 153 newborns for analysis, 59 (38.56%) developed sepsis. The haematological scoring system found that an abnormal immature to total neutrophil ratio, Neutropenia, micro erythrocyte sedimentation rate followed by an abnormal immature to mature neutrophil ratio were the most sensitive indicators in identifying infants with sepsis. The study also found that higher the score, the greater the certainty of sepsis being present. CONCLUSION: The haematological scoring system using cord blood can be considered as an early predictive screening method for detection of early onset neonatal sepsis. Identifying the risk of developing sepsis early can prevent morbidity and mortality of the neonates.

The role of the gastrointestinal epithelium as a possible pathway for the transfer of nutrients to the embryo's circulation.

The endodermal cells of the human yolk sac (YS) produce non-nucleated erythrocytes (NNEs) and numerous serum proteins that are transiently storage within the YS cavity. After their transfer via the vitelline duct to the embryo gastrointestinal lumen, the nutrients' final fate is unknown. With the aim of investigate how erythroid cells and nutrients are conveyed to embryo circulation, we studied, using a morphological and immunohistochemical approach, the embryo anatomy and the serum protein α-fetoprotein (AFP) presence, in 15 human embryos and their YS, collected from tubal pregnancies from 4 to 8 wpf. We observed at 5 wpf, a strong AFP staining in the endodermal cells of the YS, thereafter AFP was only present in the YS cavity and the gastrointestinal lumen. During 7 wpf, AFP expression declined and disappeared, concomitant with YS regression. Between 5 and 7 wpf, NNEs were observed in the gastrointestinal cavity, where they accumulate in the stomach. Here, the cells were attached to the endodermal epithelial cells or were free in the lumen. By scanning electron microscopy, we identified signs of NNEs phagocytized by endodermal cells. Those NNEs free in the lumen, after hemolysis, were probably removed by endocytosis (cell debris). Taking all together, we postulate that after reaching the endodermal epithelial cells of the stomach, nutrients are transferred to the embryo by a phagocytic/endocytic mechanism that is operative until the end of 6 wpf. After absorption, NNEs are probably degraded within phagosomes, nutrients delivered to the cell cytoplasm and then transported towards the embryonic circulation.