Original Article
Reference values of leukocyte and lymphocytes populations in umbilical cord and capillary blood in healthy Mexican newborns

https://doi.org/10.1016/j.aller.2019.12.009Get rights and content

Abstract

Introduction

In newborns, dramatic changes occur in the blood and bone marrow during the first hours; there are rapid fluctuations in the quantities of leukocytes populations. In this work, we investigated leukocytes subsets counts in two types of blood samples (cord blood and capillary blood) extracted from healthy newborns.

Methods

Blood samples from Mexican neonates were collected by Instituto Nacional de Pediatría with written informed consent. For all samples we determined leukocytes populations; neutrophils, monocytes, total lymphocytes, and populations: T CD3+ cells, TCD4+ cells, T CD8+ cells, B CD19+ cells and NK CD16+56 cells by flow cytometry. We used the Mann–Whitney U test to compare leukocytes of cord and capillary blood; also to analyze the differences between gender and we obtained reference values of the cord and capillary blood in neonates.

Results

We observed higher absolute counts and frequencies of total lymphocyte in capillary blood compared with cord blood. In absolute numbers, the capillary blood showed significant differences in neutrophils, monocytes, lymphocytes, T CD3+ cells, T CD4+ cells, T CD8+ cells, B CD19+ cells, and NK cells; no significant differences were observed between genders.

Discussion

Our data contribute to newborn Mexican reference values for all these populations of leukocytes. We found that the dispersal range differs between the two types of blood, suggesting a different fate in the immune response. Immunophenotyping of the blood cell population to identify these cells is an essential tool in the diagnosis and follow-up of neonates with immunodeficiencies and other immune disorders.

Introduction

The development of the human immune system begins early in the fetal period, but it is not completed at birth; post-natal maturation proceeds for months to years, even into adulthood. Neonates have little immunological memory and a developing immune system, which increases their vulnerability to infectious agents.1

Umbilical cord blood is the blood left over in the placenta and the umbilical cord after the birth of the baby. The cord blood is composed of all the elements found in whole blood; it contains red blood cells, white blood cells, plasma, platelets and is also rich in hematopoietic stem cells.2

The blood vessels are the part of the circulatory system, and microcirculation, that transports blood throughout the human body. Capillary blood sampling via a heel lance is the most common procedure performed in hospitalized neonates, capillary blood obtained by skin puncture is from a dynamic tissue fluidic system that contains circulating capillary blood, interstitial fluid and lymphatic fluid.3

Blood is a complex tissue consisting of a very specialized network of circulating immune cells. The compartments of first-line innate immune response and adaptative response are essential to protect from a wide variety of pathogens. Dysregulated immune response can lead to an increased susceptibility to infection, primary immunodeficiency, autoimmune diseases or cancer.4 Both genetic and non-genetic factors may contribute to variations in the number of human immune cells. It is also possible that different linages have different fluctuations in accordance with varied environmental and nutritional states.5 It is therefore important to have reference values for varied ethnic-geographic populations.

Immunophenotyping of blood lymphocyte subpopulations is an essential tool in the diagnosis and follow-up of children with immunodeficiencies, hematological diseases, and other disorders. Studies of leukocytes from preterm newborns have been limited, and there is little information available concerning the development and function of the innate immune system depending on the gestational age of newborns. Preterm infants, due to the immaturity of the immune system, are at a heightened risk of acquisition of recurrent bacterial infection during their first weeks of life, due to frequent exposure to the micro-organism, frequently, invasive procedures such as catheterization and intravascular or assisted ventilation need to be done in order to treat these infections.6, 7

In this work, we investigated the counts of leukocytes subsets in two types of blood samples (cord blood and capillary blood) extracted from healthy newborns to establish reference ranges that may be helpful to the pediatricians to determine possible alterations in these cell subsets. To this, we have performed flow cytometric phenotyping to determine values reference and studied whether there are differences between genders.

Our data further show that the extent of dispersal between individuals varies widely for different blood leukocyte subsets.

Section snippets

Study subjects

Cord Blood was collected from full-term neonates from healthy mothers delivered by normal vaginal delivery. Neonates who had any maternal antenatal risk factors were excluded. Immediately after delivery, 1 ml of cord blood was collected from the umbilical cord vein by venipuncture at the cut end of the cord attached to the placenta. Additionally, 1 ml of capillary blood was collected by heel-prick. The blood samples were collected in tubes with anti-coagulated with ethylenediamine tetraacetic

Statistical analysis

Statistical analyses were performed using GraphPad Prism, version 5.0 (GraphPad Software Inc., La Jolla, CA, USA). Two-group comparisons were performed using the Mann–Whitney test. Stratified data were expressed as the mean value. The results were expressed as the median, and p-values <0.05 were considered to be significant. The normal reference values of cord and capillary blood were defined as 5–95 percentiles, and the median rank was shown at the same time.

Characteristic of a healthy newborn

A total of 50 pregnant women visiting the clinic met the inclusion criteria at the time of delivery and gave consent for the collection of the cord blood and capillary blood from their newborn. The study is part of a protocol approved by the local ethics committee of number 061/2010, which were developed according to the rules declared under the Declaration of Helsinki. The demographic data of the 50 neonates includes: gender 21 female and 28 male; average gestation age at birth in weeks was

Discussion

A newborn represents the culmination of developmental events from conception, implantation, and organogenesis. Dramatic changes occur in the blood and bone marrow of the newborn infant during the first hours and days after birth, and there are rapid fluctuations in the quantities of all hematologic elements. Neonates process a developing immune system, which is different from adults, additionally, neonates are highly susceptible to infections since they change from a semi-allogeneic sterile to

Conflicts of interest

The authors have no conflict of interest to declare.

Acknowledgments

The authors wish to thank Dr. Rafael Figueroa Moreno for technical assistance. This study was partially supported by grants from Consejo Nacional de Ciencia y Tecnología CONACyT (project CB-2016-256471), Ciudad de México, México.

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