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

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.

[Perinatal risk factors for mortality in the high-risk newborn]. / Factores de riesgo perinatal para mortalidad en el neonato de alto riesgo.

This study was to determine the risk factors for mortality in a cohort of neonates in a neonatal intensive care unit. Comparative study of the perinatal antecedents between lives and deaths, calculating risk factors for mortality by the chi square test, with Mantel and Haenzel corrected and bivariate analysis. We studied 425 neonates with, weight and age of gestation 1640 +/- 359 gr. and 32 +/- 2 weeks (X and SD), all required assisted mechanical ventilation during 10 +/- 12 days, and stayed in NICU 13 +/- 12 days. The risk factor for mortality were (p < 0.05); gesta IV, < 1 abortion previously, premature rupture of placenta, premature rupture of membranes with chorioamnionitis, pelvic delivery for vaginal via, age of gestation < 28 weeks, birth weight < 1,000 gr., septic shock, metabolic acidosis, acute renal failure, neonatal necrotizing enterocolitis and air leak. In this group of high risk neonates, for the prenatal, neonatal and postnatal antecedents, we find 12 risk factors for mortality; four attributed to the pregnancy, on to the delivery and seven for problems of the neonate.