Avaliação do perfil fenotípico de células t, b e nk em recém-nascidos a termo e pré-termo

Abstract

Introduction: The proper development of the cellular component of the acquired immune system during pregnancy may be influenced by its duration. This development can be evaluated at birth by quantitative and qualitative cytological analysis of immune cells by flow cytometry, which is able to quantify and analyze the physical, chemical and biological characteristics of the immune cells subpopulations. Objective: The study aimed to look for reference values for T, B and NK cells in newborns at term. Furthermore, the values of 38 newborn term samples were compared with 8 preterm newborn samples, in order to determine whether there was or not statistically significant differences between these groups. Methods: Blood samples of 46 healthy newborns were obtained, with 38 full-term and 8 preterm, which were subjected to lysis of red blood cells, washing with saline, centrifuging and discarding the supernatant with addition of conjugated monoclonal antibodies fluorophores. Subsequently, the acquisition of cell groups from each sample was performed using a flow cytometer, using analysis software and determination of the percentage values of T, B and NK cells regarding the percentage of total lymphocytes, and then calculated the absolute values of cell groups and then made a comparison between groups of full-term and preterm newborns. Results: We determined the reference values of the subpopulations of T, B and NK cells for newborns at term and carried out a comparative analysis between reference values of newborns at term and preterm, which showed no statistically significant differences, although the values for the 25th and 75th percentiles of the medians have showed a slight predominance of T CD4+ and CD8+, B and NK cells in the group of term newborns. Conclusion: Reference values found for newborns at term were mostly similar to those found in the literature. Furthermore, the study concluded that the results show a small difference between the values for newborns at term and preterm, however, due to limited sample size, we cannot say if there is or not a significant difference between these two groups.