Extended immunophenotyping reference values in a healthy pediatric population

Abstract

Background For the accurate diagnosis of immunodeficiencies is crucial to compare patients’ immunology laboratory values with age‐sex matched controls, yet there is a paucity of normal values for most populations. Objectives To define appropriate reference values of extended lymphocyte subpopulations and T‐cell receptor excision circle (TRECs) levels in healthy pediatric donors between 1 month and 18 years of age. Methods Extended immunophenotyping values were obtained by analysis of multiparameter flow cytometry panels for the following subpopulations: CD4+ and CD8+ Naive, Effector, Effector Memory and Central Memory, T helper subpopulations and their degrees of activation, T Regulatory cells, Recent Thymic Emigrants (RTE), B Lymphocyte subpopulations (Transitional, Naive, Preswitch‐Memory, Switch‐Memory, Plasmablasts, CD21low, and Exhausted), and subpopulations for Monocytes, NK cells and Dendritic Cells. Results Median values and the 10th and 90th percentiles were obtained for 32 lymphocyte and monocyte subpopulations, and for TRECs levels in each age group of children. Naive CD4+ and CD8+ T‐cell populations tended to decrease with age, with significant difference between the groups, in parallel with the reduction in thymic function assessed by TRECs counts and the recent thymic emigrant population. Relative numbers of Th cell populations tended to increase with age. The percentage of class‐switched B cell populations showed a significant increase between the youngest group and the others. Conclusion This study provides essential data for interpreting extended immunophenotyping profiles in the pediatric and young adult populations, which could be of value for the diagnosis of PIDs and immune‐mediated diseases, particularly those associated with subtle immunological abnormalities. © 2018 International Clinical Cytometry Society

Thymic output changes in children with clinical findings signaling a probable primary immunodeficiency

“…Demographic and general laboratory data for all patients are given in Table I. 15,16 In whole patient group, immunoglobulin G, A and M values were low in 64.6%, 33.8% and 40% of the patients, consequitively. CD3 + T-cell percentages were low in 36.4% and CD19 + B-cell percentages were low in 22.7% of the patients.…”

The IL-2RG R328X nonsense mutation allows partial STAT-5 phosphorylation and defines a critical region involved in the leaky-SCID phenotype

“…A complete loss‐of‐function mutation in IL2RG leads to an arrest of lymphocyte development, resulting in the typical X‐SCID T – B + NK – phenotype, whereas patients with hypomorphic mutations often show some T and NK cells, although usually in a reduced number due to partial functioning of γ c , which allows cell development through IL‐7 and IL‐15 signaling . The three patients carrying the R328X mutation described to date had low T cell counts and normal or even increased NK cell counts, resulting in an atypical leaky SCID phenotype (Table ).…”

“…Circulating lymphocyte subpopulations were extensively immunophenotyped by flow cytometry, as previously described . To study expression of CD132 (γ c ), 50 µl of EDTA blood was stained with CD132‐phycoerythrin (PE) [Becton Dickinson (BD), Franklin Lakes, NJ, USA], CD127‐allophycocyanin (APC) (BioLegend, San Diego, CA, USA) and CD3 Pacific Blue (BD).…”

Issue Highlights – May 2019

“…This is particularly true in children, due to the high dynamics observed after birth, particularly during the first years of life and the relatively limited number of cell populations (particularly within T‐cells) for which reference ranges have been established during childhood in the literature. Garcia‐Prat et al provide reference values for >30 lymphocyte, monocyte and dendritic cell subsets in blood, based on a cohort of 159 children with an age range of between 1 month and 18 years. Interestingly, a progressive decrease in subsets of recently‐produced thymic emigrants and naïve T‐cells and total B‐lymphocytes, together with progressive increase in (distinct subsets of) T‐helper cells was found.…”