Reference Values For Peripheral Blood Lymphocyte Subsets Of Healthy Children And Its Application In Primary Immunodeficiency Disease:A Multi-centered Study

Background: Defining abnormality in the distribution of peripheral blood lymphocyte populations is key to the diagnosis of primary immunodeficiency and numerous other immune disorders in childhood.To do so requires reference to expected normal values derived from a sufficiently large sample of healthy children of various ages,who preferably are also from the same region.Objective: Use of domestic reference values is known to improve the accuracy of flow cytometric analysis by integrating local variation due to race,gender,and age.As there are currently none available,our aim was to establish the reference values for peripheral blood lymphocyte phenotypes in healthy Chinese children.Methods: Peripheral blood samples were taken from 1075 children aged 0-18 years(stratified into seven age groups,which contained 21-289 samples),and the relative proportion and absolute numbers of 20 lymphocyte subsets were determined by means of seven-color flow cytometry.Relative and absolute sizes of each subset were calculated.When absolute numbers were concerned,a dual platform approach was used.Results: We determined age-related reference values for the following lymphocyte subsets: total T cells;CD4(helper)and CD8(cytotoxic)T cells;the na?ve,central memory,effector memory,and terminal effector memory subsets within both helper and cytotoxic T cell populations;TCR?? double negative T cells;??T cells;NK cells;total B cells;and the na?ve,memory,transitional,and plasmablast B-cell subsets.We found that the distributions of lymphocyte subsets changed by age.We detected these subsets in PID patients such as WAS,ALPS,and found some clues in PID diagnosis.Conclusion: This study provides the largest analysis of peripheral blood lymphocyte subsets in healthy children.The reference values reflect the continuous maturation of lymphocyte subsets during childhood.The reference values presented are likely to be especially appropriate for clinical evaluation of immune abnormalities in Chinese children.