Age-related lymphocyte subset changes in the peripheral blood of healthy children - a meta-study

Background: Immunophenotyping is an important diagnostic tool for decision making in various diseases. Although clinical interpretation relies on measurable aberrations of the patient's values from normal ranges, age-dependent are rarely available. Materials and Methods: The present study is aimed to combine published data about normal values of peripheral blood lymphocyte subpopulations to describe age-dependent changes from the neonate to the adult. These values could serve in a better way as normal values in comparison to present ones. Furthermore, this investigation allows us to define valid data even for short periods in children's life and to investigate the influence of technical approaches, sample preparation, antibody selection, measurement equipment, and data analysis. Results: Development-related alterations of lymphocyte subset counts in children could be extracted from the pre-existing papers for diagnostic use. These results were mostly independent from gender, ethnic factors, procedure of sample collection, anticoagulation, pre-analytical procedures, time to workbench, applied method for immunophenotyping, staining procedure, selected monoclonal antibodies, technical devices, and software products. Conclusion: Our data indicate that previous normal values are not sufficiently precise for the interpretation of lymphocyte subsets in children. Mainly during the 1st year of life, count and subset distribution of lymphocytes is different from that of adults. Therefore, a close meshed data set of normal values is required to guarantee adequate diagnostic