title: Paediatric reference values for the peripheral T cell compartment.
abstract: Immunophenotyping of blood lymphocyte subpopulations is an important tool in the diagnosis of immunological and haematological diseases. Paediatric age-matched reference values have been determined for the major lymphocyte populations, but reliable reference values for the more recently described T lymphocyte subpopulations, like different types of memory T lymphocytes, recent thymic emigrants, regulatory T cells and CXCR5(+) helper T lymphocytes, are not sufficiently available yet. We determined reference values for the absolute and relative sizes of T lymphocyte subpopulations in healthy children using the lysed whole blood method, which is most often used in diagnostic procedures. When the absolute numbers of some or all T lymphocyte subpopulations fall outside these reference ranges, this may indicate disease. The reference values show the course of T lymphocyte development in healthy children. Absolute T lymphocyte numbers increase 1.4-fold during the first months of life, and after 9-15 months, they decrease threefold to adult values; this is mainly caused by the expansion of recent thymic emigrants and naive cells. Helper and cytotoxic T lymphocytes show the same pattern. Regulatory T cells increase in the first 5 months of life and then gradually decrease to adult values, although the absolute numbers remain small. The relative number of CXCR5(+) cells within the CD4(+) CD45RO(+) T lymphocytes increases during the first 6 months of life and then remains more or less stable around 20%.
authors.affiliation: Department of Pediatrics, Jeroen Bosch Hospital, `s-Hertogenbosch, The Netherlands.
authors.forename: E J H
authors.initials: EJ
authors.lastname: Schatorjé
authors.forename: E F A
authors.initials: EF
authors.lastname: Gemen
authors.forename: G J A
authors.initials: GJ
authors.lastname: Driessen
authors.forename: J
authors.initials: J
authors.lastname: Leuvenink
authors.forename: R W N M
authors.initials: RW
authors.lastname: van Hout
authors.forename: E
authors.initials: E
authors.lastname: de Vries
mesh_terms: D000293:Adolescent; D002451:Cell Compartmentation; D002648:Child; D002675:Child, Preschool; D006801:Humans; D007156:Immunologic Memory; D007223:Infant; D007231:Infant, Newborn; D018655:Lymphocyte Count; D012016:Reference Values; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*