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 9-15months, 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 5months 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 6months of life and then remains more or less stable around 20%.,
Scandinavian Journal of Immunology
Department of Pediatrics

Schatorjé, E.J.H, Gemen, E.F.A, Driessen, G.J.A, Leuvenink, J, Hout, R.W.N.M, & de Vries, E. (2012). Paediatric Reference Values for the Peripheral T cell Compartment. Scandinavian Journal of Immunology, 75(4), 436–444. doi:10.1111/j.1365-3083.2012.02671.x