Abstract: The present invention provides a method of identifying sub-populations of cells in a cellular sample. Aspects of the method include categorizing cells of the cellular sample into at least a first and second population based on a first phenotypic property. The method may further include sub-categorizing each of the first and second population into sub-populations of cells based on a second and third phenotypic property, e.g., by using X detectable labels providing Y distinct signals, wherein X>Y, to identify sub-populations of cells in the cellular sample.

Abstract: A method for the identification of regulatory T cells based on the diminished abundance or even absence of the global gene regulator SATB1 in such regulatory T cells. In particular, the invention relates to a method utilizing ligands that specifically bind to SATB1 for identifying regulatory T cells which are cells showing a reduced binding to said ligand. Such method is suitable for quality determination of a regulatory T cell population. A kit or diagnostic composition for such method is also disclosed.