The present invention relates to a composition for expanding lymphocytes comprising at least two types of cytokines selected from interleukin 2 (IL-2), interleukin 15 (IL-15) and interleukin 21 (IL-21). It further relates to a Method of preparing a population of clinically relevant lymphocytes, comprising the steps of: obtaining a body sample from a mammal in particular a tissue sample or body liquid sample, comprising at least one lymphocyte and optionally separating the cells in the body sample, culturing the body sample in-vitroto expand and/or stimulate lymphocytes in the sample wherein the culturing comprises using IL-2, IL-15 and/or IL-21, and optionally determining the presence of clinically relevant lymphocyte in the cultured sample.The present invention also relates to an immunotherapy and the population of clinically relevant lymphocytes.
