T cell therapy after allogeneic stem cell transplantation : titration of IL-2 concentration when expanding cord blood t lymphocytes with and without IL-7, in order to optimize expansion protocol for donor lymphocyte infusion

Abstract

Umbilical cord blood (UCB) is a promising, increasingly used option for allogeneic stem cell transplantation. Among the beneficial features are availability, permissiveness regarding human leukocyte antigen (HLA)-matching, and low incidences of graft-versus-host disease (GVHD). A great disadvantage is the low cell number in the grafts and therefore insufficient T cell numbers to prepare for donor lymphocyte infusion (DLI). Expansion of cord blood cells in vitro has been conducted to solve this obstacle, and in this paper we present an attempt to optimize the expansion protocol used by Okas et al. for expansion of T cells for DLI. By using different culture conditions in five UCB derived T cell expansions, the results showed propitious effects of interleukin (IL)-7 and that an IL-2 concentration of 100-200 IU per ml medium induce the most effective expansion of T cells.