Clinical strategies to enhance posttransplant immune reconstitution

This is not the end. It s not even the beginning of the end. But it is, perhaps, the end of the beginning. Sir Winston Churchill Immune reconstitution after hematopoietic stem cell transplantation (HSCT) has been well studied in the mouse and humans, and the relationship between delayed immune reconstitution and posttransplant morbidity and mortality from infections and relapse has been well documented [1]. Whereas erythroid, myeloid, and platelet reconstitution occurs in most cases in the first weeks after HSCT and is primarily determined by engraftment of donor HSCs, B cell, and especially T cell reconstitution takes much longer, and recipients of allogeneic HSCT can have an impaired T and B cell function even years after their HSCT [2]. In recent years a number of strategies to enhance posttransplant immune reconstitution have been developed and successfully tested in preclinical models. These studies in experimental models mark the end of the beginning, and in this article we will discuss the first attempts to introduce these strategies in clinical trials with HSCT recipients.