Cytokine-Induced Killer Cells: A Unique Platform for Adoptive Cell Immunotherapy after Allogeneic Hematopoietic Stem Cell Transplantation

Background: Immunotherapies in general, and cellular immunotherapies, in particular are becoming increasingly integrated into current personalized cancer treatment, though still facing some obstacles in the allogeneic hematopoietic stem cell transplantation (HSCT) setting. Summary: The concept of isolating immune effector cells, expanding their numbers, enhancing their anticancer capabilities by modifying them without increasing their alloreactive potential is the mainstay of adoptive cellular immunotherapy after allogeneic HSCT. In this context, cytokine-induced killer (CIK) cells, a polyfunctional heterogenous population of conventional T cells, natural killer (NK) cells, and T-NK cells capable of using T cell and NK cell-like cytotoxicity mechanisms against a various cancers, showed minimal alloreactivity in pediatric and adult patients allografted for hematological malignancies. Furthermore, CIK cells have already shown compatibility with chemotherapy, different kinds of immune checkpoint inhibitors, epigenetic drugs, antibody-targeted therapies, and recently with chimeric antigen receptor-engineering techniques. Key Messages: Hence, CIK cell therapy represents a unique platform for adoptive cell immunotherapies, guiding innovative treatment approaches from preclinical research to future clinical trials for cancer patients with yet unmet medical needs. In this context, the allogeneic HSCT setting provides an alternative source for safe and efficient adoptive allogeneic CIK cell strategies against a variety of cancers.