Cellular immunotherapy for hematological malignancy: recent progress and future perspectives

Advancements in the field of cellular immunotherapy have accelerated in recent years and have changed the treatment landscape for a variety of hematologic malignancies. Cellular immunotherapy strategies exploit the patient's immune system to kill cancer cells. The successful use of CD19 chimeric antigen receptor(CAR) T-cells in treating B-cell malignancies is the paradigm of this revolution, and numerous ongoing studies are investigating and extending this approach to other malignancies. However, resistance to CAR-Tcell therapy and non-durable efficacy have prevented CAR-T-cells from becoming the ultimate therapy. Because natural killer(NK) cells play an essential role in antitumor immunity, adoptively transferred allogeneic NK and CAR-modified NK cell therapy has been attempted in certain disease subgroups. Allogenic hematopoietic stem cell transplantation(allo-HSCT) is the oldest form of cellular immunotherapy and the only curative option for hematologic malignancies. Historically, the breadth of application of alloHSCT has been limited by a lack of identical sibling donors(ISDs). However, great strides have recently been made in the success of haploidentical allografts worldwide, which enable everyone to have a donor. Haploidentical donors can achieve comparable outcomes to those of ISDs and even better outcomes in certain circumstances because of a stronger graft vs. tumor effect. Currently, novel strategies such as CAR-T or NK-based immunotherapy can be applied as a complement to allo-HSCT for curative effects, particularly in refractory cases. Here, we introduce the developments in cellular immunotherapy in hematology.