Virus-Specific T Cells for Hematopoietic Stem Cell Transplantation

Abstract

During the period of T cell immune recovery after hematopoietic stem cell transplantation (HSCT), viral infections and reactivation are a major cause of morbidity and mortality. Adoptive immunotherapy using virus-specific T cells (VSTs) derived from virus-exposed or naive donors has emerged as an effective strategy to prevent viral complication early after HSCT. Early-phase clinical trials show that such VSTs can both prevent and treat viral infections in 70–90% of patients, are safe, and are well tolerated with no infusion-related adverse events and/or worsening of graft-versus-host disease. These clinical trials have a tremendous potential in preventing and treating viral infections post HSCT. The field of adoptive T cell therapy has made huge strides to overcome some of the challenges such as cumbersome manufacturing strategies, targeting multiple viral antigens, and making the T cell product widely available through third-party banks. A collaborative effort between academic centers and industry is likely to facilitate the broader implementation and accessibility of these novel therapies. It will also enable randomized phase 3 clinical trials to prove the efficacy of these T cell products in comparison to often expensive and ineffective pharmacotherapies. Here we review the current methods of VST generation, clinical results using VSTs in the HSCT setting, and applications of VSTs to treat viral-associated malignancies.