2020 Volume 9 Issue 1 Pages 13-22
Monoclonal antibodies blocking the immune checkpoints such as programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA-4) on T cells enhance anti-tumor immunity and are employed in the treatment of various malignant tumors, including relapsed/refractory classical Hodgkin’s lymphoma (cHL). Though immune checkpoint blockade in the context of allogeneic hematopoietic stem cell transplantation (allo-SCT) could potentiate donor anti-tumor responses, it possibly develops severe graft-versus-host disease (GVHD) as well. In preclinical mouse models, the blockade of both CTLA-4 and PD-1 after allo-SCT develops severe GVHD. In a clinical setting, allo-SCT in patients with prior history of anti-PD-1 treatment leads to acute GVHD and a non-infectious febrile syndrome that requires the use of corticosteroids. Because the administration of PD-1 inhibitors after allo-SCT also leads to acute GVHD, it is recommended that PD-1 inhibitors should be started at a low dose against relapsed cHL post-allo-SCT. In this review, recent advances in understanding of the immunological effects and clinical outcomes of checkpoint blockade in the context of allo-SCT are summarized. Moreover, monitoring of anti-PD-1 monoclonal antibodies on T cells that could estimate the effects of PD-1 inhibitors are also discussed.