Use of belatacept as alternative graft vs host disease prophylaxis in pediatric allogeneic hematopoietic stem cell transplantation

A Difficult Case of Calcineurin Inhibitor Neurotoxicity Post-Haploidentical HCT With a Successful Novel Solution: Cytotoxic T-Lymphocyte-Associated Protein 4-Immunoglobulin Blockade for GVHD Prophylaxis

Post-allogeneic hematopoietic cell transplant (HCT) immunosuppression regimens are given as graft-versus-host disease (GVHD) prophylaxis. Most GVHD prophylaxis regimens are based on calcineurin inhibitors (CNIs). Unfortunately, CNIs are associated with significant associated morbidity, frequently cannot be tolerated, and often need to be discontinued. There is no consensus as to which alternative immunosuppression should be used in cases where CNIs have to be permanently discontinued. Cytotoxic T-lymphocyte-associated protein 4-immunoglobulin (CTLA4-Ig) blocking agents are well tolerated and have been used extensively in patients with autoimmune disease and as post-transplant immunosuppression. There are two CTLA4-Ig agents: belatacept and abatacept. Belatacept is routinely used in adult kidney transplantation to prevent rejection and abatacept has been approved by the Food and Drug Administration (FDA) for GVHD prophylaxis in patients undergoing a matched or one allele-mismatched unrelated allogenic HCT. Herein, we describe a case in which abatacept was given off-label to replace tacrolimus GVHD prophylaxis in a patient with neurotoxicity undergoing haploidentical HCT. This case suggests that CTLA4-Ig blockade may be a good alternative to a CNI in cases where the CNI needs to be discontinued and warrants further investigation.

T-lymphocyte depleted transplants for inborn errors of immunity

INTRODUCTION

Hematopoietic stem cell transplantation is a curative treatment for many inborn errors of immunity (IEI). Incremental improvements and advances in care have led to high rates of >85% survival and cure in many of these diseases. Improvements in HLA-classification and matching have led to increased survival using HLA-matched donors, but survival using T-lymphocyte-depleted mismatched grafts remained significantly worse until fairly recently. Advances in T-lymphocyte depletion methods and graft engineering, although not specific to IEI, have been widely adopted and instrumental in changing the landscape of donor selection, such that a donor should now be possible for every patient.

AREAS COVERED

A literature review focusing on T-lymphocyte depletion methodologies and treatment results was performed. The importance of early T-lymphocyte immunoreconstitution to protect against viral infection is reviewed. Two main platforms now dominate the field - immune-magnetic selection of specific cell types and post-transplant chemotherapeutic targeting of rapidly proliferating allo-reactive T-lymphocytes - the emerging literature on these reports, focusing on IEI, is explored, as well as the impact of serotherapy on early immunoreconstitution.

EXPERT OPINION

Pharmacokinetic monitoring of serotherapy agents, and use of co-stimulatory molecule blockade are likely to become more widespread. Post-transplant cyclophosphamide or TCR depletion strategies are likely to become the dominant methods of transplantation for nonmalignant diseases.