Haploidentical Hematopoietic Cell Transplantation With Post‐Transplant Cyclophosphamide for Pediatric Chronic Active Epstein–Barr Virus Infection

Hematopoietic cell transplantation (HCT) is the only curative treatment for chronic active Epstein-Barr virus infection (CAEBV). While HCT is needed at the appropriate time, there are sometimes difficulties in securing an appropriate donor, making HLA haploidentical donor an alternative option. Recently, post-transplant cyclophosphamide (PTCy) has rapidly gained popularity as a safe graft-versus-host disease (GVHD) prevention strategy for HCT from HLA haploidentical donors; however, there are only a few reports of its use for CAEBV. A retrospective chart review was completed for two pediatric CAEBV cases who underwent HLA haploidentical HCT (Haplo-HCT) with PTCy. A 6-year-old girl diagnosed with CAEBV previously underwent HCT twice from an HLA 8/8 matched brother, which both failed due to secondary graft failure. A third HCT was planned with a peripheral blood stem cell from her haploidentical father. She received a busulfan-based reduced intensity conditioning regimen. PTCy, mycophenolate mofetil, and tacrolimus were used for GVHD prophylaxis. Engraftment was achieved with full donor chimerism, and she remained in complete remission. A 7-year-old girl also diagnosed with CAEBV underwent HCT from her haploidentical mother with the same conditioning regimen and GVHD prophylaxis as the previous case. Engraftment was achieved with full donor chimerism. She suffered grade II (skin stage 3) acute GVHD and transplant-associated thrombotic microangiopathy, which were both treated successfully. She remained in complete remission. Haplo-HCT with PTCy was safely performed for two pediatric CAEBV patients. Haplo-HCT may be a useful transplant option for CAEBV patients without a matched donor option.