Post-transplantation lymphoproliferative disorder of recipient origin in a boy with acute T-cell leukemia with detection of B-cell clonality 3 months before stem cell transplantation.

Post-transplantation lymphoproliferative disorder is an infrequent complication after hematopoietic stem cell transplantation. It is hypothesized that lack of T-cell surveillance following transplantation permits reactivation of latent EBV leading to polyclonal B-cell expansion and finally outgrowth of a predominant clone. Most cases are of donor origin. Here, we describe an 8-year old boy with early onset post-transplantation lymphoproliferative disorder following matched-unrelated stem cell transplantation for high-risk T-cell leukemia whose disease was unusual for two reasons. First, his B-cell clone was of host origin and, in contrast to the few PTLD of host origin described so far, not associated with autologous reconstitution. Secondly, using clonal analysis, we could retrospectively show that the B-cell clone emerged during consolidation chemotherapy for T-cell leukemia, 3 months before stem cell transplantation.