[Successful second cord blood transplantation (CBT) for late graft failure associated with several immune disorders after the initial CBT in a patient with acute myeloid leukemia].

A 64-year-old woman underwent reduced-intensity conditioning cord blood transplantation (RIC-CBT) for refractory acute myeloid leukemia (AML). A 6/6 antigen-level HLA-identical cord blood from a male infant was transfused. After successful engraftment with complete donor chimerism, the patient developed mixed chimera (XX 8.8%) on day 82. Tapering of tacrolimus was started on day 96. Bone marrow chimerism analysis showed a decreasing recipient cell population (XX 2.2%) on day 117 and tacrolimus was discontinued with no clinical signs of GVHD on day 123. However, pancytopenia with agranulocytosis was detected on day 138. She was diagnosed as having secondary graft failure associated with Coombs-positive immune hemolytic anemia and immune thrombocytopenia (ITP). At the same time, the percentage of recipient T cell chimerism in peripheral blood was about 50% and the B cell population showed lambda light chain restriction. On day 180, she received a second RIC-CBT due to lack of improvement of agranulocytosis. A single dose of rituximab was administered on day - 11 before the second CBT to eliminate the activated B cells. Prompt neutrophil engraftment was achieved and both hemolytic anemia and ITP also showed resolution. She is currently well (30 months after the second CBT), showing normal blood cell counts and complete second donor chimerism of marrow cells.