Mixed myeloid chimerism and relapse of myelofibrosis after allogeneic stem cell transplantation

Assessing response and confirming early relapse after transplant for MF is often challenging based on the clinical criteria,9 and it usually takes a few months for fibrosis to resolve and the bone marrow morphologic remission to be achieved.10 Detecting the JAK2 V617F mutation after SCT in MF is a strong predictor of relapse and a potential marker for guiding adoptive immunotherapy.7,1113 Few studies have focused on the potential role of mixed chimerism in predicting early relapse, particularly in those with mixed myeloid chimerism (MMC).14-18 The influence of MMC on posttransplantation relapse of MF has not been well studied. Therefore, we aimed to determine the role of MMC in predicting relapse in MF patients after allo-SCT. We further explored the correlation between myeloid chimerism and molecular relapse of MF. Eighty-two consecutive patients with primary or secondary MF who underwent their first allo-SCT at The University of Texas MD Anderson Cancer Center from January 2005 to July 2015 were identified. Patients with double cord or haploidentical donors or with primary graft failure were excluded. MF relapse was defined as any evidence of persistent or recurrent morphologic