The aim was to evaluate the feasibility of donor lymphocyte infusion (DLI) in transplanted patients with thalassemia who were at imminent risk of graft rejection (GR).Procedure.
We retrospectively evaluated outcomes in a cohort of 19 patients with thalassemia who received DLI following 21 transplantations. Patients were divided into three groups depending on indication and time of DLI: group I, mixed chimerism-level-3 (MC-level-3) within 2 months and subsequently receiving DLI; group II, MC-level-3 within 2 months and receiving deferred DLI beyond post-transplant 2.5 months; group III, receiving DLI because of a gradual decrease in both donor cells and hemoglobin levels without MC-level-3 within 2 months.Results.
Three patients evolved to compete chimerism (16%), 9 patients had MC with transfusion independency (47%) and 7 had GR (37%). Three of 7 patients in group I, 1 of 4 patients in group II and 8 of 10 patients in group III preserved the graft. Although significant increases in the percentage of donor cells were not detected in group III, hemoglobin levels improved (median, 6.8–8.8 g/dl, P = 0.002).Conclusion.
The risk of GR is high in patients with thalassemia who have MC-level-3 within 2 months after transplantation. DLI is a feasible method for converting unstable MC towards stable MC or full donor chimerism, but its efficacy is partially related to the percentage of residual host cells at the time of infusion. Serial chimerism studies can identify unstable MC earlier and may guide the proper timing of intervention. Pediatr Blood Cancer 2012; 58: 453–458. © 2011 Wiley Periodicals, Inc.