1. ¹Pediatric Immunohematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute, Milan, Italy
2. ²San Raffaele Telethon Institute for Gene Therapy (HSR-TIGET), Milan, Italy
3. ³Hematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute, Milan, Italy
4. ⁴Vita-Salute San Raffaele University Medical School, Milan, Italy

Correspondence: Dr S Marktel, Pediatric Immunohematology and Bone Marrow Transplantation Unit, San Raffaele Scientific Institute, via Olgettina 60, Milano 20132, Italy. E-mail: marktel.sarah@hsr.it

Received 23 April 2009; Revised 28 August 2009; Accepted 13 September 2009; Published online 2 November 2009.

Abstract

Mixed chimerism (MC) and secondary graft failure are frequent events following SCT for thalassemia. There is limited information regarding the outcome of donor lymphocyte infusion (DLI) to prevent rejection, mainly from case reports describing only successful cases. We describe a series of seven children affected by -thalassemia treated with escalating doses of DLI for level 2–3 MC (donor<90%) following myeloablative SCT from a matched family donor. The infusions were safe and no acute or chronic GVHD were documented; five patients experienced neutropenia and thrombocytopenia resolving spontaneously. DLI was successful in converting to full donor chimerism two patients stratified in the low-risk class (Pesaro class II). Conversely, for five high-risk patients, DLI was not effective in preventing secondary graft failure. This limited series suggests that escalating doses of DLI are safe in thalassemia patients post myeloablative therapy but efficacy may be jeopardized by rapidly growing anti-donor alloimmunity in high-risk patients. We suggest giving escalating doses of donor T cells to attempt a graft-versus-thalassemia as soon as level 2–3 MC is detected.