In patients with Chediak–Higashi syndrome ...

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Jul 16, 2007 - does adding etoposide to the conditioning regimen improve the outcome? Bone Marrow Transplantation advance online publication,.
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LETTER TO THE EDITOR

In patients with Chediak–Higashi syndrome undergoing allogeneic SCT, does adding etoposide to the conditioning regimen improve the outcome? Bone Marrow Transplantation advance online publication, 16 July 2007; doi:10.1038/sj.bmt.1705774 Chediak–Higashi syndrome (CHS) is invariably fatal if left untreated; patients usually die during the accelerated phase, which in many ways resembles familial hemophagocytic lymphohistiocytosis (FHLH). Eapen et al.1 recently published the results of a multi-institutional study of 35 patients with CHS who underwent allogeneic stem cell transplantation (SCT); they reported an overall survival rate of 62%. This survival rate is comparable to that reported in patients with FHLH post-allogeneic SCT as shown recently by Ouache´e-Chardin et al.2 in a group of 58 FHLH patients, where the patients received etoposide in addition to busulfan and cyclophosphamide in the preparative regimen; the overall survival rate was 58.5%. In the study by Eapen et al.,1 the combination of busulfan and cyclophosphamide was the most common preparative regimen, but some patients received etoposide in addition; the authors correlated the survival and disease status post-SCT with some pre-transplant factors such as disease status pre-transplant and donor type, but they did not address the impact of the conditioning regimen (namely with or without etoposide) on the outcome, although on the other hand the small number of patients in each group (with or without etoposide) in that study may not have allowed such an analysis. The success of etoposide in inducing remission in patients with familial hemophagocytic syndrome pre-SCT has been reproduced in patients with CHS experiencing accelerated phase;3 this led many transplanters to incorporate etoposide in the conditioning regimen for these patients. Haddad et al.4 reported 10 patients with CHS who underwent allogeneic SCT; 9 of them received etoposide for their conditioning as well as busulfan and cyclophosphamide; a total of 7 patients were alive and well at the time of the report. In the same way, we used busulfan, cyclophosphamide and etoposide at our institution on five patients with CHS who underwent allogeneic SCT between April 2001 and May 2005; two patients received antithymocyte globulins in addition. Three had fully matched donors (siblings), one had a one-antigen-mismatched donor (maternal aunt) and one received a one-antigenmismatched unrelated cord blood. Four patients presented with accelerated phase and were treated with etoposide and steroids, and all patients were in remission at the

time of SCT. Four patients engrafted; engraftment was documented by donor–recipient chimerism studies and ranged between 10 and 100% donor chimerism. One patient subsequently lost his graft and died of disease recurrence 14 months after SCT. There were two additional deaths; one was 7 months post-SCT because of sepsis, but the patient was in remission at the time of death, and one was in the recipient of the unrelated cord blood who died of intracranial hemorrhage on day 38 post-SCT before engraftment. Two patients remain alive and free of disease at 5.5 and 4 years, respectively. Obviously, our numbers are also too small to make any solid conclusion about the effect of etoposide on the eventual results. Therefore, although etoposide had a dramatic impact on the management of the accelerated phase in CHS patients, its role in the conditioning of such patients before allogeneic SCT is yet to be validated; in fact, the rarity of the disease would be a major limitation for any study trying to address this issue, and thus the answer to this question remains elusive. M Ayas1 and A Al-Ghonaium2 Section of Pediatric Stem Cell Transplantation, Department of Pediatric Hematology–Oncology, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia and 2 Section of Allergy and Immunology, Department of Pediatrics, King Faisal Specialist Hospital and Research Center (KFSHRC), Riyadh, Saudi Arabia E-mail: [email protected]

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References 1 Eapen M, Delaat CA, Baker KS, Cairo MS, Cowan MJ, Kurtzberg J et al. Hematopoietic cell transplantation for Chediak–Higashi syndrome. Bone Marrow Transplant 2007; 39: 411–415. 2 Ouache´e-Chardin M, Elie C, de Saint Basile G, Le Deist F, Mahlaoui N, Picard C et al. Hematopoietic stem cell transplantation in hemophagocytic lymphohistiocytosis: a single center report of 48 patients. Pediatrics 2006; 117: e743–e750. 3 Bejaoui M, Veber F, Girault D, Gaud C, Blanche S, Griscelli C et al. The accelerated phase of Chediak–Higashi syndrome. Arch Fr Pediatr 1989; 46: 733–736. 4 Haddad E, Le Deist F, Blanche S, Benkerrou M, Rohrlich P, Vilmer E et al. Treatment of Chediak–Higashi syndrome by allogenic bone marrow transplantation: report of 10 cases. Blood 1995; 85: 3328–3333.