1. ¹Department of Paediatrics, Emma Children's Hospital, Academic Medical Center, Amsterdam, The Netherlands
2. ²Department of Immunology/BMT, Wilhelmina Children's Hospital, Utrecht Medical Center, Utrecht, The Netherlands
3. ³Willink Biochemical Genetics Unit and Department of Haematology/BMT, Royal Manchester Children's Hospital, Manchester, UK
4. ⁴Department of Haematology and Oncology, Our Lady's Hospital for Sick Children, Dublin, Ireland
5. ⁵Department of BMT, Great Ormond Street Hospital, London, UK

Correspondence: Dr J-J Boelens, Department of Immunology/BMT, Wilhelmina Children's Hospital, Utrecht Medical Center, KC 030-63.0, PO Box 85090, Utrecht 3508 AB, The Netherlands. E-mail: J.J.Boelens@umcutrecht.nl

⁶These authors contributed equally to this work.

Received 8 February 2006; Revised 21 April 2006; Accepted 21 April 2006; Published online 22 May 2006.

Abstract

Hurler syndrome (MPS 1H) is the severe form of mucopolysaccharidosis type 1 (MPS 1). Haematopoietic cell transplantation (HCT) is the treatment of choice, but carries a high incidence of graft failure and morbidity. The use of enzyme replacement therapy (ERT) might improve the clinical signs and symptoms before HCT, resulting in less transplantation-related complications. Moreover, clearance of glycosaminoglycans (GAG's) from the bone marrow might improve engraftment. Twenty-two patients with MPS 1H received one or more HCT procedures in combination with ERT. One patient with severe cardiomyopathy improved significantly after ERT. All children were in a relatively good clinical condition before HCT. Of patients 59, 82 and 86% were alive and engrafted after one, two and three HCT procedures, respectively. Two patients died after repetitive HCT. No serious ERT-infusion-related toxicity occurred. ERT with HCT was well tolerated. Neither a positive nor a negative effect on the number of patients who are alive and engrafted after receiving ERT before HCT as compared to a historic cohort was noted. However, patients in a poor clinical condition before HCT might benefit from ERT.