1. ¹Paediatric Haematology and Oncology, Johann-Wolfgang-Goethe University, Frankfurt, Germany
2. ²Competence Centre of Statistics and Operation Research, University of Applied Sciences, Frankfurt, Germany

Correspondence: Dr U Koehl, Laboratory of Stem Cell Transplantation and Immunotherapy, Paediatric Haematology and Oncology, Johann-Wolfgang-Goethe University, Theodor Stern Kai 7, 60596 Frankfurt, Germany. E-mail: koehl@em.uni-frankfurt.de

Received 8 September 2006; Revised 27 November 2006; Accepted 18 December 2006.

Abstract

To evaluate the correlation between kinetics of immune reconstitution and survival, we prospectively evaluated lymphocyte subsets in 32 paediatric patients undergoing allogeneic stem cell transplantation (SCT) for haematological malignancies. Four-colour flow cytometric analysis was performed at short intervals with a median follow-up of 4 years post SCT. A total of 50% of patients reached age-matched 5th percentile of natural killer, cytotoxic T, B and helper T cells 4, 9, 20 and 28 weeks after SCT, respectively, which increased to more than 80% within 1 year after SCT. Transplantation of peripheral blood stem cells (PBSC) seemed to elicit the fastest reconstitution of CD3⁺, CD4⁺CD3⁺, CD8⁺CD3⁺ and naïve T cells compared to bone marrow (BM) or CD34-selected PBSC, which did not differ. Most importantly, we observed a significantly higher number of survivors among patients whose CD8⁺CD3⁺ absolute counts rose above the 5th percentile of age-matched normal levels during the first year post SCT compared to patients who never reached these levels (19/25 vs 0/7, P<0.001). This was still present in both subgroups, BM- and CD34-selected grafts (P=0.03, 0.02). These results from a small patient sample underline the importance of particular lymphocyte subsets for the outcome of children undergoing SCT. A larger study with detailed subset analysis is underway.