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Immune reconstitution and outcome after unrelated cord blood transplantation: a single paediatric institution
P Giraud1, I Thuret, D Reviron
1Service d'Hématologie Pédiatrique, Hôpital Timone Enfants, Marseille, France.
Insights
Unrelated cord blood transplant (U-CBT) in children showed a 67% event-free survival. Immune reconstitution revealed prompt B cell recovery but delayed T cell recovery in the first year post-transplant.
Area of Science:
- Hematology
- Immunology
- Pediatric Oncology
Background:
- Unrelated cord blood transplant (U-CBT) is a critical therapeutic option for pediatric hematologic malignancies.
- Understanding immune reconstitution post-U-CBT is vital for optimizing patient outcomes and managing complications.
Purpose of the Study:
- To evaluate the outcomes and immune reconstitution following U-CBT in pediatric patients.
- To analyze lymphocyte subset recovery, including B cells, NK cells, and T cell subsets, within the first year post-transplant.
Main Methods:
- Retrospective analysis of 12 children undergoing U-CBT between February 1997 and July 1998.
- Assessment of immune reconstitution through lymphocyte subset counts (total lymphocytes, B cells, NK cells, T cell subsets) and serum immunoglobulin levels.
- Monitoring event-free survival and causes of mortality.
Main Results:
- One-year event-free survival was 67%, with infectious complications being the primary cause of death in three out of four fatalities.
- Prompt recovery of B cells (CD19+) was observed by 9 months post-transplant, with B cells being the predominant lymphocyte subset.
- Delayed recovery of CD3+CD8+ T cells was noted, with 7/8 patients having <100 cells/microl at 6 months, while CD3+CD4+ T cell recovery was less impaired.
Conclusions:
- U-CBT offers a viable treatment option for children with a 67% event-free survival in this cohort.
- Immune reconstitution is characterized by rapid B cell recovery and delayed T cell recovery, particularly CD8+ T cells, within the first year.
- Close monitoring of immune status is crucial for managing potential complications and improving long-term outcomes after U-CBT.
Abstract:
We report the outcome of 12 children who underwent unrelated cord blood transplant (U-CBT) in a single institution between February 1997 and July 1998. The 1 year event-free survival was 67% (95% CI of 26%). Four children died with infectious complication as cause of death in three cases. Immune reconstitution was studied during first year post transplant by assaying total lymphocyte counts, B cells, NK cells and T cell subsets in the eight disease-free surviving patients. We observed a prompt recovery of CD19+ cell number which was greater than 500/microl at 9 months for all patients except the one with severe cGVHD. B cells constituted the predominant lymphocyte subset at 6 and 9 months post transplant with normal or elevated B cell numbers according to normal paediatric range. We noted normal serum immunoglobulin levels at 6 months post transplant for IgA and IgM and at 9 months for IgG. The CD3+ cell count and particularly the CD3+CD8+ T cell subset remained depressed until 12 months post transplant. Six months after unrelated CBT, seven out of eight patients had less than 100 CD3+CD8+ cells/microl. CD3+CD4+ cell recovery was less impaired with all children achieving an absolute count of CD3+CD4+ cells greater than 200/microl during the first year in a median of 5 months. The percentage of NK cells was elevated during the first 6 months after CBT but their absolute count remained within the normal range. Bone Marrow Transplantation (2000) 25, 53-57.