Peripheral blood cells chimerism after unrelated cord blood transplantation in children: kinetics, predictive factors and impact on post-transplant outcome.
This study aimed to describe kinetics of complete donor chimerism occurrence (cDC, >99·9% donor) after unrelated cord blood transplantation (UCBT), to identify its predictive factors and its impact on post-transplant outcome. Ninety-four children who received single UCBT after a myeloablative conditioning regimen had blood chimerism evaluation at predefined post-transplant dates, using a real-time polymerase chain reaction method with 0·1% sensitivity. Cumulative incidence of cDC at 1 year post-transplantation was 61·8%. Three predictive factors were identified in multivariate analysis: history of malignant disease (P = 0·03), older age (above 2·16 years, the first quartile of age, P = 0·0055) and higher level of cord/recipient human leucocyte antigen mismatch (4/6 vs. 5-6/6, P < 0·001) increased the probability of post-transplant cDC. Although graft cell dose had a strong impact on haematological recovery, it did not apparently influence cDC occurrence. Early cDC (i.e. more than 99·9% donor chimerism on days 15-30 post-transplant) appeared useful to predict engraftment (P = 0·003) as well as acute and chronic graft-versus-host disease (GvHD). Severe acute or chronic GvHD never occurred in patients with DC ≤99·9%, suggesting than even minimal residual host haematopoiesis is associated with a very low risk of GvHD after UCBT.
Department of Paediatric Haematology-Oncology, APHM, La Timone Hospital, Aix-Marseille University, Marseille, France.
Elodie
E
Elkaim
Christophe
C
Picard
Claire
C
Galambrun
Vincent
V
Barlogis
Anderson
A
Loundou
Catherine
C
Curtillet
Claire
C
Oudin
Isabelle
I
Thuret
Hervé
H
Chambost
Gérard
G
Michel
D000293:Adolescent; D064591:Allografts / Q000502:physiology; D002648:Child; D002675:Child, Preschool; D036101:Cord Blood Stem Cell Transplantation / Q000009:adverse effects*; D005260:Female; D006086:Graft vs Host Disease / Q000209:etiology; D006410:Hematopoiesis / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D015778:Minor Histocompatibility Antigens; D011446:Prospective Studies; D018183:Transplantation Chimera / Q000502:physiology*; D019172:Transplantation Conditioning / Q000379:methods; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D015778:Minor Histocompatibility Antigens
childhood; chimerism; graft-versus-host disease; human leucocyte antigen compatibilty; unrelated cord blood transplantation