Sibling HLA-matched cord blood transplant for beta-thalassemia: report of two cases, expression of fetal hemoglobin, and review of the literature.
OBJECTIVE
A program of cord blood stem cell (CBSC) transplants for patients with beta-thalassemia major was initiated in conjunction with the prenatal diagnostic service in 1994. Two patients who received HLA-matched related CBSC transplants with posttransplant fetal hemoglobin (HbF) expression are described and the literature is reviewed.


METHODS
After screening 12 pregnancies, matched sibling CBSC transplants were performed for 2 girls with beta-thalassemia major when they were 3.8 and 2.2 years old, respectively. Their HbF was assayed serially.


RESULTS
The nucleated cell counts/kg were 11.4 x 10(7) and 6.2 x 10(7), which engrafted on days 19 and 24, respectively. The children are now transfusion-independent at 3 years and 1.2 years posttransplant. Their HbF levels showed a rapid rise posttransplant and reached peak levels of 37.2% and 42.2% on day 83 and day 88, respectively. The HbF levels declined to 1.0% and 3.8% on day 581 and day 305, respectively. Nine other sibling CBSC transplants for thalassemias have been reported with an engraftment rate of approximately 50%. Graft rejection was related to insufficient CBSC number in one.


CONCLUSIONS
HbF levels in patients with beta-thalassemia major after CBSC transplants could be influenced by many factors, including reactivation of HbF synthesis, intrinsic rate of Hb switching of CBSC, and mixed chimerism.
Lau
Y L
YL
Department of Pediatrics, University of Hong Kong, Queen Mary Hospital, China.
Ma
E S
ES
Ha
S Y
SY
Chan
G C
GC
Chiu
D
D
Tang
M
M
Hawkins
B R
BR
Chan
V
V
Liang
R H
RH
D005260:Female; D005312:Fetal Blood; D005319:Fetal Hemoglobin / Q000096:biosynthesis*; D016332:Fetal Tissue Transplantation; D006085:Graft Survival; D018380:Hematopoietic Stem Cell Transplantation; D006650:Histocompatibility Testing; D006801:Humans; D007223:Infant; D014184:Transplantation, Homologous; D017086:beta-Thalassemia / Q000097:blood / Q000276:immunology / Q000628:therapy*
D005319:Fetal Hemoglobin