DETECTION OF RESIDUAL DISEASE IN PATIENTS POST UMBILICAL CORD BLOOD TRANSPLANT

TSANG KS, LI CK*, SHING MMK*, WONG APY, YAU KH, LAU TT, CHIK KW*, LI K*, YUEN PMP*.

Departments of Anatomical & Cellular Pathology and *Paediatrics, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, Hong Kong

The finding of relative abundance of haematopoietic stem cells in umbilical cord blood (UCB) and the first successful UCB transplant in 1988 have inspired clinicians and scientists to cryopreserve UCB for the haematopoietic reconstitution of patients suffering blood malignancies or hereditary diseases after myeloablative therapy. Since October 1994 we have harvested 19 family-related, HLA-DR-matched UCB. In the past 2 years, a total of 4 UCB transplants were performed on HLA-identical siblings with allografts cryopreserved for 366 215 days (159-670) and the cell viability of 91.3 12.3% (71.2-99.9).

UPN/
Disease

Sex/
Age

Dnr
Sex

BW
(Kg)

Allograft/
ABO/Vol

NC/MNC
(x107/Kg)

CFU
(x104/Kg)

CD34+
(x105/Kg)

DOE
ANC/Plt

UCB1LLL
β-Thal Major

 
F/9

 
M

 
28.2

UCB
B+ → O+
88

 
2.95 / 0.46

 
0.85

 
0.29

 
NG

UCB7LCF
β-Thal Major

 
M/5

 
F

 
15.4

UCB+BM
B+ → B+
38 + 205

 
30.0 / 16.3

 
15.8

 
41.8

 
25 / 34

UCB11CYM
β-Thal Major

 
M/6.5

 
F

 
17.5

UCB+NB
B+ → B+
44 + 83

 
7.63 / 1.65

 
4.30

 
1.02

 
32 / 34

UCB12NKF
Monosomy 7

 
M/2.5

 
F

 
14.9

UCB
A+ → O+
102

 
5.81 / 2.56

 
4.37

 
1.15

 
32 / 39

DOE: day of engraftment, ANC: absolute neutrophils count, NG: non-grafted, NB: neonatal blood

Fluorescent in-situ hybridization (FISH) with probes against the sex- and/or 7-chromosome were performed on interphase cells of pre- and post-transplant marrow and blood samples. Polymerase chain reactions for the Y gene sequence were done on DNA extracted from the peripheral blood. Haemoglobinopathy investigations by both agarose electrophoresis and alkaline denaturation test were done on post-transplant blood samples to monitor the γ-globin gene expression. Cytogenetic analysis was also performed.

Non-engraftment occurred in UCB1LLL. FISH with Y probe showed that only 2.3% of the donor cells was present on day 34 despite the rebound of ANC to 0.5 x l09/L. Mixed chimerism was detected in the other 3 patients. The β-Thal patients were clinically stable and transfusion independent. Cytogenetic study showed constitutional XYY/XY mosaicism in UCB11CYM. Y-gene sequence was continuously detected on the post-transplant blood samples on day 145. The increased expression of foetal haemoglobin to 25.8% was seen. In UCB12NKF, FISH with probe for chromosome 7 showed a gradual increase of recipient cells to 9.2% on day 136, which antedated the clinical relapse. Three donor lymphocyte infusions were made on day 144, 219 and 255. Peak percentage of residual cells fell from 19% on day 249 to 3.7% on day 310. Graft versus leukaemia effect was seen with conspicuous clinical progression.


Copyright 1997 Hong Kong Medical Technology Association .
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