autologous blood and marrow transplantation - Blog Science ...

Mapara et al. 535
A i m :
P u r g i n g b y a d e n o v i r u s m e d i a t e d g e n e t r a n s f e r o f s u i c i d e g e n e s i n t o
m i c r o m e t a s t a t i c b r e a s t c a n c e r c e l l s
Figure 1. Adenovirus-mediated purging.
other groups have demonstrated that such an approach does not compromise long-
term culture-initiating human hematopoietic stem cells. 25,26
DISCUSSION
Concerning combined positive and negative selection, different groups have
reported comparable results with regard to CD34 yield, purity, and purging
efficiency. Negrin and co-workers reported on a combined purging procedure in
patients with non-Hodgkin's lymphoma. As a first step, CD34 cells were enriched
using density gradient centrifugation and subsequently purged using antibodycomplement
lysis. 14
This procedure achieved a median CD34 recovery of 81.2%,
albeit with a broad range of 9.9 to 302.6%. Purging efficiency was monitored by
fluorescence-activated cell sorting (FACS) analysis and, in some cases of patients
with follicular lymphomas, using t(14;18) specific polymerase chain reaction (PCR).
They were able to show that combined purging was superior to CD34 enrichment
alone. They were able to achieve PCR negativity after combined purging in three of
three apheresis products and in two of three bone marrow harvests. However, it must
be considered that the defined density gradient for eliminating lymphoma cells might
not be applicable to other malignant diseases. Recently, Paulus et al. 27
used a method
similar to our procedure in B-CLL patients and were also able to improve purging
efficiency considerably, purging beyond the detection limit by flow cytometric
analysis. However, clonal B-cells were still detectable using a sensitive CDR-HI-
PCR. 27
Nevertheless, these results are in line with our observations that