Mobilisation of tumour cells along with CD34+ cells to peripheral blood in multiple myeloma.
BACKGROUND
Cells belonging to the malignant clone are found in the peripheral blood in myeloma patients. In order to minimise the content of tumour cells in the stem cell product it is crucial to perform stem cell harvest at a time when tumour cells in the peripheral blood are at a minimum.


OBJECTIVE
The aim of the study was to compare the mobilisation kinetics of normal CD34+ cells and myeloma plasma cells during mobilisation with either G-CSF alone or high-dose cyclophosphamide (HDCy) plus G-CSF.


METHODS
Morning blood samples were drawn each day during mobilisation from start of G-CSF or HDCy and to the end of leukapheresis, and were analysed by flow cytometry for content of CD34+ cells and myeloma plasma cells (CD38+ + CD45-). Tumour cells were also estimated by a patient-specific real-time polymerase chain reaction (PCR) method based on the 5' nuclease TaqMan technology.


RESULTS
Flow cytometry data from 16 patients showed concomitant mobilisation of CD34+ cells and myeloma plasma cells. Seven patients were mobilised twice; first with G-CSF alone and then with HDCy plus G-CSF. There was no difference between the two mobilisation regimens regarding tumour cell mobilisation kinetics. Real-time PCR was performed in one patient and confirmed the mobilisation of tumour cells at the time when CD34+ blood cells were at a maximum.


CONCLUSIONS
Tumour cells are mobilised to the peripheral blood at the same time as CD34+ cells in multiple myeloma patients after priming with both G-CSF alone and HDCy in combination with G-CSF.
Knudsen
L M
LM
Department of Haematology L, Herlev Hospital, University of Copenhagen, Herlev, Denmark. l.meldgaard@dadlnet.dk
Rasmussen
T
T
Nikolaisen
K
K
Johnsen
H E
HE
D000328:Adult; D018952:Antigens, CD34; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology; D002452:Cell Count; D002469:Cell Separation; D003520:Cyclophosphamide / Q000494:pharmacology; D005260:Female; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood / Q000473:pathology* / Q000628:therapy; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014182:Transplantation, Autologous
D018952:Antigens, CD34; D018906:Antineoplastic Agents, Alkylating; D016179:Granulocyte Colony-Stimulating Factor; D003520:Cyclophosphamide