The CD19+ B-cell counts at peripheral blood stem cell mobilization determine different levels of tumour contamination and autograft purgability in low-grade lymphoma.
The tumour load of peripheral blood stem cell (PBSC) harvests and the outcome of ex vivo immunomagnetic B-cell purging was investigated in 19 patients with low-grade lymphoma. To quantify the tumour load, we combined fluorescence-activated cell sorting measurement of CD19+ B-cells and determination of the B-cell light chain ratio (LCR) with consensus complementarity-determining region III-polymerase chain reaction (CDRIII-PCR) and gene scan analysis. The number of tumour cells was calculated using B-cell extracts from the PBSCs. Two different patterns were distinguished. In eight patients (42%) with CD19+ B cells >1% in the apheresis product, a high tumour load was found, characterized by a monoclonal LCR, positive PCR in seven out of eight cases, >5 x 10(7) extracted lymphoma cells in six out of seven PCR-assessable cases, and the presence of residual lymphoma after purging in six of seven cases. In 11 patients (58%) with <1% CD19+ B-cells in the product, a low tumour load was indicated by a polyclonal LCR, positive PCR in only 4 out of 11 cases, >5 x 10(7) extracted lymphoma cells in zero out of four PCR-assessable cases, and the presence of residual lymphoma after purging in zero out of four of these cases. The level of residual lymphoma following purging largely depended on the level of tumour contamination. CD19+ B-cells >50/microl in the peripheral blood at mobilization predicted a high tumour load in the apheresis product.
Straka
Christian
C
Medizinische Klinik-Innenstadt, University of Munich, Munich, Germany. cstraka@medinn.med.uni-muenchen.de
Oduncu
Fuat
F
Drexler
Eva
E
Mitterer
Manfred
M
Schnabel
Brigitte
B
König
August
A
Brack
Norbert
N
Nerl
Christoph
C
Emmerich
Bertold
B
D000328:Adult; D018941:Antigens, CD19 / Q000032:analysis; D016175:B-Lymphocyte Subsets / Q000473:pathology*; D016465:Bone Marrow Purging / Q000379:methods; D005260:Female; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D018189:Immunomagnetic Separation / Q000379:methods; D018655:Lymphocyte Count; D008228:Lymphoma, Non-Hodgkin / Q000473:pathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D009360:Neoplastic Cells, Circulating / Q000473:pathology*; D014182:Transplantation, Autologous
D018941:Antigens, CD19