Detection of malignant B cells in peripheral blood stem cell collections after chemotherapy in patients with multiple myeloma
Dreyfus, F.; Ribrag, V.; Leblond, V.; Ravaud, P.; Melle, J.; Quarre, M.C.; Pillier, C.; Boccaccio, C.; Varet, B.
Bone Marrow Transplantation 15(5): 707-711
1995
ISSN/ISBN: 0268-3369 PMID: 7670399 Document Number: 451615
Autologous transplantation after high-dose chemo or radiotherapy is now frequently used for the treatment of patients with multiple myeloma (MM). The collection of peripheral blood stem cells (PBSC) has a theoretical advantage over autologous bone marrow collection as the malignant plasmacytic contamination is believed to be lower. However, the extent of B cell contamination in PBSC has not been extensively investigated. Using an immunoglobulin heavy chain gene 'fingerprinting' technique at diagnosis and during apheresis after one cycle of chemotherapy we detected a monoclonal population in 44% of PBSC samples (9 positives in 22 studied). There was no correlation between contamination and sex, age, Durie and Salmon classification, C-reactive protein and albumin. A significant correlation was observed with beta-2 microglobulin serum level (P = 0.02). Twenty one patients were grafted and up to the present, with a mean follow-up of 12 months, 6 patients have relapsed including 4 patients with contaminating B cells. Our results suggest that PBSC contamination, defines a 'poor risk' group of patients, with poor prognosis. However, we could not exclude reinitiation of the disease by plasmacyte stem cells after grafting.