UNLABELLED: Multiple myeloma plasma cells are actively dividing cells with the long surviving ability in the ex-vivo culture. In the effort for better understanding of the proliferative potential of malignant myeloma cells and establishment of permanent myeloma cell lines we performed long term cultures of human myeloma cells ex-vivo. During the last two years we cultured 41 bone marrow samples from 39 patients with multiple myeloma. Cells were cultured in the RPMI 1640 culture medium with 15% fetal calf serum at 37 degrees C in 5% CO2 and approximately one third of the culture medium was changed regularly twice a week. Most of the marrows cultures died by apoptosis within 30 days. Four bone marrow samples were cultured for more than 11 months, however, no culture can be qualified as an established cell line. In three cases permanent B-lymphoblastoid cell lines were established (UHKT-55, UHKT-56 a UHKT-57) but secondary immortalization by Epstein-Barr virus was suggested. CONCLUSIONS: Presented results suggest that myeloma plasma cells can survive and are able to proliferate in the ex-vivo culture for several months up to one year independently on the addition of any external growth factor without spontaneous apoptosis or necrosis. The probability of the establishment of a permanent cell line of plasma cell origin is, however, low. Presence of accessory bone marrow cells was the most important factor for the long-term survival of myeloma cells.

Ustav hematologie a krevní transfuze U nemocnice 1 128 20 Praha 2 Czech Republic