IMPEDED NORMAL HEMATOPOIESIS IN BONE-MARROW OF PATIENTS WITH MULTIPLE-MYELOMA

Insufficient output of mature blood cells frequently accompanies the t ypical impairments of late B cell development in multiple myeloma (MM) . In a large group of previously untreated patients, bone marrow sampl es were analyzed and showed a general decrease of mononuclear cell (MN C) content. Colony growth of granulo-monocytic progenitors in short-te rm assays is compromised in a substantial number of patients at partly severe degrees, who at the same time show higher plasma cell content and belong to clinically more severe groups; the other patients show n ormal in vitro growth, contain less plasmocytes in the marrow and belo ng to varying degrees of aggressiveness. Thus a heterogeneity of the d isease is emerging on the level of bone marrow cells which matches wit h high aggressiveness of the disease in one type. It can be speculated that in this type there are different underlying mutational events co mpared to the others: besides the characteristic changes in B cell dif ferentiation, here the cellular defects have an impact on normal granu lo-monocytic (and other) progenitor recruitment, which is absent in th e other cases.