Abstract
Bone marrow aspirates form patients with multiple myeloma were obtained and lymphocytes were isolated using density gradient centrifugation. The APase activity of the samples ranged from 12 to 88 nmol/0.2 × 10(6) cells as compared to the very low activity present in normal human peripheral blood lymphocytes PBL. Neither the unstimulated nor the mitogen stimulated lymphocytes from peripheral blood of normal humans showed appreciable APase activity. The lymphocytes from bone marrow of multiple myeloma patients as well as myeloma cell lines-RPMI 8226 and U266 B1 express APase activity constitutively. The results of the present investigation are discussed in the light of existing literature.