Alkaline Phosphatase Activity of Normal and Malignant Human Lymphocytes.

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 × 106 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.

Effect of levamisole on expression of CD138 and interleukin-6 in human multiple myeloma cell lines.

INTRODUCTION: Multiple myeloma (MM) is a B-cell malignancy accounting for 0.8% of all cancer deaths globally. This malignancy is characterized by lytic bone disease renal insufficiency, anemia, hypercalcemia, and immunodeficiency. The myeloma cells have enhanced expression of CD138. CD138 is a transmembrane heparin sulfate glycoprotein expressed on different types of adherent and nonadherent cells.CD138 is used as a standard marker for identification of tumor cells. AIMS AND OBJECTIVES: Despite introduction of many therapeutic agents, the management of multiple myeloma (MM) remains a challenge and search for new therapeutic agents is in progress. In this study, we attempted to evaluate the effect of an alkaline phosphatase inhibitor, levamisole on expression of CD138, and level of interleukin-6 (IL-6) in human MM cell lines RPMI 8226 and U266 B1. MATERIAL AND METHODS: U266B1 and RPMI 8226 cell lines were obtained from the National Centre for Cell Sciences, Pune. Alkaline phosphatase assay, Interleukin-6 assay and CD138 expression on myeloma cells by flow cytometry were investigated when the cells were exposed to Levamisole. RESULTS: Levamisole-mediated growth inhibition of myeloma cells in vitro is associated with a loss of CD138 and increased IL-6 secretion. The increased secretion of IL-6 by myeloma cells could be an attempt to protect themselves from apoptosis. CONCLUSION: Levamisole inhibited CD138 expression and affected the levels of IL-6 in a dose-dependent manner. The results of the present study add new dimension to levamisole's mode of action as inhibitor of CD138 and IL-6 and as an antiapoptotic agent.