Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

Chronic lymphocytic leukaemia (CLL) is a disease characterized by abnormal accumulation of B cells in the blood, bone marrow, lymph nodes and spleen. Several decades ago, it was concluded that CLL lymphocytes might be unable to proliferate in vivo but a recent study performed in vivo in patients with CLL has shown in contrast that these cells proliferate. However, an important and still unanswered question is whether CLL cells proliferate faster or slower compared to their normal counterparts. In this context, the turnover of CLL cell population was compared to the kinetics parameters of normal B lymphocytes after labelling with deuterium glucose. We have also compared the metabolic activity of CLL cells with B lymphocytes from healthy subjects using a new method for measuring RNA turnover in vivo. Based on these observations, we found that leukaemic cells proliferate less frequently than healthy patient and that metabolic activity via measurement of RNA turnover rate is significantly reduced in CLL patients.