Description of the Immune Deficiency in Patients With Untreated Chronic Lymphocytic Leukemia and Search for Predictive Factors of Infectious Risk

Chronic Lymphocytic Leukemia (CLL) is the most common adult leukemia in western countries. CLL is most often discovered incidentally when a blood test carried out for another reason highlights an increase of subpopulation of white cells called lymphocytes. It is also sometimes diagnosed when complications such as an increase in the size of the lymph nodes or a decrease in other blood lines (red blood cells and platelets) occur. Its evolution is heterogeneous and only patients with symptoms require treated. CLL is aso characterized by its hability to induce immunodeficiency, which tends to worsen over time, even in patients who do not receive any treatment. Thus, patients with CLL have more infections than the general population, and these infectious complications are the leading cause of death. Similarly, vaccination, whether directed against classical pathogens such as influenzae or more recently against SARS-CoV2, is less effective in patients with CLL. The causes of this immune deficiency are not completely elucidated and the objective of our study is to analyze different subpopulations of lymphocytes thanks to a blood sample. The investigators thus hope to be able to determine more precisely the reasons underlying these infections in order to better prevent them.