Study the biomarkers recorded on plasma cells and normal leukocytes including T lymphocytes (naïve, effectors and memories), B lymphocytes, Treg, NK, monocytes as well as their activation markers (CD25, PD-1) in paired bone marrow and blood samples. Validate the pre-analytical stability of the samples between T0 (< 4 hours after sampling) and T0 + 72 hours.~Secondary objectives: Validate the strategy of quantification of receptors on plasma cells by direct labeling in flow cytometry. Validate a new method for measuring receptor occupancy by a drug. Validate the pre-analytical stability of the absolute quantitative expression of the receptors and the specific marker CD138 on samples between T0 (< 4 hours after sampling) and T0 + 72 hours.~The study will be enrolling 20 patients.
The objective of this study is to evaluate the immune profile of plasma cells and immune effector cells in paired peripheral whole blood and bone marrow samples from MM patients by standardized flow cytometry. The quantitative and/or qualitative variation of these immune effectors according to the different status of myeloma pathology (diagnosis, relapse or refractory). It is interesting to assess the extent to which a particular immune profile is associated with a better therapeutic response for a given treatment.~In addition, the study will validate the stability of the samples between T0 (< 4 hours after sampling) and T0 + 72 hours.