NK Cell Recovery and Costimulatory Molecule Profiles After Autologous Hematopoietic Cell Transplantation (HCT) in Multiple Myeloma (MM) Patients

Background: MM patients with enhanced immune responses following AHSCT are known to have better long-term disease control. While it has been shown that early responses are mediated by NK cells and alternate inhibitory/stimulatory pathways, including costimulatory molecules, the characterization of these costimulatory molecule profiles in MM patients post AHSCT is not well established. To address this issue, we conducted a pilot study designed to characterize NK cells and function after AHSCT in MM patients through the expression of a cytolytic receptor (CD16), an antibody-dependent cell mediated cytotoxic (ADCC) receptor, and through NK cells functional status based on interferon gamma (IFN-γ) expression as well as the expression of stimulatory (4-1BB) and inhibitory (PD-1 and CTLA-4) molecules. The aims are to characterize the inhibitory and activating costimulatory pathways involved in immune reconstitution after autologous transplantation and to describe changes in the immune signature profile post transplant in response to maintenance therapy and disease status.