CD38 and plasma cell myeloma: Based on the favorable co-expression of CD38 and SLAMF7 antigen at high levels on MM, we tested hemibodies in vivo using myeloma xenografts and human peripheral blood mononuclear cells (PBMCs) in a humanized immunodeficient NOD SCID Il2rg−/− (NSG) mouse model (Fig. 3d).