To test whether the enhanced anti-myeloma activity of the combination of elotuzumab and lenalidomide was the result of increased immune cell infiltration into the xenografts, immunohistochemistry was performed on established OPM2 xenografts to identify the presence of NKp46+ NK cells and F4/80+ monocyte infiltrates from mice treated with cIgG1, elotuzumab, cIgG1 plus lenalidomide, or elotuzumab plus lenalidomide. This evidence concerns the gene NCR1 and plasma cell myeloma.