CD1D and plasma cell myeloma: In myeloma patients, lysophosphatidylcholine (LPC)-loaded CD1d dimers stained on average 0.6% of T cells in PBMC, several fold higher than type I NKT cell numbers determined with α-GalCer-loaded CD1d dimers (68), whereas in healthy controls, both LPC- and α-GalCer-loaded CD1d dimers stained approximately 0.05% of PBMC.