MICB and AL amyloidosis: In a different scenario, LXRs activation could upregulate MHC class I polypeptide-related sequence-A (MICA) and MICB expression in multiple myeloma cells, two ligands of the NK cell-activating receptor NK group 2 member D (NKG2D), by enhancing MICA promoter activity and inhibiting MICB degradation in lysosomes, thus improving NK cell-cytotoxicity (46).