Siglec-7, which is highly expressed in monocytes and resident blood cells but not in parenchymatous cells, mediates inhibition of natural killer cell cytotoxicity. Due to alternative splicing events, two isoforms exist for Siglec-12, namely SLG-L (the long isoform) and SLG-S (the shorter isoform). These isoforms are differentially expressed with the longer isoform predominantly found in small intestine, spleen and bone marrow, and the shorter isoform predominantly found in small intestine, spleen and adrenal gland.