CD300C also known as CLM-6 (CMRF35-like molecule 6), is a 224 amino acid single-pass type I membrane protein that is present on the surface of neutrophils, monocytes and a select proportion of peripheral blood B and T lymphocytes. CD300C contains two potential N-gylcosylation sites, a potential O-glycosylated hinge-like region and an Ig-like V-type (immunoglobulin-like) domain that is very similar to the Fc receptor for polymeric IgA and IgM. The gene encoding CD300C is localized to a region on human chromosome 17 that harbors a susceptilibty locus for psoriasis, dermatitis and rheumatoid arthritis, suggesting a possible involvement of CD300C with these conditions.