Time to abandon dogma: CD14 is expressed by non-myeloid lineage cells.

CD14 is a pattern recognition receptor; its important role in innate immunity is reviewed here. Since its discovery and subsequent classification at the first leucocyte typing workshop in 1982, CD14 has been thought of as a leucocyte differentiation antigen. However, it has become clear that CD14 is also expressed by many non-myeloid cells, and the evidence for this is presented. The possible role of the presence of low copy number CD14 on non-myeloid cells is discussed. It is time to acknowledge CD14 as an ubiquitous molecule and abandon the position that it is expressed by myeloid cells alone.