Th e protein was fi rst identifi ed as a diff erentiation marker on the surface of monocytes and macrophages and was designated CD14 at the fi rst leukocyte typing workshop in Paris in 1982. Th e genomic DNA of human CD14 was cloned in 1988 and the gene was later mapped to chromo some 5q23-31. Several polymorphisms have been found in the CD14 gene, of which nucleotide polymorphisms at position -159 and -1619 correlated with decreased lung function in endotoxin-exposed farmers [3] .