CD68/SR-D1. CD68, also called Scavenger Receptor D1(SR-D1) and LAMP-4, is a heavily glycosylated type I transmembrane glycoproteinthat belongs to the LAMP family (1). Human CD68 contains 354 amino acids (aa), witha 21 aa signal sequence and a 298 aa extracellular domain (ECD), a 25 aatransmembrane domain, and a 10 aa cytoplasmic domain. The ECD of CD68 has 9 glycosylation sites and a mucin-like region in aa 23-140. Within the ECD, humanCD68 shares a 65% and 67% amino acid sequence identity with that of mouse andrat CD68, respectively. CD68 is expressed onmonocytes and tissue macrophages and serves as a scavenger receptor foroxidized LDL (2).  In contrast to other members of the LAMP-family ofglycoproteins which are ubiquitously expressed in all cell types, CD68 appearedto have a more restricted, cell-type specific pattern of expression (3 ,4). CD68 is alsoa biomarker of rheumatoid arthritis and Hodgkin's lymphoma (5, 6). CD68influences the functions of cells through NF-kB/focal adhesion kinase pathway (7).In addition, CD68 on macrophages binds tightly to both S100A8 and S100A9 toenhance the cell immunity (8).