Chemokine(C-C motif) ligand 18(CCL18) is a small cytokine belonging to the CC chemokine family that was previously called PARC(pulmonary and activation-regulated chemokine). CCL18 is approximately 60% identical in amino acid sequence to CCL3. By analysis of a previously mapped CCL18 from 17q11.2, it is determined that the PARC gene is located within 1 of the 2 clusters of CC chemokine genes in this region. It is expressed at high levels in lung and at lower levels in certain lymphoid tissues, such as the lymph nodes, and is chemotactic for activated T cells and nonactivated lymphocytes. Beside, CCL18 recruits Th2 cells and basophils and may play a predominant role in allergic asthma.
