Keratinocyte chemoattractant (KC), also called CXCL1, belongs to the family of alpha (CXC) chemokines and is suggested to be the homolog of human Gro-α. Gro-α/KC is an important chemoattractant and activating factor for neutrophils. Besides its recognized role in inflammation and angiogenesis, it shows antimicrobial effects. KC is expressed in mouse fibroblasts, macrophages, and endothelial cells and CXCR2 has been identified as its functional receptor. It has been shown that KC plays a critical role in the development of experimental Lyme arthritis and carditis in mice (Ritzman et al).