BLT1 is a Chemoattractant Receptor that binds the potent chemoattractant leukotriene B4 (LTB4) which is involved in defense against infection. Leukotriene B4 also activates the transcription factor PPAR alpha, resulting in the activation of genes that terminate inflammatory processes (Yokomizo et al., 1997). Although BLT1 shows homology to other P2Y receptors, it does not function as a purinoreceptor ( Yokomizo et al., 1997). Part of the coding regions of BLTR2 have been duplicated and are part of the 5' UTR noncoding regions of the clusters BLT1 and CIDE-B on chromosome 14.