The CX3CL1–CX3CR1 system and psoriasis

CX3CL1 is a chemoattractant and adhesion molecule that induces the redistribution of CX3CR1-positive inflammatory leucocytes to sites of inflammation. As a consequence of their increased expression in plaques of psoriasis, and location within genomic regions previously linked to this disease, CX3CL1, and its receptor CX3CR1, represent attractive positional and functional 'psoriasis susceptibility genes'. To investigate the CX3CL1-CX3CR1 system in psoriasis, eight single nucleotide polymorphisms (SNPs) in CX3CL1 and two SNPs in CX3CR1 were genotyped in 281 psoriasis patients and 184 unrelated controls. Allele, genotype and estimated haplotype frequencies were then compared between experimental groups. Allele frequency differences between healthy volunteers and psoriasis patients revealed associations with two CX3CR1 SNPs (hCV11578468, P = 0.03 and c_5687_1, P = 0.04). No associations were observed between CX3CL1 SNPs and psoriasis. These results support a role for the CX3CL1-CX3CR1 system in the pathogenesis of psoriasis and identify SNPs within the chemokine receptors that are associated with the disease.