Monocyte chemoattractant protein-1 (MCP-1) gene polymorphism and risk of Alzheimer's disease in Italians

Monocyte chemoattractant protein-1 (MCP-1) is a key molecule for monocyte chemotaxis and tissue extravasation and for the modulation of leukocyte function during inflammation. Upregulation of MCP-1 may occur in the brain of subjects affected by Alzheimer's disease (AD) and MCP-1 levels in plasma and cerebrospinal fluid have been proposed as biological markers for the inflammatory process that accompanies AD pathogenesis. Importantly, serum levels and biological activity of MCP-1 protein are strongly influenced by a single nucleotide polymorphism occurring at position -2518 of the MCP-1 gene promoter. A recent study has investigated the possible association between this gene polymorphism and AD in a Spanish population, with negative results. Here, we performed a case-control study to test whether the risk for AD might be influenced by the -2518 A/G polymorphism of the MCP-1 gene in an ethnically homogeneous Italian population. The GG genotype and the G allele of the MCP-1 gene polymorphism were significantly more common in the AD group than in control individuals (P<0.0001) A logistic regression analysis indicated that the GG genotype was an independent risk factor for AD in our population. This effect was not influenced by the presence of the APOE 4 high-risk allele, nor by the presence of other gene variations associated with a pro-inflammatory phenotype. These findings indicate that the -2518 A/G polymorphism of the MCP-1 gene is associated with AD in Italians and confirm that inflammatory gene variations may be important contributors in the development and progression of neurodegenerative disorders.