Abstract
Objective
The immune system (IS) plays a key role in the mechanisms underlying major depression (MD) and pro‐inflammatory cytokines seem to be particularly involved in the pathogenesis of the disease. There is growing evidence of a relationship between commonly studied single nucleotide polymorphisms (SNPs) in cytokine genes and an increased risk of MD.
The aim of our study was to investigate the association between the −308(G/A) SNP in the tumour necrosis factor‐α (TNF‐α) gene and late‐life MD in elderly people without dementia.
Methods
Blood samples were obtained from 50 subjects enrolled at the Geriatric Department of the San Gerardo Hospital in Monza, Italy, after screening with the geriatric depression scale (GDS ≥ 15) and mini‐mental state evaluation (MMSE ≥ 24). The −308 (G/A) SNP was genotyped by SSP‐PCR amplification. Two hundred and forty age‐matched healthy volunteers were taken as the control group.
Results
Genotype and allele distributions in patients with MD were significantly different from those of the controls. In subjects affected by MD we found a higher percentage of the GG genotype (84 vs. 68,3%; p = 0.007) and thus of the G allele (92 vs. 81,9%; p = 0.05).
The GG genotype was associated with a greater risk of developing the disease (OR 2.433, CI 1.09–5.43).
Conclusions
Our study suggests that the −308 (G/A) polymorphism in the TNF‐α gene could play a role in determining susceptibility to MD. An activation of the TNF‐α system could contribute to the development of MD in the elderly. Copyright © 2009 John Wiley & Sons, Ltd.