A polymorphism of the interleukin-1 beta gene at position +3953 influences progression and neuro-pathological hallmarks of Alzheimer’s disease

Interleukin-1 (IL-1) gene polymorphisms are associated with an increased risk of Alzheimer’s disease (AD) and it has been suggested that altered immune responses of the brain may play a role in the pathogenesis of the disease. Here we investigated whether IL-1β polymorphisms affected neuro-pathological features and clinical status of AD patients with autopsy confirmed diagnosis of the disease. AD patients (n=133) were genotyped for the polymorphic regions in the apolipoprotein E var epsilon (APOE var epsilon) and interleukin-1β (IL-1β)) genes. APOE var epsilon4 carriers showed increased neuritic amyloid plaques (NP) and neurofibrillary tangles (NFT). The IL-1β +3953 polymorphism influenced survival in AD patients and those with the TT genotype and without the APOE var epsilon4 allele showed the shortest cumulative survival. Patients with the +3953 IL-1β T and without the APOE var epsilon4 alleles had reduced NP and NFT, a delayed ages at onset and death, but a decreased duration of the disease. On the other hand a different polymorphism of the IL-1β gene at position −511 did not influence any AD features. Our findings suggest that IL-1β gene by affecting brain immune responses may influence the age at onset of the disease, survival and AD progression.