HLA-DR3 and DQA1*0401: possible risk factors in Alzheimer's disease

It has been suggested that an immune response may contribute to the pathoge nesis of Alzheimer's disease (AD), and therefore several studies have exami ned the possible association of AD with the Major Histocompatibility Comple x (HLA). In order to investigate whether there is susceptibility to AD invo lving the HLA class II antigens, we studied 97 AD patients and 53 controls. Our study included the HLA-dass II subgroups DRB1, DQA1 and DQB1. We also investigated whether there is a significant association be tween different HLA-class II alleles and the apolipoprotein E epsilon 4 allele (apoE epsilo n 4), an established genetic risk factor for AD. Univariate analysis establ ished an association between the apoE epsilon 4 allele and AD, as expected. When HLA-DRB1, DQA1 and DQB1 were analysed as independent genes, we found an association between the presence of DQA1*0401 and AD. However this may b e because of the small numbers in our AD population and the total absence o f the allele in our control population. Using logistic regression analysis including apoE genotype, HLA-DRB1, DQB1 and DQA1 alleles as potential predi ctors of the presence of AD, only apoE epsilon 4 status and the absence of the DR3 allele showed a significant association with AD. This further weake ns the possible association of AD and DQA1*0401. There was no association w ith either HLA-DR3 or DQA1*0401 and the apoE genotype.