Study: Virus may play role in Alzheimer’s

It has long been a controversial theory about Alzheimer’s disease, often dismissed by experts.

But a new study by a team that includes prominent Alzheimer’s scientists who were previously skeptics of this theory may well change that. The research offers compelling evidence for the idea that viruses might be involved in Alzheimer’s, particularly two types of herpes that infect most people as infants and then lie dormant for years.

The study, published Thursday in the journal Neuron, found that viruses interact with genes linked to Alzheimer’s and may play a role in how Alzheimer’s develops and progresses.

The authors emphasized that they did not find that the viruses cause Alzheimer’s. But their research, along with another soon-to-be-published study, suggests that viruses could kick-start an immune response that might increase the accumulation of amyloid, a protein in human brains that clumps into the telltale plaques of Alzheimer’s.

“These viruses are probably significant players in driving the immune system in Alzheimer’s,” said Joel Dudley, the study’s senior author and an associate professor of genetics and genomic sciences at the Icahn School of Medicine at Mount Sinai in New York. “I think they’re like gas on the flames of some pathology that may be immune-driven.”

The virus theory is far from being accepted by most Alzheimer’s experts.

The researchers searched in about 2,000 samples from 944 brains of people who had died — some with Alzheimer’s, some with other types of neurological problems, and some without cognitive impairment. The idea was to see if any viral gene sequences were more abundant in Alzheimer’s brains.