Harnessing the immune system to battle Alzheimer's

20th Century medicine can claim many victories against various maladies. Deadly diseases that plagued our ancestors only 100 years ago have become virtually unknown in the developed world. Smallpox has been eradicated and the World Health Organization is now striving towards the elimination of polio. Cases of mumps, rubella and measles are rare, while in an average winter, flu seems to be largely under control. And most of these outstanding and lasting achievements have been due to the use of effective vaccines.At the same time, however, these advances have led to a burgeoning ageing population in developed countries, and other diseases, for which there are as yet no cures, are becoming more prevalent. Along with cancer, heart disease and diabetes, Alzheimer's disease has now become a major threat to the growing ageing population. In the USA, 4.5 million Americans are living with this debilitating and ultimately deadly disease, and that number is expected to grow to 14 million by the middle of the century, according to the Alzheimer's Association in Chicago, IL. In the EU member states, ∼5% of people over 65 years suffer from the disease. As the risk of acquiring Alzheimer's grows with age—by age 65, one in 10 will have the disease, rising to five in 10 by age 85—it places a heavy burden on the social and medical infrastructure in our increasingly ageing societies. The annual cost of treating Alzheimer's disease in the USA is estimated to be ∼$100 billion—third only after heart disease and cancer, according to the philanthropic Institute for the Study of Aging in New York, NY.While Alzheimer's disease has been studied extensively for many years, only four drugs are currently approved for treatment—all of which are acetylcholinesterase inhibitors with only limited efficacy. And although scores of other drugs are in …