Immunoglobulins contain, amongst other things, anti-bodies against a protein which is thought to trigger off Alzheimer's. In a pilot study carried out on five Alzheimer's patients the team gave the patients an immunoglobulin injection intravenously every four weeks throughout the six-month study.
Before beginning and on completing the therapy the researchers determined the beta-amyloid content in the blood and the CSF fluid, the liquid which is present in the brain and spinal cord.
Dr. Richard Dodel, lead researcher of the study said: "On average the beta-amyloid concentration in the fluid decreased in the course of the study by over 30 per cent, while the concentration in the blood rose 2.3 times."
"The immunoglobulins therefore seem to have the effect of flushing out the beta-amyloid from the brain. How exactly this occurs is as yet unclear."
However, the medical team involved emphasise its findings are still very tentative. They are now planning a large-scale double-blind clinical trial with about sixty patients so as to further confirm the positive effect of the immunoglobulins.
The cerebral cortex of Alzheimer's patients regularly contains large protein aggregates, what are known as Alzheimer's glands. They predominantly consist of beta-amyloid peptide, a small protein. This peptide collects in the brain of Alzheimer's patients and forms protein deposits which can damage and even destroy the sensitive nerve cells.
This latest approach appears to confirm animal experiments in which injections of beta-amyloid anti-bodies led to a reduction in the protein deposits and an improvement in the behavioural deficits in these animals.
Another study recently showed that immunising was not only able to reduce amyloid plaques, it also prevented the formation of the abnormal tau protein.
The team led by the Bonn lecturer Dr. Richard Dodel was able to show that every person's blood contains anti-bodies against beta-amyloid, but that the concentration in Alzheimer's patients is markedly lower.
"There are already antibody blood preparations which are used for particular diseases of the nervous system such as multiple sclerosis, which are known as immunoglobulins," Dodel explained.
The results are set out in the forthcoming edition of the Journal of Neurology, Neurosurgery and Psychiatry (vol. 75, pp. 1472-1474), which also devotes its editorial to this discovery.
There are an estimated 18 million people in the world with dementia, accordng to the charity Alzheimer's Disease International, which estimates that by 2025 this figure could increase to 34 million. And finding a treatment that could delay onset by just five years could reduce the number of individuals with Alzheimer's disease by nearly 50 per cent after 50 years.