Roanoke Times
Copyright (c) 1995, Landmark Communications, Inc.
DATE: THURSDAY, September 22, 1994 TAG: 9409260001
SECTION: NATIONAL/INTERNATIONAL PAGE: A-6 EDITION: METRO
SOURCE: Associated Press
DATELINE: NEW YORK LENGTH: Medium
If that is correct and the virus can be identified, scientists may be able to devise a vaccine against type I diabetes, said the study's chief author, Dr. Massimo Trucco of the University of Pittsburgh.
Scientists know that type I diabetes, also called juvenile diabetes, occurs when the disease-fighting immune system destroys insulin-producing cells in the pancreas. But the cause of that attack is unclear.
The new work suggests that the immune system is attracted by a protein on the pancreas cells' surfaces that comes from a virus infection in the cells.
Viruses have been suggested as a cause of the immune system attack before, but researchers have been moving away from that idea, said Kenneth Farber, executive director of the Juvenile Diabetes Foundation International.
Trucco's study is ``a provocative finding that needs to be followed up,'' Farber said. ``It will be. You can count on it.''
Type I diabetes usually appears in childhood or adolescence. It is more severe than the other main form of diabetes, type II, which usually appears after age 30 and often can be controlled through dieting and exercise.
Genes play a role in type I diabetes, and Trucco said the virus would cause trouble only in people whose genes make them vulnerable to the disease.
Trucco's work is reported in Thursday'stoday's issue of the journal Nature. He and his colleagues examined immune system cells taken from the pancreases of two boys who died soon after type I diabetes was diagnosed.
An analysis of the immune system cells, called T cells, showed that they apparently attacked a ``superantigen,'' a protein that activates an unusually wide variety of T cells. Superantigens come from viruses and bacteria, but a virus appears more likely in this case, Trucco said.
Another piece of evidence has emerged more recently. Trucco said pancreas cells of both patients were found to have high levels of a protein called reverse transcriptase, which is found only in a class of virus called a retrovirus.
The best-known member of this class is the AIDS virus, but Trucco said the finding does not imply that diabetes has anything to do with AIDS.
Retroviruses reproduce themselves within cells and, during that process, the cell displays proteins from the virus on its surface, Trucco said. Those proteins can draw the immune system's attack, he said.
If the virus triggers diabetes, scientists might be able to devise a vaccine to give to newborns, whose immune systems are still organizing themselves. The vaccine might make the immune systems eliminate T cells that would otherwise attack the insulin cells later, Trucco said.
KEY FINDINGS
A study of immune system cells from two diabetes patients suggests that the most severe form of the disease may be triggered by a virus.
If that is so and the virus can be identified, researchers may be able to devise a vaccine against the disease.
by CNB