Can Immune Treatment Cure Diabetes?
Type 1 Diabetes Immune Dysfunction May Be Treatable
June 25, 2007 (Chicago) -- With increasing optimism, scientists report
progress in immune therapies that could stop type 1 diabetes in its tracks.
Type 1 diabetes is an autoimmune disease. This means that the body's
powerful immune responses -- designed for protection against infectious
diseases and cancers -- turn on the body itself.
When anti-self immune responses destroy the insulin-producing beta cells of
the pancreas, diabetes is the inevitable result. Scientists have known this for
many years. But they have never found a way to call off the dogs. Yet.
It's possible that immune treatments trials now under way could find the
"off" switch to diabetes autoimmunity. Researchers reported progress at
the American Diabetes Association's 67th Annual Scientific Sessions, held June
22-26 in Chicago.
Teaching Tolerance to Haywire Immune Responses
Diabetes anti-self immune responses often have a specific target -- a
pancreatic enzyme called GAD. A vaccine called Diamyd incorporates an
artificial GAD protein. The idea is to induce immune tolerance to GAD.
Immune tolerance is a natural process. But it's been immensely hard for
researchers to induce it. The idea is to expose a person to just enough of a
substance to help the immune system recognize it as normal. If too little is
used, nothing happens. If too much is used, it can trigger even more harm.
Ake Lernmark, PhD, of the University of Washington in Seattle and Lund
University in Malmo, Sweden, noted that clinical studies seem to have
identified just the right dose of Diamyd to induce GAD tolerance.
Trials suggest that the vaccine may be able to stop autoimmune destruction
of insulin-producing pancreatic beta cells.
Diamyd "has a clear and statistically significant protective effect on
residual insulin function," Lernmark said. "It is effective, safe, and
Unfortunately, a recent clinical trial of Diamyd had to be stopped when
investigators somehow got doses of the real vaccine mixed up with doses of
inactive placebo. A new phase III clinical trial is now enrolling patients.
Switching Targets in Midstream
The breakthrough in diabetes immune therapy may come from left field -- that
is, from the field of multiple sclerosis.
Northwestern University researcher Stephen D. Miller, PhD, usually works on
autoimmune responses in multiple sclerosis. But his team's findings appear
extremely relevant to diabetes.
The basic problem with teaching tolerance to self-reactive immune responses,
Miller finds, is that once these immune responses become tolerant to one self
target, they find a new self target.
That helps explain a lot of immunologists' frustration. Fortunately, Miller
and colleagues find that it's possible to stay one step ahead of the immune
system. Anti-self immune responses, Miller reports, tend to follow predictable
By using spleen cells to carry specific target peptides (protein building
blocks) to the immune system, Miller's team has stayed one step ahead of the
"Tolerance can be induced using spleen cells coupled with a cocktail of
peptides," he says. "This is a very effective way to induce
Animal tests are under way to see whether this concept works for diabetes.
Meanwhile, Miller's team is planning early clinical trials of the approach in