Compound stops autoimmune response in diabetes
A compound that might be useful for treating autoimmune
diseases mediated by pathogenic T-helper type 1 (Th1) cells has been identified.
Type 1 diabetes is one of the diseases characterised
by an uncontrolled Th1 response. The compound, a-galactosylceramide (a-GalCer),
activates natural killer T cells which are known to have immunoregulatory
effects.
Dr Seokmann Hong, Vanderbilt University School of
Medicine, Tennessee, and colleagues say that a-GalCer potentiates the
T-helper type 2 (Th2) adaptive immune response. This gives protection
against the effects of Th1 cells thus preventing the development of the
autoimmune disease. The researchers found that administration of a-GalCer
prevented development of diabetes in mice. The researchers comment: “a-GalCer
might be useful for the treatment of a variety of diseases that are mediated
by pathogenic Th1 cells.” They add: “Our findings identify natural killer
T cells as novel targets for immunotherapy.” (Nature Medicine 2001;
7:1052.)
A second group of researchers also has evidence
to support the role of a-GalCer in preventing diabetes through activating
natural killer T cells (ibid, p1057). They report: “a-GalCer treatment
protects female non-obese diabetic mice from type I diabetes.”
In addition, they found that a-GalCer prolonged
the survival of pancreatic islets transplanted into newly diabetic non-obese
mice. Transplanted grafts survived for 22 weeks in mice treated with a-GalCer
compared with 10 days in a control group.
They suggest that the treatment might be useful
in preventing diabetes both at an early stage and later on, after the
onset of insulitis. It could dampen the recurrent autoimmune response
in patients with diabetes who receive islet cell transplants, they add.
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