Diabetes aurtoimmunity seen, stopped.

Diabetes Autoimmunity Seen, Stopped

Early use of a potent immune-system suppressor could stop the destruction of insulin-producing cells in diabetics, some of whom may then be able to discontinue insulin injections, according to reports this week on two recent clinical trials. Scientists say the findings, based on studies with the drug cyclosporine, strongly support the theory that diabetes is an autoimmune disease.

At this week's international confermence on diabetes in St. Louis, John Dupre of the University of Western Ontario in London presented the results of a clinical trial using cyclosporine to treat type I diabetes. The most severe form of the disease, type I diabetes usually begins during childhood or adolescence, and currently affects about 1 million patients in the United States. Symptoms appear when islet cells in the pancreas stop producing enough insulin to process sugar, and treatment generally requires repeated insulin injections.

In a recently completed study of 188 patients at 12 diabetes centers in Canada and Europe, cyclosporine "unequivocally' increased the rate of remission, Dupre told SCIENCE NEWS. "At one year,' he says, "about 25 percent of the patients on cyclosporine are off insulin, compared to about 10 percent on the placebo.' The group also noted that patients treated earlier (within two weeks of beginning insulin use) did better, with 30 percent in remission compared to 3 percent of the controls.

These results follow a preliminary stody reported in 1984, in which Dupre and his co-workers had found that about half the 41 diabetics tested could discontinue insulin therapy if given cyclosporine, a drug normally used to suppress organ rejection following transplantation. This "unexpectedly high rate of remission' persisted during the yearlong study, says Dupre. He adds, however, that because most patients relapsed after cyclosporine therapy stopped, such therapy likely would have to continue indefinitely.

Another clinical trial, at the St. Vincent de Paul Hospital and other institutions in Paris, supports the concept that early intervention with cyclosporine gives better results. The scientists presented their data at the Second International Congress on Cyclosporine this week in Washington, D.C. Of 40 patients given cyclosporine, 27 were able to discontinue insulin injections an average of 48 days after the onset of therapy. The results indicate that those who did not respond had had the disease longer.

Encouraged by such results, some scientists are asking whether cyclosporine therapy should be started immediately after the diagnosis of type I diabetes, to halt additional destruction of islet cells by what appears to be an autoimmune response. But the answer is complex, says Robert E. Silverman, chief of diabetes programs at the National Institutes of Health in Bethesda, Md. He said in an interview that "the data are good, but what they mean is still very much an issue of debate in the [scientific] community.'

He is concerned that physicians will treat young diabetics with cyclosporine, which can be toxic and is approved worldwide only for transplantation use and treatment of an eye disease. This, coupled with the probability that cyclosporine therapy in diabetes must continue for the life of the patient, could affect cyclosporine's usefulness in this disease, even though doses given diabetics may be lower than those used following transplants. Silverman compares this use of cyclosporine, with its broad immunosuppression, to hitting "a bull's-eye with a bazooka.' This form of immunotherapy for diabetes may be quite practical in the future, he adds, "but probably . . . with a drug more specific to . . . diabetes.'