September 12, 2000
Research: Causes and Prevention
Question from Lewisville, Texas, USA:
I have read where Coxsackie virus can act as a trigger for type 1 diabetes. My two-year old son has had this virus twice. This concerns me. Is there anything I can do for my son to help his body stop attacking the beta cells? Is my son genetically disposed to type 1? Who knows? Various members of my family tend to be borderline (i.e., issues with blood sugar, tendency toward gestational diabetes, etc.), but no one has developed type 1 to date. My uncle is, however, insulin-dependent, but did not develop this condition until his mid-60s. I'm not sure whether his is type 1 or 2.
As I expect you already know, the onset of Type 1A or autoimmune diabetes is partly dependent on a genetic susceptibility which is mainly, but not exclusively, located in the HLA antigen region of the short arm of chromosome 6 and partly on an environmental factor. This latter has not yet been convincingly defined, though early exposure to certain kinds of cow’s milk is rather in vogue because of the well defined link between maternal rubella and subsequent diabetes in the infant, though it was to be expected that other viruses would be closely looked at for this role.
The difficulty, of course, is that the occurrence of a viral infection, in proximity to the development of clinical diabetes, may accentuate the final stages of autoimmune destruction of the beta cells, but it is no indication that it initiated the process nor indeed is the presence of viral antibodies any proof because the immune damage may have been triggered several years before its effects become apparent. Scandinavian researchers have paid particular attention to the possible role of Coxsackie B4 virus. They have shown that, in children with diabetes, T cell response to GAD, an antigen supposed to be an important trigger of autoimmunity, can be mimicked by purified Coxsackie B4 protein, a process called molecular mimicry. There is also some evidence that the virus first damages the beta cell which, in turn, provokes the autoimmune response in the normal way. All rather complicated!
Having had a Coxsackie infection, however, does not at all mean that autoimmunity has been invoked. Since there are steps that can be taken to defer insulin dependence, you might want to talk to your son’s doctor about getting an antibody test (telephone 1-800-525-8361 for some details). However, when you consider that his chance of developing autoimmune diabetes, when there is no first degree relative with it, is only about 18/100, 000 per year up to about age eighteen, you might feel you could settle for a ‘wait and see’ policy.
Your uncle might have what is called LADA (Late Autoimmune Diabetes in Adults, but it is far more likely to be type 2 diabetes. He is not a first degree relative though.