Posted by Gabrielle on February 07, 2001 at 22:11:08:
In Reply to: Type 1 onset under the age of 5 posted by Therese B. on February 05, 2001 at 13:23:37:
This is a really tough one, but I agree that it will be an important question to address. I can't think of any full proof way of showing this right now. Something along the lines of the paper below might work. One could then test the blood against a small sample of prospective beta cells and look in a sample of the peripheral blood for activation of T-cells (secretion of cytokines) when exposed to the cells.
In the case of modulating islet growth in vivo, I think that one could try and simply monitor the blood. If the T cells activate, then one would initiate immunosuppression. I agree that lack of autoimmunity could make a big difference assuming that whatever it was that killed the beta cells in the first place was environmental and not genetic. That said, there are not too many cases that I know of where type I diabetes improves with time, and given that some in vivo regeneration seems possible, it seems likely that the damage is ongoing in most cases.
In terms of what is available now, antibody tests and DR/DQ haplotyping would probably give at least some suggestion if they are positive.
Because the class I and class II molecules would be different in an allograft, the host T-cells which would initiate an autoimmune response would very likely not be the same ones which would recognize a foreign MHC-peptide. Hence in the allograft context, autoimmunity would probably be less important, but covered in any event by the heavier immune suppression which is needed.