Tyson wrote:
>> ....there is also new evidence that cryptopatches in the gut are extrathymic
> maturation sites for T-cell precursors....no need for a thymus....which
> explains the mintenance of T-cell repertoire in an athymic individual
>> Gordon MacPherson <gordon.macpherson at path.ox.ac.uk> wrote in message
> news:382300DA.DC962C77 at path.ox.ac.uk...> | Recent evidence in humans shows that even when the thymus is apparently
> | involuted in adults, it is still actively producing T cells.
> |
> | Gordon
> |
> | vborde at my-deja.com wrote:
> |
> | > Hello everyone
> | > I would like to know what happens to a T-cells population (repertoire)
> | > when the thymus becomes non-functional, at the adult phase? Does this
> | > person lose all of her matured T-cells? Does she also lose her self
> | > tolerance and become vulnerable to autoimmune diseases? How does she
> | > keep her T-cells? Thank you.
> | >
> | > Sent via Deja.com http://www.deja.com/> | > Before you buy.
> |
That there is no need for a thymus is probably overstating it.
Otherwise DiGeorges would not have immunodeficiency as a component of
the syndrome. It would be surprising if these patches are
developmentally related to Pharyngeal pouch development.
The original post also assumes that tolerance is solely a function of
thymic conditioning. This is not the case as there are mechanisms for
peripheral tolerance. Recent models suggest that this somehow involves
DC subpopulations.
--
Paul U Cameron
