Quote:
Originally Posted by Nicknerd
I tend to see people with autoimmune diseases as having 'weak' immune systems. They seem to be more prone to infection than those who have 'normal' immune systems.
As an example, I decided to look up 'thymus and HIV' just out of curiousity one day. There seemed to be quite a few cases of people with HIV developing Myasthenia gravis and Lupus-like syndromes. In fact, some doctors were proposing that Myasthenia gravis in HIV patients be considered a disorder that sometimes comes with seroconversion. I don't know if this is happening because of molecular mimickry, in which case, it might not be indicative of a 'weak' immune system, but something a bit different, or because the immune system is being destroyed somehow and making it act wacky, or even both. There was actually a study done comparing the thymuses of deceased HIV patients to those of people with MG who had thymectomies. Pathologically, the thymuses were very similar. To me, this translated to autoimmunity being a sign that the immune system is really weak, or injured in some way.
Sorry to have diverted the subject a bit! Just wanted to share that bit of info.. I found it really interesting!  |
Nicky,
you are perfectly right. it is not longer thought that autoimmune disease are the result of an "hyperactive" immune system. in fact HIV has taught us quite a lot with regards to that. because it came as a great surprise that people that clearly have immune deficiency, also have a much higher prevalence of autoimmune disease.
in fact the more accurate way to see it is as dysregulation of the immune system. the immune system can be seen as an "army" which is fully equipped to attack any possible "invader". because of that it has to be kept under very tight control. we are very far from fully elucidating the very complex mechanisms invovled, but at least we know that we don't know.
there are basically multiple sub-populations of lymphocytes that are responsible for that, and we are constantly discovering more. in the past it was thought that there are T helper cells (CD4+, which are the ones that are low in HIV) and T supressor cells (CD8+) we now know that it is much more complex then that. and some of the T helpers are actually T regulators, and only appear to belong to the same population when in fact they have very different roles.
there are many new treatment approaches that try to modulate the immune system better. "tackling" what is wrong and not just "shooting" blindly at all the immune cells and other innocent bystanders. the first among which was rituximab which is a targeted therapy aimed at destroying only those cells that produce antibodies (B cells). the problem is that is not extremely efficient and also that it does not differetiate between normal B cells (which produce antibodies against pathogens that can attack us) and the abnormal ones (that produce the autoantibodies).
and in fact there is a lot of interest in trying to find various "natural" products such as green tea, curcumin etc, that are known to have an effect on the immune system, and utilize them as less toxic agents.
and I can tell you that herbalists can be just as arrogant as physicians, and some refuse to give away their "secrets" and join forces in this type of research.
alice