Newsgroups reorganised, subject changed.
Boron Elgar <[email hidden]> writes
Quoted message said:
This makes sense insofar as the way certain allergy treatments are done... with repeated low dose
exposure to allergens to build resistance.
Hmmm. Of course you are trying to do the exact opposite here. That is you are trying to prevent a
completely inappropriate and excessive immune response to a harmless chemical.
It gets a little more complex here, even in this simplified explanation, but there is now very
considerable evidence that continued lack of exposure to bacterial challenge predisposes people to
allergies. The effect was noticed when several large scale studies by different groups showed that
those with a high exposure to pathogens (particularly as infants) had low or near zero incidence of
allergies. Its almost unknown in the third world and firstborn in the first world are much more
likely to have allergies than second and subsequent born.
The mechanism proposed for this is again a fairly simple one. There are essentially two immune
response mechanisms in mammals. One targets bacteria and the other viruses and toxins. The two are
mutually inhibitory, that is when one runs full bore, the other is suppressed. In the absence of a
challenge this is clearly an unstable situation, but in 200,000,000 years of evolution that has
never been a problem because bacterial challenges happen every day but viral and toxin challenges
are rare. Until hygienic man came on the scene, who lives in a completely unnatural sterile
environment. Now the lack of challenge due to bacteria means the toxin response is not continually
inhibited so it becomes hyperactive and can (and does) mount a full-blown lifesaving-at-all- costs
response to very minor exposure to mild (or even harmless) toxins.
There are quite a few refs to this now. For a very old one try googling 'let them eat dirt' on the
new scientist website.
Also, in passing, the treatment of some allergies by infection with intestinal worms seems to be
very effective, although few would want this treatment unless their allergy was extreme (but
some are).
I find this all very interesting.
Quoted message said:Even with vaccination, such as for measles, they are now realizing that the vaccines used for a
long time did not confer lifetime immunity, but required boosters in early adulthood.
That's not quite what I heard.
Many (perhaps all) lifetime immunities are conferred by the virus NOT being eradicated from the body
after the first infection. Chicken pox, for example, ends up in some nerves where it remains but
highly suppressed. When infected people get old and/or get sick so their immune response drops it
flares up to give shingles.
Now some vaccines (eg the OLD polio vaccine) are live 'weakened' vaccines, and the virus quickly
reverts to the active form after vaccination. However it has a very slow start and by the time its
becomes fully virulent the body has already mounted an immune response and stomps it out before
clinical symptoms occur. Typically these give lifetime response if there is a lifetime response to
that pathogen.
Some are dead viruses. The body mounts a (modest) response, which is fine. However in the absence of
further challenges the response slowly decays. At some point it falls so far that the immunity no
longer effective. Now in days gone by this wasn't a problem because *everyone* got exposed to the
wild virus sooner or later (and usually sooner). In the first world this no longer happens.
That's probably enough for this post.
--
Oz This post is worth absolutely nothing and is probably fallacious. DEMON address no longer in use.