> Wonder if a cause of crohn's or celiac disease could be caused by a lack
of
> the function performed by pinworms?

This is really great speculation and has been speculated by the experts in
the case of crohn's (celiac is really different from crohn's) only not with
pinworms but with bacteria. I have read that Crohn's is an over reaction of
the immune system due to an under reaction of another part of the immune
system. This over reaction goes after normal gut bacteria as well as
pathogens. They believe some bacteria ( forget which ones or wether they
know which ones) is esential, and actually "turns on geniticaly" a
particular aspect of the immune function. Also so many people with crohn's
have a propensity to make calcium oxalate kidney stones. It has been proven
that a bacteria in the gut (oxalobacter f. ) is lacking in the guts of us
who make stones.
The study with worms and crohn's did not produce a "cure" just a temporary
remission due to redirecting the immune system.