He has had two dialysis treatments and will be having another one today.  His
bleeding has stopped and we are all hoping and praying for his recovery. It has
been a rough few days since all this happened.  

Thanks for your encouragement - it really helps.

Ora

I looked "Wright Antigen" up in OMIM (at PubMed), and followed some of
the links.

The OMIM entry called Wright a "private" blood system.  This term is
used for uncommon factors that are usually found in only a few
families.  It estimated the incidence of Wright A antigen in Caucasian
populations at about 3 in 10,000.

However, I found a paper that described an incidence of 1 in 1000 in
blood donors, and 1 in 56 blood donors had anti-Wright *antibody*.
There was a higher incidence of antibody in people with a long list of
conditions, including those that might have required blood
transfusions.  Post-partum women also had a higher incidence.

So either your relative has the Wright antigen and had the bad luck to
get a transfusion from somebody with the anti-Wright antibody, or vice
versa.  There are dozens of these rare traits, so they can't type for
all of them.  If we take the stats above, your relative ran into a 1 in
56,000 or perhaps much rarer event.  Perhaps Wright/anti-Wright is one
of those slow reactions that doesn't show up in a crossmatch.

Now that he knows, wearing a med-alert bracelet will make sure they
test for Wright antigen or anti-Wright antibody in any blood they
propose to transfuse into him in the future.  If he carries the Wright
antigen, it might be worthwhile for his close relatives to be tested,
and perhaps wear the med-alert bracelets too, since if the stats above
are good, they run a 1 in 56 chance of having a similar bad reaction if
they need a transfusion.

Caveat:  I'm not a doctor and I didn't do a real literature search.
But I hope the above helps.