Transcripts
DR. ROCK:
Now, there's been a long history
of attempts of therapy of this or these
disorders. In 1925, Moschowitz first described
the disorder and attempted treatment by a variety
of methods which led, in 1924, Lederer to use
simple blood transfusion and, in fact, achieve
some response with an elevation of platelet
counts. This led Rubenstein, in 1959, to carry
out exchange procedures with whole blood.
Now you can just imagine that a
normal whole blood collection at that time would
be about 400 hundred ml's, and so in order to
replace a blood volume of let us say four liters
or five liters, this would be an extremely time
consuming, tedious and difficult procedure, but
nonetheless, it was tried, and with some
reasonable success leading Bukowski, in 1977, to
consider carrying out exchanges but now using
fresh frozen plasma.
Then, of course, the machines
came along. And while the machines were
originally developed and certainly the first use
I ever had for them was for collecting white
blood cells to transfuse to septic patients,
it was very, very early in the
game we recognized that if we could take and
separate the cells from Apheresis procedure we
could just as well remove the plasma so the
field of plasma Apheresis or plasma exchange
began.
So Bukowski's work, in 1977, led
to the consideration of the use of fresh frozen
plasma. And we began the study in the mid
`80s, in Canada, in which we compared plasma
exchange to plasma infusion in the treatment of
adult patients with acute TTP.
It took us a number of years to
get this data published because it took us a
long while to really make sure that we could
recruit all the patients, get the information
across what is essentially a long skinny country.
But in 1991, we published data in the New
England Journal of Medicine indicating that
plasma exchange was preferable to plasma infusion
in the treatment of these patients.
Now we acknowledged the fact
that we did not use as much plasma in the
plasma infusion arm as we did in the exchange
arm, but that's simply because we used the
maximum dose that could be tolerated by the
patients. We were not so much interested in
looking at volumes of plasma as a therapy but
modes of treatment.
Then, in 1991, Byrnes published
a case report in which he used a different kind of
replacement fluid, cryosupernatant plasma, to treat
these patients leading us then, after we finished
our first study, to then look at the use of
cryosupernatant plasma versus fresh frozen plasma
in plasma exchange and found, again, a
superiority of the latter treatment.
