Posted by Mary E. on June 02, 1999 at 15:35:28:
In Reply to: Bone Marrow posted by Mary E. on June 02, 1999 at 15:28:45:
06/02 3:26P (RT) Marrow transplant breakthrough holds wider promise
chemotherapy, radiation therapy, and earlier bone marrow
transplants.
Bone marrow transplants have become standard treatment for
patients who are born with diseases of the blood, who have
their bone marrow fail or who have cancers such as leukemia
that originate in the bone marrow.
These patients "really didn't have any other treatment
option," said Guinan's co-author Dr. Lee Nadler. The new
technique involved paralyzing specific T cells. T cells are the
immune system cells that fight infection, stand guard against
cancer and attack foreign tissue.
One of the main complications of conventional bone marrow
transplants is graft-versus-host disease, a potentially fatal
condition in which T cells in donated bone marrow launch an
attack against recipients' tissue.
It was the first time the method, which has been known to
work in laboratory experiments for the past three-to-five
years, was used in humans.
"What we're doing with the new technique is to punch a hole
in the immune system - to paralyze the specific T cells
responsible for tissue rejection, but to leave intact those
that fight infection and guard against cancer," Nadler said.
The method involves removing some white blood cells from a
a patient and then treating the cells with chemotherapy and
radiation to kill off their immune system. Bone marrow is then
taken from a parent or sibling. The marrow and white blood
cells are combined along with a chemical, CTLA-4-Ig, made by
the Cambridge, Mass., biotech company Repligen Corp.
and incubated for 36 hours, Guinan explained.
The concoction is then transferred to the patient.
Seven of the 12 patients died after the procedure, but none
of the deaths was due to tissue rejection. Five of the 12 were
alive and in remission from 4.5 to 29 months after
transplantation.
The method, which Dr. Baruj Benacerraf, winner of the 1980
Nobel Prize in Medicine called "a pioneer work," significantly
extends the option of transplants to nearly everyone with a
partially matched donor such as a blood relative.
Guinan said the study was continuing and that further
research will be needed "to really prove the concept."