For 30 years, Jon Newton
has lived with Stevens-Johnson Syndrome (SJS), a rare
and serious disorder that causes inflammation of the
body's mucous membranes. The impact on his eyes was
so severe that he became legally blind, able to count
only fingers held up two feet in front of him. About
40 operations on his eyes did nothing to restore his
sight. But a remarkable new procedure, in which cells
from a healthy eye are harvested and transplanted, paved
the way for a successful cornea transplant.
Mr. Newton was 16 when
he contracted SJS, an autoimmune disorder triggered
by an allergic reaction to certain medications. Two
weeks after he took phenobarbital and dilantin, a rash
broke out on his arm. His doctor took him off phenobarbital,
but the next day blood blisters broke out all over his
body, and he had a high fever.
"I was in an intensive
care unit for three weeks," says Mr. Newton. "I
had a horrific reaction that made its way throughout
The corneas of Mr. Newton's
eyes, once clear and healthy, became clouded and scarred.
His eyes were excessively dry, and eyelashes were growing
into the eyelids. One surgical attempt to restore moisture
in his eyes involved transplanting salivary glands to
replace defective tear glands; the procedure produced
only "two years of pain." Neither electrolysis
nor a freezing process to remove the invading eyelashes
Other operations throughout
the years had not helped, and Mr. Newton had little
hope that his vision would be restored. That is, until
his sister found information on the Internet about limbal
stem cell transplantation.
from the 'Mother' Cells
Very few people have
Stevens-Johnson Syndrome, but anyone who uses chemicals
at work or home, is injured by fire, or is a long-term
wearer of contact lenses might some day benefit, as
Mr. Newton has, from limbal stem cell transplantation.
A chemical splash to the unprotected eye can wipe out
the eye's outer surface.
According to Prevent
Blindness America, 2,000 workers suffer eye injuries
on the job every day. Wearing poorly fitting contact
lenses over time can also deplete the supply of limbal
stem cells. Certain inflammatory diseases can lead to
damage and loss of limbal stem cells.
Here's why limbal stem
cells are so important. The eye's cornea is the clear
tissue that allows light to enter the eye. In addition,
it refracts light rays to focus onto the retina. The
cornea's outermost section, the epithelial layer, acts
as a protective barrier against germs and dust.
Between the cornea and
the sclera, the eyeball's white outer coating, is the
limbus, where some very important cells reside. Limbal
stem cells are "mother cells" that give rise
to the corneal epithelial cells. Severe damage to limbal
stem cells, whatever the cause, significantly impairs
a person's vision, says Dr.
David Chu, assistant professor of ophthalmology
and director of the ocular immunology and corneal wound
healing unit of the division of corneal and external
disease at the New Jersey Medical School.
"When the outer
eye surface is destroyed and if the limbus is damaged,
the corneal surface becomes populated by abnormal epithelial
cells," he explains.
"Without the proper
corneal epithelial cells, the cornea's surface is no
longer smooth, but instead becomes cloudy or scarred.
It is unable to properly refract light, significantly
impacting the person's ability to see."
Limbal stem cell transplants
emerged in the 1970s, but few were done until about
five to 10 years ago, says Dr. Chu, who received fellowship
training in ocular immunology, cornea, and external
disease at the Massachusetts Eye and Ear Infirmary of
Harvard Medical School.
limbal cells being taken from the donor eye.
limbal stem cells being transplanted.
The limbal stem cells
are taken from the healthy eye of the patient, if one
exists, or a live donor--usually a sibling or a parent.
(The donor eye can function with fewer limbal stem cells.)
Less often, limbal stem cells are taken from a cadaver.
An emerging approach uses a fraction of the amount of
limbal stem cells normally taken from a live donor and
grows them in the laboratory.
During this outpatient
procedure, which lasts about one hour, some limbal stem
cells are taken from the healthy eye or the donor's
eye and then transplanted to the affected eye. If the
transplant is successful, the limbal stem cells will
produce a new layer of epithelial cells in the patient's
eye. The success rate of growing the new cells from
transplanted limbal stem cells varies from 25 percent
to 70 percent, depending on the underlying condition
of the eye.
In some cases, a limbal
stem cell transplant alone can make a patient's vision
considerably better. For other patients, the limbal
stem cell transplant sets the stage for what follows
-- a cornea transplant.
There are about 40,000
cornea transplants performed each year, which typically
are very successful. Multiple eye surgeries and conditions
such as keratoconus, where the normally round cornea
thins out and becomes cone shaped, and Fuch's Dystrophy,
an inherited disease of the eye that causes corneal
swelling, can lead to the need for a cornea transplant.
Limbal stem cell transplants aren't necessary prior
to a cornea transplant where the limbus is intact.
However, says Dr. Chu,
cornea transplants will universally fail without the
presence of healthy limbal stem cells to give rise to
the corneal epithelial layer. For patients with SJS
or other immunologically initiated diseases involving
the ocular surface, or those whose eyes have been injured
by chemicals or fire, the limbal stem cell transplant
precedes the cornea transplant.
"We wait about three
months after the limbal stem cell transplant before
attempting a cornea transplant," says Dr. Chu,
who performs both procedures at University Hospital.
"If there has been injury or damage to other parts
of the eye--the lens, the retina, or the optic nerve,
for example--other ophthalmic procedures may be needed
to address those problems."
After Mr. Newton's sister
read about limbal stem cell transplantation, he decided
to give it a try. Because his right eye was damaged
beyond repair, the transplant was for his left eye.
Another sister was a good genetic match and agreed to
be the donor. Dr. Chu, a specialist in treating visual
manifestations of Stevens-Johnson Syndrome, was part
of the team that performed Mr. Newton's successful limbal
stem cell transplant on January 22, 2001. In April,
the same doctors performed a cornea transplant on Mr.
Newton, who today has 20/30 vision.
Having his sight restored
after 20 years of being legally blind is "awesome,"
says the 46-year-old Mr. Newton. "One of the most
awesome sights is to go outside at night and see the
stars again. I just look up, and there are the stars."
information about limbal stem cell transplant or to
make an appointment with Dr. Chu, call The Department
of Ophthalmology at (973) 972-2065.