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A washingtonpost.com article from doris45@...

>You have been sent this message from doris45@... as a courtesy of the

Washington Post (http://www.washingtonpost.com).

>

>To view the entire article, go to

http://washingtonpost.com/wp-dyn/articles/A28967-2000Apr27.html#top

>

>Genetic Therapy Apparently Cures 2

>

>

>Two infants born with a life-threatening immune system disorder that had

forced them to live inside protective sterile " bubbles " are healthy and

living normal lives almost a year after being treated with an experimental

genetic therapy, doctors reported yesterday.

>

>If the children retain their good health, they will go down in medical

history as the first to be definitively cured by gene therapy, a

controversial approach that seeks to treat diseases by giving people new

genes.

>

> " They have complete restoration of immune system function, " said Marina

Cavazzana-Calvo of Necker Hospital in Paris, who led the research with

co-worker Alain Fischer. " The word 'cure' is hard to use because we don't

know how long these results will last. But the follow-up of one year is very

encouraging. "

>

>Cavazzana-Calvo said the team has recently treated three additional

infants, including one from the United States, and at least two of them

appear to be completely healthy. The children's identities are not being

released, to protect their privacy.

>

>Experts in this country said they could hardly contain their excitement.

" This is something you dream about, " said Shearer, chief of

immunology at Texas Children's Hospital in Houston. Shearer, also of the

Baylor College of Medicine in Houston, was one of the doctors who in the

1970s and 1980s cared for the " Bubble Boy, " who suffered from the same

disease as the French children and died in 1984 at the age of 12.

>

>The French results, Shearer said, " are fabulous. "

>

>In the 10 years since a 4-year-old Ohio girl with a related immune system

disorder became the first person to be treated with gene therapy, doctors

have tried to deliver curative genes to thousands of patients with many

different diseases, all to no avail. In 1995, a federally appointed panel

criticized scientists for experimenting on too many people before enough

basic research had been done.

>

>In September, the field came under renewed public scrutiny and criticism

when a teenager died in a University of Pennsylvania experiment that federal

regulators concluded was badly managed. Congressional inquiries later

revealed hundreds of lapses in similar studies being conducted around the

country.

>

>The new work, described in today's issue of the journal Science, could give

the beleaguered field a boost by proving for the first time that gene

therapy can correct inborn genetic errors.

>

> " It looks like gene therapy is beginning to turn the corner, " said W.

French , who led the first gene therapy experiment in the United

States while he was at the National Institutes of Health in 1990.

>

> " We're not talking about treatments for lots of diseases in the next few

years, " said , now at the University of Southern California. " But

this is certainly good news for patients, because until now we had

essentially zero success. "

>

>All the children treated by the French team were born with a rare and

catastrophic disease called SCID-X1, in which a single defective gene

disables T cells, which are crucial to the body's ability to fight

infections. The disease can be cured with a bone marrow transplant from a

healthy donor, but only in a minority of cases are donors available with a

full genetic match for the patient.

>

>Taking a different approach, the French team removed bone marrow from its

young patients, who ranged from 1 month to 11 months old. Bone marrow

contains blood " stem cells, " which produce a constant supply of immune

system cells that migrate into the bloodstream and circulate for months or

years before dying and being replaced.

>

>The researchers removed millions of stem cells from each infant's marrow,

used genetically altered viruses to deliver to those cells healthy copies of

the gene the children lacked, and then reinfused the newly endowed stem

cells into the children.

>

>The hope was that those repaired cells would settle into the bone marrow

and produce genetically corrected immune system cells for the rest of the

children's lives.

>

>Within 15 days, tests indicated that some of the children's circulating

blood cells did indeed contain the gene that had previously been missing.

Over a period of months, the number of circulating immune system cells

increased, and tests indicated that for the first time, large numbers of

them were functioning normally.

>

>Most encouraging, the children became healthy. Chronic diarrhea and

long-lasting skin sores disappeared. When the children were inoculated with

tetanus, diphtheria and polio vaccines, their immune systems responded

normally and produced antibodies against those childhood infections, which

otherwise could easily kill them. Four of the five treated children have

left their protective isolation tents and are living in their homes, where

they are developing normally.

>

>Key to the therapy's apparent success, scientists said, were recent

improvements in gene-transfer techniques that ensure that a greater number

of stem cells get copies of the healthy gene. Moreover, the repaired stem

cells seem to have a " selective advantage, " or better survival, compared

with unrepaired cells, and so are gradually coming to dominate in the

children's marrow.

>

>Nonetheless, researchers cautioned, animal studies have shown that new

genes added to cells via viruses can gradually become inactive over a period

of years. If that happens, the children would have to be isolated in bubbles

again, and perhaps be treated again.

>

>Cavazzana-Calvo said the same technique, using viruses loaded with

different corrective genes, may prove curative for other diseases. But it

would be appropriate only for diseases in which overproduction of the

missing gene would not be harmful, because there is no way to regulate the

activity of a newly inserted gene once it is in the body.

>

> said he hoped to try the new technique this summer in Ashanthi

DeSilva, the Ohio girl he first treated as a 4-year-old in 1990, and who has

a form of SCID called SCID-ADA. About 25 percent of DeSilva's immune system

cells were repaired as a result of that initial treatment--until now, the

most successful use of gene therapy--but she still relies on regular doses

of a powerful and expensive drug that enhances the immune system.

>

>

[Guest guest]

A washingtonpost.com article from doris45@...

>You have been sent this message from doris45@... as a courtesy of the

Washington Post (http://www.washingtonpost.com).

>

>To view the entire article, go to

http://washingtonpost.com/wp-dyn/articles/A28967-2000Apr27.html#top

>

>Genetic Therapy Apparently Cures 2

>

>

>Two infants born with a life-threatening immune system disorder that had

forced them to live inside protective sterile " bubbles " are healthy and

living normal lives almost a year after being treated with an experimental

genetic therapy, doctors reported yesterday.

>

>If the children retain their good health, they will go down in medical

history as the first to be definitively cured by gene therapy, a

controversial approach that seeks to treat diseases by giving people new

genes.

>

> " They have complete restoration of immune system function, " said Marina

Cavazzana-Calvo of Necker Hospital in Paris, who led the research with

co-worker Alain Fischer. " The word 'cure' is hard to use because we don't

know how long these results will last. But the follow-up of one year is very

encouraging. "

>

>Cavazzana-Calvo said the team has recently treated three additional

infants, including one from the United States, and at least two of them

appear to be completely healthy. The children's identities are not being

released, to protect their privacy.

>

>Experts in this country said they could hardly contain their excitement.

" This is something you dream about, " said Shearer, chief of

immunology at Texas Children's Hospital in Houston. Shearer, also of the

Baylor College of Medicine in Houston, was one of the doctors who in the

1970s and 1980s cared for the " Bubble Boy, " who suffered from the same

disease as the French children and died in 1984 at the age of 12.

>

>The French results, Shearer said, " are fabulous. "

>

>In the 10 years since a 4-year-old Ohio girl with a related immune system

disorder became the first person to be treated with gene therapy, doctors

have tried to deliver curative genes to thousands of patients with many

different diseases, all to no avail. In 1995, a federally appointed panel

criticized scientists for experimenting on too many people before enough

basic research had been done.

>

>In September, the field came under renewed public scrutiny and criticism

when a teenager died in a University of Pennsylvania experiment that federal

regulators concluded was badly managed. Congressional inquiries later

revealed hundreds of lapses in similar studies being conducted around the

country.

>

>The new work, described in today's issue of the journal Science, could give

the beleaguered field a boost by proving for the first time that gene

therapy can correct inborn genetic errors.

>

> " It looks like gene therapy is beginning to turn the corner, " said W.

French , who led the first gene therapy experiment in the United

States while he was at the National Institutes of Health in 1990.

>

> " We're not talking about treatments for lots of diseases in the next few

years, " said , now at the University of Southern California. " But

this is certainly good news for patients, because until now we had

essentially zero success. "

>

>All the children treated by the French team were born with a rare and

catastrophic disease called SCID-X1, in which a single defective gene

disables T cells, which are crucial to the body's ability to fight

infections. The disease can be cured with a bone marrow transplant from a

healthy donor, but only in a minority of cases are donors available with a

full genetic match for the patient.

>

>Taking a different approach, the French team removed bone marrow from its

young patients, who ranged from 1 month to 11 months old. Bone marrow

contains blood " stem cells, " which produce a constant supply of immune

system cells that migrate into the bloodstream and circulate for months or

years before dying and being replaced.

>

>The researchers removed millions of stem cells from each infant's marrow,

used genetically altered viruses to deliver to those cells healthy copies of

the gene the children lacked, and then reinfused the newly endowed stem

cells into the children.

>

>The hope was that those repaired cells would settle into the bone marrow

and produce genetically corrected immune system cells for the rest of the

children's lives.

>

>Within 15 days, tests indicated that some of the children's circulating

blood cells did indeed contain the gene that had previously been missing.

Over a period of months, the number of circulating immune system cells

increased, and tests indicated that for the first time, large numbers of

them were functioning normally.

>

>Most encouraging, the children became healthy. Chronic diarrhea and

long-lasting skin sores disappeared. When the children were inoculated with

tetanus, diphtheria and polio vaccines, their immune systems responded

normally and produced antibodies against those childhood infections, which

otherwise could easily kill them. Four of the five treated children have

left their protective isolation tents and are living in their homes, where

they are developing normally.

>

>Key to the therapy's apparent success, scientists said, were recent

improvements in gene-transfer techniques that ensure that a greater number

of stem cells get copies of the healthy gene. Moreover, the repaired stem

cells seem to have a " selective advantage, " or better survival, compared

with unrepaired cells, and so are gradually coming to dominate in the

children's marrow.

>

>Nonetheless, researchers cautioned, animal studies have shown that new

genes added to cells via viruses can gradually become inactive over a period

of years. If that happens, the children would have to be isolated in bubbles

again, and perhaps be treated again.

>

>Cavazzana-Calvo said the same technique, using viruses loaded with

different corrective genes, may prove curative for other diseases. But it

would be appropriate only for diseases in which overproduction of the

missing gene would not be harmful, because there is no way to regulate the

activity of a newly inserted gene once it is in the body.

>

> said he hoped to try the new technique this summer in Ashanthi

DeSilva, the Ohio girl he first treated as a 4-year-old in 1990, and who has

a form of SCID called SCID-ADA. About 25 percent of DeSilva's immune system

cells were repaired as a result of that initial treatment--until now, the

most successful use of gene therapy--but she still relies on regular doses

of a powerful and expensive drug that enhances the immune system.

>

>