Children seriously ill because their immune systems have genetic¹ flaws could have their lives saved by a safer form of bone marrow² transplant, doctors say.

医生称，因基因缺陷导致病重的儿童可以通过更为安全的骨髓移植的方法来治疗。

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Without treatment, affected children have to live in sterile conditions

The London team says the treatment for so-called "bubble" children - who have to live in sterile（不毛的，不孕的） conditions - almost eliminates the need for chemotherapy（化学疗法）.

The Great Ormond Street doctors used antibodies to clear patient bone marrow（骨髓） and make room for donor⁵ stem cells.

They report in The Lancet the method cuts both rejection⁶ and side-effects.

High doses

Chemotherapy has both short and long-term consequences, ranging from hair loss to damage to organs such as the liver and lungs.

But it has been used as standard to kill the patient's own bone marrow and make room for stem cells.

This treatment has saved the lives of many children with serious genetic defects in their immune systems - primary immunodeficiencies（免疫缺陷） or PID - that render（提供，报答） even the most minor⁷ infections life-threatening.

Fifty such transplants are carried out each year.

But some children are deemed too sick to withstand（抵抗，对抗） the high doses of drugs needed to wipe out the bone marrow.

Gentler chemotherapy has been developed, but is still too much for certain groups of patients, such as babies.

Sickest children

The new technique, developed by doctors from Great Ormond Street and the UCL Institute of Child Health, uses an antibody that targets a molecule⁸（分子） specific to blood and bone cells - meaning other tissues are left undamaged.

The team led by Dr Persis Amrolia, reported that 13 of the 16 patients treated in the study had survived and been cured of their underlying⁹ disease.

They recovered twice as quickly as those given standard treatment, although there were still some complications.

"Because this approach was experimental, we only used it on the sickest children, who we felt could not tolerate standard transplant chemotherapy.

"Given how sick these children were before transplant, the results are remarkable," said Dr Amrolia.

"What's really encouraging is that pretty much all the children who survived now have a really good quality of life.

"There's still a lot to do and the challenge now is to develop similar targeted approaches for children with other genetic diseases and leukaemia（白血病）."

Chris Hughan, chief executive of The Primary Immunodeficiency Association, said: "We welcome this important study as it heralds¹⁰（预报，宣布） a potential breakthrough in the treatment of paediatric（儿科的） PID patients who need a bone marrow transplant (BMT) but have significant chronic¹¹ infection（慢性传染） or organ damage at the time.

The new treatment "provides a viable¹² alternative conditioning treatment for children unable to tolerate intensive transplant chemotherapy.

"We look forward to supporting this new BMT programme at GOSH and making our members aware of this exciting new treatment development."