Bubble-Free

The two infants, 11 months and eight months old, suffered from a rare life-threatening disorder called severe combined immunodeficiency. Because a genetic mutation kept their immune systems from fending off even the most innocuous infections, both faced lifelong confinement in sterile shielded environments. Now, 10 months after undergoing treatment in France to correct the defect, these "bubble babies" are out of their bubbles--back at home and acting for all the world like normal babies.

Doctors have successfully treated many young SCID patients before with various types of bone-marrow transplants. What distinguishes these two babies, researchers reported in Science last week, is that they are the first to be treated, apparently successfully, entirely by gene therapy. Says Dr. Alain Fischer, who headed the gene team at Hopital Necker-Enfants Malades in Paris: "Preliminary evidence is of a faster and more complete immune reconstitution after gene therapy."

Typically, gene therapists use viruses to deliver replacement genes into a patient's body. In a slight variation on that strategy, Fischer and his colleagues removed some of the children's bone marrow, sorted out the cells they needed and infected them with the gene-bearing virus. Then the researchers injected the treated cells back into their young patients. Within two weeks, the children started showing signs of a healthy immune system.

The true test will come as doctors at other medical centers try to replicate Fischer's treatment. No one wants to sound too optimistic, particularly in light of the death from an unrelated gene therapy of an American six months ago. But for SCID at least, it's starting to look like gene therapy could be a winner.