The Bubble Boy's Lost Battle

David's death may be a clue to a strange disorder

It had been his simple wish to walk barefoot on the grass and some day to live normally in the world. For this hope David, 12, and his family took the ultimate gamble: they traded the safety of a germ-free plastic bubble at Houston's Texas Children's Hospital for the slim chance that a bone-marrow transplant would allow the immunologically defenseless boy to live freely. Last week they lost their gamble, and his death was felt across the country.

David's case was unprecedented: no other human being had lived so long without a functioning immune system, a defect that can turn even the common cold into a fatal disease. David (the family always insisted on anonymity) owed his survival to doctors who had anticipated the condition before his birth because an older brother had died of immunodeficiency. Inside a series of sterile "bubbles," David progressed from a baby in a crib to an A student who attended school by telephone; his food was sterilized and slipped in through air locks. Only briefly, in 1977, was he able to explore the world outside, thanks to a special suit presented to him by NASA. More than a million dollars in federal research grants helped cover the cost of his care.

The only hope for a cure was a transplant of bone marrow, which could provide the body with a rapidly multiplying source of defender cells to ward off disease. Such transplants were once possible only if a genetically matched donor, generally a sibling, could be found. Sadly, David's older sister's cell type did not match his. In the past few years, however, new technology has made it possible to transplant imperfectly matched marrow, making obsolete the isolation approach to David's illness. "There will be no more bubbles," said Dr. William Shearer, the boy's physician. Last October David received 1 2/3 oz. of his sister's treated marrow.

On Feb. 7 David finally emerged from his sterile world, crawling through an air lock into his mother's waiting arms. But that brief reunion was clouded by worry: a persistent fever, diarrhea and vomiting had made it necessary for doctors to treat him outside the bubble. The symptoms, doctors feared, were signs of the often fatal graft vs. host disease, which occurs when cells from donated marrow attack the recipient's body. During the next 15 days, David developed severe ulceration of his digestive tract and a dangerous accumulation of fluid in his lungs and around his heart. The exhausted child finally died of cardiac failure. Shearer recalled that at the end David asked, "Why don't we just pull out all these tubes and let me go home?"

Post-mortem examination disclosed "totally unexpected" complications, according to Shearer. Accumulations of abnormally large white blood cells known as B cells were found in the boy's intestines, lungs and spleen. The fact that the cells were David's and not his sister's suggested that the transplant had not taken hold. For doctors, the more interesting question was whether these cells were malignant. The answer could provide valuable clues to the immune system and how it defends against cancer. "David's life," said an emotional Shearer, "has been important for medicine, but his greatest contribution was his death." qed