Boy’s transplant success offers hope
Sickle cell disease is a painful and life-threatening genetic condition that affects about 70,000 people in the United States and more than 600 Pittsburgh-area residents, most of whom are black.
Healthy red blood cells are round and jelly-like, squeezing easily through even the smallest capillaries in the body.
In sickle cell sufferers, however, red blood cells become misshapen because they contain an abnormal type of hemoglobin, the protein that delivers oxygen from the air in the lungs to all parts of the body. These deformed cells are hard and crescent-shaped, like sickles used to cut wheat.
One in eight black Americans carries a single copy of the gene for sickle hemoglobin, which likely evolved as a defense against malaria. Carrying one copy of the gene does not cause health problems. But if two carriers like Sarah and Anthony Jones, of Indiana, Indiana County, have a child, there’s a 25 percent chance that the child will inherit the disease.
“At first we thought, ‘What did we do to our child?'” said Sarah Jones, whose youngest son, Austin, 6, was born with sickle cell disease. “Then we quickly realized that we needed to be thinking instead about what we could do for our child.”
Sickle-shaped blood cells block small blood vessels, depriving tissue and organs of an adequate oxygen supply. This can cause lung and spleen damage, severe anemia, episodes of excruciating pain, kidney failure and stroke.
People with sickle cell disease often rely on heavy-duty narcotics for pain relief and frequently must receive blood transfusions to improve their circulation. Most do not live past their mid-40s.
Transplanting bone marrow — the body’s blood-making factory — of a healthy person is the only way to cure sickle cell disease. But bone marrow transplants carry their own dangers and are only offered to sickle cell patients in the most serious cases.
Patients must be treated with massive doses of chemotherapy to kill off their own defective bone marrow and take hard-to-tolerate immunosuppressant drugs to stave off rejection of the transplanted cells.
Worldwide, only about 210 sickle cell patients — and fewer than 70 in the United States — have undergone bone marrow transplants for sickle cell disease because of the high risk of potentially deadly fever and infection, said Dr. Lakshmanan Krishnamurti, a hematologist at Children’s Hospital of Pittsburgh. Transplant can be fatal in 5 percent of cases and fail to cure the disease in another 10 percent, Krishnamurti said.
But these odds are improving.
Five years ago, Krishnamurti became the first physician in the world to perform an innovative new transplant protocol intended to prevent complications from occurring in sickle cell patients.
The procedure uses gentler doses of chemotherapy so the patient’s own bone marrow is weakened, not destroyed. This minimizes the toxic side effects of the transplant, but requires higher doses of immunosuppressant drugs to prevent rejection.
Roughly 20 reduced-intensity transplants like this have been attempted worldwide, Krishnamurti said.
This procedure appears to have cured Austin Jones of his severe form of sickle cell disease. And since Austin’s surgery last July, Krishnamurti has performed reduced-intensity bone marrow transplants on two more sickle cell patients, one child and one adult. Early results are promising, he said.
“I’m thrilled,” Krishnamurti said. “What we’ve learned by treating Austin we could use to treat people who wouldn’t otherwise qualify for transplant. That’s where the real excitement is.”