HLA-matched sibling transplants provide best outcomes in infantile osteopetrosis



Long-term survival after hematopoietic stem cell transplantation for infantile osteopetrosis was highest when grafts were taken from human leukocyte antigen (HLA)-matched siblings, according to the largest cohort of patients with the disease that has been compiled to date.

For HLA-matched sibling transplants, 5- and 10-year survival probabilities were both 62%, whereas the combined average survival probability for HLA-mismatched relative donors, HLA-matched unrelated donors, and HLA-unmatched unrelated donors was 42% after 5 years and 39% after 10 years, Dr. Paul J. Orchard of the University of Minnesota, Minneapolis, and his colleagues reported.

Of surviving patients, 70% have visual impairment and 10% have auditory impairment and motor delay. Despite this, most survivors are attending a public or specialized school, and 65% of survivors reported performance scores of 90 or 100 at last contact, the investigators said.

Graft failure was the most common cause of death, occurring in 50% of HLA-matched sibling transplant patients and in 43% of alternative HLA transplant patients. Veno-occlusive disease and interstitial pneumonitis rates were also high, both at about 20%.

“There is an urgent need to improve engraftment by developing novel strategies that target the microenvironment and study the association between genetic variants of osteopetrosis and transplantation outcomes,” the researchers said.

Find the full article in the July 9 issue of Blood (Blood 2015;126:270-6).