Lung Function Not Impaired After Cell Transplant in Adults with SCD

Lower intensity conditioning before hematopoietic stem cell transplant (HCT) maintained measures of lung function and even improved others in adults with sickle cell disease (SCD), according to findings published in the Annals of the American Thoracic Society.

Lung injury and diminished lung function are common complications of SCD. While cell transplant is considered curative, many adults are unable to tolerate harsh chemotherapy regimens necessary to prepare the body for HCT. The investigators examined lung function following lower intensity treatment to determine if transplant worsens lung injury and function.

“By using a low-intensity blood stem cell transplant for sickle cell disease, we may be able to stop the cycle of lung injury and prevent continued damage,” study lead Parker Ruhl, MD, said in a press release from the National Institutes of Health (NIH). “Without the ongoing injury, it’s possible that healing of lung tissue might occur, and this finding should help reassure adults living with sickle cell disease who are considering whether to have a low-intensity stem cell transplant procedure that their lung health will not be compromised by the transplant.” Ruhl is an associate research physician and pulmonologist at NIH.

The researchers followed 97 patients with SCD who underwent a non-myeloablative HCT between 2004-19 at the NIH’s Clinical Center. The patients in the prospective cohort were followed for up to three years. Lung function tests performed before and after transplant included forced expiratory volume in one second (FEV-1) lung diffusing capacity, which measures how much oxygen moves from the lungs to the blood on exhalation. The researchers also had patients perform a 6-minute walking distance test.

FEV-1 levels were generally unchanged after transplant compared with pre-transplant, providing an indication that lung function did not worsen over time. Median pre-transplant FEV-1 was 68.3% of the expected volume for age and gender. Three years after transplant, the median FEV-1 was 69.2%

In addition, lung diffusing capacity (DL_CO) significantly increased by 3.7%. Overall, patients improved their 6-minute walking test distance by 25.9 m.

This study was funded in part by supported in part by the National Institute of Allergy and Infectious Diseases and the National Heart, Lung and Blood Institute.