A study conducted at the National Institutes of Health (NIH) has found that low-intensity blood stem cell transplants, which utilize less aggressive conditioning methods compared to standard procedures, may not harm the lungs and could potentially enhance lung function in some adults with sickle cell disease (SCD).
The research, detailed in the Annals of the American Thoracic Society, provides insights into whether these milder transplants, which are generally better tolerated by adults, contribute to or prevent further lung damage.
Lung damage and impaired lung function are significant complications and major causes of mortality in individuals with sickle cell disease – a severe blood disorder. The study’s findings suggest that low-intensity transplants might help halt ongoing lung injury and support lung tissue recovery.
Dr. Parker Ruhl, the study’s lead author and an associate research physician and pulmonologist at NIH, highlighted that this could offer reassurance to adults considering this type of transplant, as their lung health might not be adversely affected.
Historically, bone marrow and blood stem cell transplants were the sole curative options for sickle cell disease, but their use has been limited among adults due to the high health risks linked with the intense chemotherapy required and the need for a compatible donor, often a sibling.
These procedures involve infusing patients with stem cells from a donor to generate healthy red blood cells, replacing the dysfunctional “sickled” cells that obstruct blood flow and lead to various complications, including severe pain, infections, stroke, and acute chest syndrome.
According to researchers, approximately one-third of sickle cell stem cell transplants are low-intensity. While these are marginally less effective than standard transplants, they are associated with fewer complications and might be more suitable for adults with existing organ damage. The recent study aimed to determine whether these transplants offer additional benefits for patients with compromised lung function.
The research team examined 97 adults with sickle cell disease who underwent low-intensity stem cell transplants at the NIH Clinical Center between 2004 and 2019. They tracked the patients for up to three years, conducting a range of pulmonary function tests, including forced expiratory volume in one second (FEV-1), diffusing capacity of the lungs for carbon monoxide (DLCO), and a six-minute walk test.
The results showed that overall lung function remained stable after three years, with FEV-1 levels largely unchanged. Notably, DLCO levels and performance on the six-minute walk test improved significantly post-transplant.
Dr. Ruhl noted that further research with larger sample sizes, extended follow-up, and data from other clinical centers, including those with standard transplants, is necessary to fully understand these findings. The NIH team plans to continue monitoring the patients and report on outcomes at five and ten years.
In December 2023, the US Food and Drug Administration approved two genetic therapies using patients’ own blood stem cells for treating SCD. The methods from this study may also be applied to assess lung function in new genetic treatments.
As reported by pharmabiz.com, the study received support from the Divisions of Intramural Research at NIH’s National Institute of Allergy and Infectious Diseases and the National Heart, Lung, and Blood Institute.