“There really isn’t an organ in the body that isn’t affected by sickle cell disease.”
This striking comment was made by the Dr. Bertram Lubin, the CEO and President of the Children’s Hospital Oakland Research Institute (CHORI) and a CIRM Board Member.
Yesterday Dr. Lubin visited CIRM headquarters to talk about sickle cell disease (SCD). SCD is a group of inherited disorders caused by unhealthy, sickle-shaped red blood cells. People with SCD have abnormal hemoglobin, an important protein in red blood cells used to transport oxygen from the lungs to organs and tissues throughout the body.
The What, Why and Who of SCD
Genetic mutations in the hemoglobin genes lead to changes in the hemoglobin protein that cause normal, healthy disc-shaped red blood cells to take on a crescent, sickle shape. These sickle cells are a big problem because they stick to each other and to the walls of blood vessels, causing blockage and impeding blood flow. This leads to a plethora of clinical complications that we will touch on later in this blog.
Dr. Lubin shared some shocking facts including that 2 million African Americans are carriers of SCD mutations and 100,000 Americans have the disease. In the US, 1000 babies are born with SCD each year, but this number pales in comparison to the 1000 African babies that are born with SCD each day.
“So anything we do here with CIRM has a direct impact on sickle cell disease,” Lubin explained. “It’s something we should consider because it could have a global impact on SCD.”
SCD Affects Every Organ in the Body
Dr. Lubin next discussed a laundry list of clinical manifestations associated with SCD, making it clear that SCD is not just a blood disorder, it affects every organ and tissue in the body. Examples he gave included infection, enlarged spleen, stroke, bone disease, retinopathy, and gastro-intestinal complications. And these were only a handful of the symptoms he discussed that SCD patients deal with.
However, Dr. Lubin emphasized that early detection of SCD in babies can drastically improve the quality and length of life of SCD patients. He proudly explained how California was the first state to screen every newborn baby for SCD (a procedure that is now done in every state) and that CHORI’s Center for Sickle Cell Disease and Thalassemia is one of the major SCD programs in the world. Their center “strives to improve public awareness of these diseases, expand the current knowledge base, and ultimately, to provide innovative treatment, care – and cures.”
Dr. Lubin also commented on the importance of knowing if patients who go to the ER or doctor have SCD:
“With new born screening before we identified who had sickle cell disease, an African American child could come to the emergency room with a 103 F temperature. And they would say, well this is a virus, go home, and half of those kids would die by the next day. Because those with pneumococcal sepsis [a bacterial infection that SCD patients have an increased risk for] don’t last very long. Now when someone comes into the emergency room with a 103 F temperature and we know they have sickle cell, they get antibiotics right away. That told us there is a different way to do it and that really showed how genetics and public health can have an impact on the overall health of the population.”
Treatments and Hope for SCD
Dr. Lubin ended his talk by discussing the current management and treatment strategies for SCD patients. Early identification through universal newborn screening and family education are essential as well as preventative measures like penicillin and immunization to avoid infection.
As for therapeutic interventions, he mentioned blood transfusions, hydroxyurea treatments (which boosts the levels of healthy hemoglobin in blood cells), and bone marrow stem cell transplants. He said while bone marrow transplants have successfully treated some SCD patients, there are still many barriers to this form of treatment. Only 14% of families of SCD patients have an HLA-identical sibling donor and only 19% have an unrelated HLA-matched donor. Additionally, some doctors avoid recommending bone marrow transplants to SCD patients because of the risks for transplant rejection (graft vs. host disease) and death.
However, Dr. Lubin is hopeful that recent advances in stem cell research and genome engineering will one day make stem cell transplants the go-to treatment for SCD patients.
He ended with:
“The future of curative therapies that will have broad availability for SCD might follow advances in genomic correction of sickle mutation in hematopoietic [bone marrow] stem cells.”