Sickle Cell Disease: A Cure on the Horizon ~ Dr.AZ

[sdanyaro]

Sickle Cell Disease: A Cure on the Horizon
by
Abba Zubair MD PhD.
Clinical Instructor,
Harvard medical School,
Joint Program In Transfusion Medicine,
Dana-Farber Cancer Institute,
Brigham and Women's Hospital.
Boston, Mass

Sickle Cell Disease (SCD) is a genetic disease that affects red blood cells (RBC). Because the RBCs form a sickle shaped pattern, the disease is called Sickle Cell Disease. The principal symptom of the disease is anemia (lack of RBC) and therefore the disease is sometimes called Sickle Cell Anemia. The cells that make blood red (RBC) are red because they have a chemical called Hemoglobin (Hb). This chemical carries oxygen (carbon dioxide and nitric oxide) from the lungs to the tissue for energy production. The Hb (HbS) in SCD patient is almost identical to normal individuals except in one amino acid (basic elements that make up proteins). This change makes HbS insoluble in low oxygen conditions such as infection, low temperature and exercise. In such conditions, the HbS precipitate in the RBCs and makes it more rigid and sickle shaped. As a result, these rigid RBCs have shortened life span and block small vessels especially in the lungs and the brain with devastating consequences.

Two identical genes are available to code every protein in a living cell; one inherited from mother and the other from father. In the case of SCD, the genes that code for globin, a part of hemoglobin, are changed. Only individuals with both globin genes affect have the disease, while those with only one gene affected are called carriers and are almost normal. Therefore, the disease is said to be autosomal recessive. If one of the parents is a carrier and the other is normal, there is a zero chance that their offspring will have the disease but there is 1 in 2 chance their offspring will be a carrier. If both patents are carriers, there is 1 in 4 chance that their offspring will be affected. If one of the parents has the disease and the other is a carrier, there is 1 in 2 chance their offspring will be have the disease or be a carrier. If both parents have the disease, there is almost a 100% chance that their offspring will have the SCD. The last scenario was very unlikely until recently because most patients die young. However, with improved medical care and higher standard of living, patients with SCD have near normal life span.

Until recently there is no definitive cure for SCD because it is a genetic disease. Clinical investigators started to apply bone marrow (stem cell) transplant, a treatment that has long been used to treat cancer patients, to treat SCD patients and other patients with hemoglobinopathies (group of diseases that affect hemoglobin function or structure e.g. thalassemia, SCD etc.).

Stem cell transplantation is a treatment that can cure sickle cell anemia and thalassemia major. In this procedure, abnormal marrow can be replaced with normal bone marrow through the use of high-dose chemotherapy with radiation in order to allow stem cells donated from a genetically matched donor to be accepted by the patient's bone marrow. Although this type of treatment can cure some patients with sickle cell anemia or thalassemia, the side effects related to this treatment could be severe and even life threatening.

We have recently opened a phase II study in which we offer an experimental treatment program that uses reduced-dose chemotherapy with stem cell transplantation for treatment of sickle cell anemia and thalassemia. The purpose of this study is to determine if this lower dose, safer treatment, will still let donor cells to be accepted by your body. If the donor stem cells can become even a fraction of the cells that are accepted by your bone marrow, we expect at least partial correction of your red blood cell disorder. This type of treatment differs from traditional stem cell transplantation in three major ways. First, no radiation therapy is administered. Second, the drugs which are used here are not the same drugs that we use in standard transplant. Third, they are given here in lower doses than would be given for a standard transplant. Because of these factors, we expect this modified, reduced-dose chemotherapy regimen to be safer and to generate fewer side effects than the usual high-dose treatment.

On this study, patients will be monitored for the percent of donor cells that are accepted by the patient's bone marrow, as well as the clinical condition of the patients. This study is open at Dana-Farber Cancer Institute, Brigham and Women's Hospital and the Massachusetts General Hospital. We expect to enroll twenty patients. Two Nigerians have already been enrolled into the study with very encouraging results. Individuals interested in the study can contact Dr. Catherine Wu  cwu@partners.org.

[Anonymous]

sdanyaro I definitely think just like you.