Related Hematopoietic Stem Cell Transplantation (HSCT) for Genetic Diseases of Blood Cells

Many genetic diseases of lymphohematopoietic cells (such as sickle cell anemia, thalassemia, Diamond-Blackfan anemia, Combined Immune Deficiency (CID), Wiskott-Aldrich syndrome, chronic granulomatous disease, X-linked lymphoproliferative disease, and metabolic diseases affecting hematopoiesis) are sublethal diseases caused by mutations that adversely affect the development or function of different types of blood cells. Although pathophysiologically diverse, these genetic diseases share a similar clinical course of significant progressive morbidity, overall poor quality of life, and ultimate death from complications of the disease or its palliative treatment. Supportive care for these diseases includes chronic transfusion, iron chelation, and surgery (splenectomy or cholecystectomy) for the hemoglobinopathies; prophylactic antibiotics, intravenous immunoglobulin, and immunomodulator therapies for the immune deficiencies; and enzyme replacement injections and dietary restriction for some of the metabolic diseases. The suboptimal results of such supportive care measures have led to efforts to implement more aggressive therapeutic interventions to cure these lymphohematopoietic diseases. The most logical strategies for cure of these diseases have been either replacement of the patient's own hematopoietic stem cells (HSC) with those derived from a normal donor allogeneic bone marrow transplant (BMT) or hematopoietic stem cell transplant (HSCT), or to genetically modify the patient's own stem cells to replace the defective gene (gene therapy).