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Immune Deficiency Diseases
Researchers have been studying stem cells in bone marrow for over ten years and are studying effective methods for stem cell transplants for patients with immune deficiency diseases. The purpose of bone marrow transplantation is to give the patient with an immune deficiency disease a new source of bone marrow stem cells. Stem cells are known for their ability to develop into all type of blood cells including T cells and B cells which produce antibodies. One group of researchers have been concentrating on an immune deficiency disease called chronic granulomatous disease (CGD) in which there is a defect in an enzyme called phox which is needed by white blood cells to generate hydrogen peroxide which the cells need to kill bacteria and fungi. This disease leads to frequent and often life-threatening infections. Researchers have removed stem cells from patients with CGD. They then inserted the correct form of the phox gene into the stem cells and then transfused the corrected stem cells back into the patient. They then sampled the patient's blood to see if the stem cells were producing white blood cells with the functional phox gene. They were able to detect phox activity in white blood cells for an average of 3 months after the gene-corrected stem cells were transfused. The study demonstrates that gene therapy of stem cells can produce functionally normal blood cells in patients for a prolonged period. The most effective treatment for another immune deficiency disease disorder called SCID (Severe Combined Immunodeficiency) is hematopoietic stem cell transplant. Blood forming stem cells found primarily in the bone marrow are introduced into the body in hopes these new cells will rebuild the immune system. It is hoped that one day hematopoietic stem cell transplant will be used to treat AIDS. The power of adult stem cells is tangible and real - in Los Angeles three boys with congenitally impaired immune systems were cured after implantation of adult stem cells.
Immune deficiency diseases occur when part of the immune system is either absent or its function is hampered. An immune deficiency disease can be caused by an inborn defect in the cells of the immune system (called a primary immune deficiency disease) or an extrinsic environmental factor may damage the immune system (called a secondary immune deficiency disease). There are nearly 100 primary immune deficiency diseases and they may differ from one another in many ways, but they all result from a defect in one of the functions of a normal immune system. Primary immune deficiency diseases can occur at any age although the original descriptions of these diseases were in children and they may not present themselves until adult life. DiGeorge's Syndrome which is characterized by the lack of a thymus is one example of a primary immune deficiency disease. Second immune deficiency diseases can be caused by irradiation, chemotherapy, burns and malnutrition. AIDS is an example of a secondary immune deficiency disease caused by the HIV virus.
Because one of the primary functions of a normal immune system is to protect against infections, patients with immune deficiency diseases have an increased susceptibility to recurrent infections such as bacterial and fungal. These infections can be located in the sinuses, bronchi, lungs, or the intestinal tract. Another problem for patients with immune deficiency diseases is the inability of the immune system to differentiate between the body's self and foreign materials. This causes an increased susceptibility to infections when the patient's own immune system attacks their own cells or tissues as if they were foreign.
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