Gene therapy for sickle cell disease

A new gene therapy developed by researchers corrects sickle cell abnormalities in mice. The approach, which uses a virus to deliver an "anti-sickling" gene, represents an important first step towards a cure for the disease in humans. Sickle cell disease, also called sickle cell anaemia, is a hereditary disease that causes red blood cells to become sickle-shaped, which makes it difficult for the cells to pass through the bloodstream to deliver oxygen to the body's tissues. This disease is quite common in people of Indian, African and Middle Eastern descent. People with sickle cell disease have two defective copies of a gene for haemoglobin, an oxygen-carrying protein in the blood. The mutation, which occurs in a gene called beta-globin, was discovered earlier, but developing gene therapy for the disease has been quite difficult. This research was carried out at the Massachusetts Institute of Technology. They successfully used a virus to transport an anti-sickling gene into mice with illnesses that mimic sickle cell disease. These researchers first used radiation to wipe out the bone marrow of the mice. Then they gave mice new bone marrow that had been treated with a virus that carried the anti-sickling gene. Gene therapy led to dramatic improvements in the sickle cell disease in mice. It led to an eightfold drop in the number of abnormally shaped cells in one model and sickle-shaped cells completely disappeared after treatment in the other version of the disease. Gene therapy also relieved other symptoms of sickle cell disease, including spleen enlargement, urinary problems and dehydration of red blood cells. The research is an important step toward human clinical trials. The process for producing the virus used in the gene therapy needs to be refined before it is ready for large-scale use. The approach needs to undergo more extensive laboratory and animal testing before it can be tried in humans, but offers a hope of cure for the affected people.

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