Cystic Fibrosis

Researchers hoped that by discovering of the gene responsible for CF, a genetic approach to curing the disease will be developed. In gene therapy, a normal gene is inserted into cells to replace the defective gene. In most gene therapy experiments, cells from an affected organ are removed from the body and infected with a virus that has been modified to carry the normal gene. The newly infected cells are then put back into the body. In CF, this method has not yet been successful. The primary reason is that the lungs are equipped with a complex barrier, preventing successful penetration and delivery of the normal gene.

In 1994, researchers successfully transferred a virus containing the normal CFTR gene into four CF patients. The patients inhaled the virus into the nasal passages and lungs. An adenovirus, the virus used to carry the gene, is considered to be relatively safe but can cause several undesirable side effects. Nevertheless, one patient in this experiment developed side effects including headache, fatigue, and fever. It is unclear whether the experiment improved mucus clearance in the lungs or if the corrected gene produced adequate amounts of the corrected protein.

Before gene therapy can be considered, researchers must overcome several obstacles. The most important obstacle is the use of viruses as carriers for the normal genes. Some scientists feel that viruses are too dangerous, especially for patients who already have a chronic disease. Current studies are underway to investigate the use of liposomes, or small microscopic spheres consisting of a fatty-substance called a lipid, to transport the corrected gene.