Gene therapy corrects immune-system disease

London - A team of international scientists has used gene therapy to successfully treat two patients with a rare but deadly disease of the immune system, marking a small but significant step in the push toward DNA-based medicine.

In a study published in the journal Nature Medicine, researchers described how they introduced a corrective gene to undo the damage caused by a form of chronic granulomatous disease, or CGD. The rare affliction, which is more commonly inherited by men, makes patients extremely vulnerable to infections.

In the latest gene-therapy experiment, two adult men with CGD were treated with gene therapy for 1-1/2 years. Each of the two patients had inherited a defective gene that makes it difficult for their bodies to produce a particular enzyme. As a result, their myeloid cells, a form of white blood cell, can't mount the appropriate response against fungal or bacterial infection.

To fix the problem, researchers used a virus to ferry corrective genes for the enzyme into the patients. The appropriate genes got switched on. But in a surprise to the scientists, the gene-corrected blood cells also tripled in number, improving the performance of the therapy.

The experiment is one of the first to show that gene therapy can successfully treat diseases of the myeloid system. Scientists refrain from pronouncing their achievement a cure, until they verify that the effects last over time.

Source: Gautam Naik in "The Telegraph"