Investigation of U.S. gene therapy death focuses on fungal infection

A virus used in a gene therapy experiment likely did not cause the death of a woman suffering from rheumatoid arthritis, although it cannot be completely ruled out, U.S. government health advisers said today.

Advisers to the National Institutes of Health said that a massive fungal infection is near the top of the list of likely culprits in the death of Jolee Mohr.

Mohr, 36, died at University of Chicago Medical Center on July 24, several weeks after receiving the second injection of trillions of genetically altered viruses as part of a gene therapy study for rheumatoid arthritis.

Doctors have since struggled to determine how she died, though a massive Histoplasma capsulatum infection appears to be a leading cause. Advisers to the National Institutes of Health met Monday to hear autopsy results and other evidence to determine what role _ if any _ the injected virus also may have played.

The genetically engineered virus was used as a vector or vehicle to carry a new gene into Mohr's body, helping it to make a protein that would ease her arthritis pain. Mohr had suffered from arthritis since her 20s.

"We can't to 100 percent certainty exclude the vector but as was presented, the data would suggest that it's unlikely to be playing a role," said Dr. Howard Federoff of Georgetown University Medical Center, chairman of the Recombinant DNA Advisory Committee. Federoff said the fungal infection, called histoplasmosis, was "near the top" of the lists of likely causes for Mohr's death.

The fungus is commonly found in the Midwest. At the time of her death, Mohr was taking drugs that suppressed her immune system, which would have weakened her body's ability to fend off an infection.

It will take several weeks to complete tests that would show if any of the injected viruses migrated beyond Mohr's right knee. If none is found, that would make it even less likely the virus played a role.