After bone marrow transplants, many patients battle complications from the treatment of their cancer and suffer from illnesses that overwhelm their compromised immune systems.
Dr. Danielle Zerr visits Jordan Keen four days after his stem cell transplant to fight acute lymphocytic leukemia.
One common illness is a viral infection that attacks the central nervous system and can cause delirium, seizures and even encephalitis (an inflammation of the brain).
The mortality rate among those developing encephalitis is relatively high, and those who survive often suffer long-term neurological problems, including loss of memory and concentration, that can continue throughout their lives.
Dr. Danielle Zerr, an infectious diseases expert and medical director of infection control at Children's, is leading a team that seeks to better understand the origin of these viral infections.
The team's focus is HHV-6, a common herpes virus thought to be present in more than 95% of the human population. People are usually infected with HHV-6 by age 2; most cases typically run their course, requiring only rest and comfort measures for fever.
However, in people who are immunocompromised, HHV-6 infection can be severe or even fatal.
"Like all herpes viruses, HHV-6 establishes a lifelong infection in the host, but usually remains dormant.
"We're trying to figure out how often HHV-6 reactivation is responsible for these devastating viral infections after stem cell transplant so we can determine if the burden of the disease warrants an early intervention with an antiviral medication," explains Dr. Zerr.
"If we are to make a difference with this virus, we will need to treat early, before patients become very sick.
"Almost half of all bone marrow transplant patients develop active HHV-6 infections, so we potentially are talking about treating a lot of patients to prevent serious illness in a few.
"That's why we need a better understanding of how much disease this virus is causing before we use medications that have side effects in this fragile population."