Human rhinovirus, the most prevalent virus associated with the common cold, can cause pneumonia in bone marrow transplant patients, new research shows.
The study “Human Rhinovirus Detection In The Lower Respiratory Tract Of Hematopoietic Cell Transplant Recipients: Association With Mortality” was published in the journal Haematologica.
Bone marrow transplant patients have compromised immune defenses due to their disease and the immunosuppressant treatment they undergo before receiving healthy donor cells. As a result, these patients are particularly susceptible to infections, including in the respiratory tract.
Rhinovirus, the most common respiratory virus detected in these patients and present year-round, has been overlooked traditionally. Importantly, current evidence of the rhinovirus’ presence in these patients takes advantage of better viral detection methods developed over the past decade.
“This is such a prevalent virus … about 25 percent of stem cell transplant patients get infected [with rhinovirus] during the first year”, Michael Boeckh, MD, the study’s lead author said in a press release. Boeckh also is Head of the Infectious Disease Sciences Program at Fred Hutchinson Cancer Research Center. “The virus was always considered kind of a common cold, a mild virus. People shrugged their shoulders, what should we do about it, it comes and goes.”
The study included 697 patients transplanted between 1993 and 2015 who had tested positive for rhinovirus in respiratory samples. These patients were compared with 273 patients with lower respiratory tract infections caused by seasonal viruses – respiratory syncytial virus (RSV), parainfluenza virus, or influenza, which already are known to induce pneumonia.
Researchers found that rhinovirus caused pneumonia less often than the other viruses. About 15% of transplant patients infected with rhinovirus and showing symptoms of upper tract respiratory infection – “common cold” – developed lower respiratory tract infections or pneumonia. This was approximately half the frequency of patients infected with RSV. However, rhinovirus induced similar mortality (about 40%) in comparison with the other viruses.
The team also showed that low monocyte (a type of white blood cell) count and high steroid use (drugs that prevent graft-vs.-host disease in transplant patients) were risk factors associated with mortality among patients with lower respiratory tract infection.
“In summary, transplant recipients with rhinovirus detection in the lower respiratory tract had high mortality rates comparable to viral pneumonia associated with other well-established respiratory viruses. Our data suggest rhinovirus can contribute to severe pulmonary disease in immunocompromised hosts,” the team wrote.
Overall, the results highlighted the need to adopt efficient infection prevention measures and to develop antiviral drugs for common cold-associated viruses.
“For a company or anybody to step forward and say, ‘I’m going to make this a priority,’ you have to show that there’s a real disease,” said Boeckh.
Current research addresses why rhinovirus is so dangerous to transplant patients. Work led by Alpana Waghmare, MD, one of the study’s co-authors and assistant professor of pediatrics at the University of Washington, is evaluating which patients are most likely to develop pneumonia from rhinovirus. Future plans include studying whether certain patients are at greater risk of developing infection, and if there are other risk factors for pneumonia from infection with rhinovirus.
“So many of our patients get rhinovirus, but most of the infections are mild and we want to know who would likely benefit from any potential therapies” said Waghmare.
In the absence of effective therapies, Waghmare advises patients who are within the first year of receiving a transplant to immediately check with their doctor if they develop cold-like symptoms. Furthermore, these patients should avoid contact with family members and friends with cold or flu symptoms.