Cytomegalovirus May Speed Disease Progression in Cystic Fibrosis

Researchers have identified a potential explanation for why some patients with cystic fibrosis experience faster disease progression, finding that patients with cytomegalovirus had earlier times to lung transplant referral and reaching final stages of disease.

Cytomegalovirus, which is typically considered harmless, is a type of herpes virus often contracted during late adolescence and early adulthood and is estimated to be prevalent in over 90% of people aged 80. The virus is most notable for causing visceral disease in immune-suppressed patients, as well as congenital infections. Recently, a growing body of researcher has indicated that the virus is associated with several chronic conditions such as heart disease and dementia; however, to date, no studies have examined the association between the virus and deterioration in chronic respiratory disease.

"Cytomegalovirus is normally dormant in people who have it, but it can become active again and spread more quickly after infection with other bacteria," Michael Parkins, associate professor of medicine, Microbiology and Infectious Diseases, University of Calgary, Canada, said in a statement. "We know that cystic fibrosis patients are more likely to develop lung infections, so it's possible that repeated cycles of activation of the virus exaggerates the damage to patients' lungs, contributing to faster disease progression."

The study included 56 patients referred for lung transplant at the Calgary Adult Cystic Fibrosis Clinic between 1991 and 2017, of which 30 (54.6%) tested positive for cytomegalovirus.

These patients were referred for lung transplants approximately 8 years earlier compared with patients without the virus and died an average of 10 years earlier than uninfected patients. The researchers also looked at patients’ sex, body mass index, education, and presence of other infections and genetic traits, determining that cytomegalovirus was the most significant factor in disease progression.

“The association we found does not necessarily mean that cytomegalovirus directly causes more rapid disease progression—further studies are needed before such a bold statement could be made,” Parkins said “However, our findings provide the first indication that this virus may have an impact on progression of cystic fibrosis, potentially leading to earlier transplant referral and even death.”

The researchers also noted that the study is limited to a small number of patients with a lack of information regarding the direct cause of death or transplantation.

Currently, there are several cytomegalovirus vaccines being studied in other areas of medicine, which could be examined among patients with cystic fibrosis as a possible prevention method.

According to Parkins, there are also several interventions that could be assessed as management strategies for patients with cystic fibrosis that have the virus. He said: “Treatment might involve regular medication to slow the spread of the virus. Alternatively, treatment could be given only during times of reactivation, for example, following injection of symptom flare-ups.”

Reference:

Parkins M, Ramos K, Goss C, Somayaji R. Cytomegalovirus—an unrecognised potential contributor to cystic fibrosis disease [published online April 7, 2019]. Eur Respir J. doi: 10.1183/13993003.01727-2018.