Researchers at Washington University School of Medicine in St. Louis said the immune response is activated in patients with severe asthma and COPD -- chronic obstructive pulmonary disease.

"We've cracked the first part of the molecular code that links a viral infection to the later development of chronic inflammatory diseases like asthma and COPD," said senior author Dr. Michael Holtzman, a professor of medicine and a pulmonary specialist at Barnes-Jewish Hospital. "With this information, we can more precisely diagnose and monitor these types of diseases and then better target our treatment to specific abnormalities. That's a big step forward from simply monitoring breathing status."

The findings are reported in the online edition of the journal Nature Medicine.