As a part of their study, the researchers evaluated serum levels of YKL-40 in 253 adults patients in three asthma and control groups at Yale, the University of Wisconsin, and the University of Paris.
They conducted simple blood tests and found that patients with asthma had increased circulating serum levels of the protein YKL-40.
"The results demonstrate that YKL-40 is significantly elevated in severe asthma," said Geoffrey Chupp, M.D., associate professor of medicine at Yale and the lead author on the study.
"Having a blood test to characterize asthmatics will be useful in pursuing asthma research and potentially in managing asthma."
Jack Elias, M.D., professor and chair of medicine, professor of immunobiology, and senior author of the study, said the findings are among the first to define a parameter for asthma that can be assessed with a blood test.
"This may allow us to identify a subpopulation of patients with severe asthma and give us insights into the biologic processes that make the disease so severe in these individuals," Elias said.
"Our studies also have demonstrated that eliminating YKL-40 decreases specific types of tissue inflammation—which could be of particular benefit to asthmatic patients with an elevated level of this protein."
The scientists are now calling for research on the biology of YKL-40 to be incorporated into investigations on the pathogenesis of asthma, as well as additional studies needed to define the potential role of a YKL-40 blood test in asthma management.
The study appears in the New England Journal of Medicine.