Washington, January 18 : Scientists have made a significant ascent towards the goal of personalizing asthma therapy by identifying different subtypes of the disease, which are based on distinct protein profiles.
Researchers at the University of Texas Medical Branch at Galveston (UTMB) and their colleagues elsewhere made this advance with the help of state-of-the-art protein screening techniques, which they applied to samples taken from 84 asthmatic volunteers.
They have revealed that one of the profiles corresponds to a variety of severe, treatment-resistant asthma which, though rare, is responsible for 40 to 50 per cent of the total health care costs associated with the disease.
"We know that in asthma some people respond to very specific types of therapies and others don't," said Dr. Allan Brasier, director of UTMB's Sealy Center for Molecular Medicine.
"Being able to discover different asthma subtypes should allow us to tailor our treatments to increase the odds of a positive response," he added.
Brasier, who is also a senior author of a paper on the study appearing in the Journal of Allergy and Clinical Immunology, writes that the research team squirted a small amount of saline solution through tiny tubes into the anaesthetized volunteers' lungs and, then, sucked the solution back out.
This way, the saline solution brought with it proteins washed free from walls of the network of air passages and sacs in the lungs.
"In each sample, we measured 25 different cytokines, inflammatory signaling proteins that play a very important role in asthma. We found that our samples fell into one group associated with severe asthma, another group that looks like it represents less severe disease, and two additional groups whose significance we don't yet understand," Brasier said.
According to him, the unknown protein profiles could be produced by types of asthma that respond differently to treatment, or that are generated by different genetic or environmental sources.
The study's authors write that these and other hitherto undiscovered protein patterns may eventually be used to diagnose types of asthma aggravated by cigarette smoke, or that cause a steady decline in lung function over a number of years.
"Until now, all we knew was that asthma was a disease that manifested itself in many different ways. By using these patterns of multiple different proteins, we can start defining those different subtypes much more accurately - which is very useful for trying to identify which ones will respond to which treatments," Brasier said.
He made it clear that clinical applications of asthma protein profiling would have to await the discovery of additional protein patterns to match with other subtypes of asthma, and for more sensitive tests that would allow for less invasive sampling techniques.
"We're still a little bit away from treating people, but that's coming. This is the proof of principle that you can apply proteomic patterns to personalized medicine in asthma," Brasier said.