Adventures in Biomarkers
You may have heard a lot of buzz about biomarkers these days. To recap a biomarker is an objective, quantifiable characteristic of a biological process.1 Asthmatics can think of these as some of the “tests” that they may already be participating in. Ones that you may be familiar with are testing for eosinophils either (blood or sputum), exhaled nitric oxide (FeNO), periostin and IgE. These biomarkers are related to different components of asthma and how they are related to understanding disease mechanism and treatment options or areas of development.
What has been your experience with biomarkers? Has your doctor expressly said that you were being tested for a biomarker? How have they phrased this to you? I would presume that most of us have had experience with blood testing for biomarkers, have you had experience with nitric oxide testing or sputum testing? I have had the pleasure of being tested for most of these, I am part of a clinical center that is very excited about sputum. So I have had a lot of sputum testing. My eosinophils are mostly monitored by sputum.
I was delighted to learn that there are new developments in biomarkers that are aligning with the type of asthmatic responses. Asthmatics responses include the phases of early, late, and dual phases.
A quick recap on the phases
These are asthma symptoms that occur after allergen exposure in allergic asthma. Early phases occur quickly after allergen exposure, after 15-30 minutes and generally subside quickly. If it occurs with a delayed reaction that typically occurs 3-4 hours after exposure it can be considered a dual response.4 Late phases responses are thought to be associated with bronchial hyperresponsiveness, this lowers the threshold for the airway to be able to handle allergen exposure and may increase thresholds. These are thought to be a result of an inflammatory reaction.
A recent study that examined genes in sputum versus those that are identified in blood assay, set out to identify the sensitivity between blood markers and sputum markers in identifying dual responders from early respondents. The study identified 41 genes that were differentially expressed at seven hours post challenge, in comparison to those identified at baseline. This has helped to identify the unique differences in genes that are expressed in the phases. It is thought that this information will be able to help identify more characteristics in asthma phenotypes.4 The more we can learn about phenotypes, the more personalized our treatment can be.
Do you get muscle cramps caused by your asthma medicine?