Hemopexin was an effective biomarker protein capable of diagnosing chronic obstructive pulmonary disease (COPD) and differentiating COPD from asthma, according to study results published in Allergy, Asthma & Immunology Research.
The study included Australian patients with COPD (n=141), severe asthma (n=127), mild or moderate asthma (n=54), and individuals who were considered “nonrespiratory controls” (n=71). Using immunoassay methods, the investigators measured the validation biomarker levels in the sera of patients with disease as well as nonrespiratory disease control individuals. All markers were assessed individually and in combination for the purpose of disease differentiation. The markers were then compared with established biomarkers, including C-reactive protein (CRP), interleukin-6 (IL-6), and white blood cell (WBC)/blood eosinophil count.
All participants with either COPD or asthma had higher WBC count, peripheral blood eosinophil counts, as well as higher CRP and IL-6 when compared with control individuals. There were significant differences between the disease groups and systemic inflammatory phenotypes in terms of ceruloplasmin, haptoglobin, and hemopexin levels (P =.0001 for all).
In a comparison between patients with COPD and control individuals, hemopexin demonstrated the best performance as an individual biomarker that could diagnose COPD (area under the curve [AUC], 98.3%; 95% CI, 96.7%-99.9%). Additionally, hemopexin was capable of effectively differentiating COPD from asthma (AUC, 97.0%; 95% CI, 95.4%-98.6%).
The investigators suggest their findings indicate hemopexin can outperform other established biomarkers. Likewise, a combinatorial marker analysis of a panel that included hemopexin, haptoglobin, and other established biomarkers offered the highest AUC for the diagnosis of asthma (AUC, 87.5%; 95% CI, 82.8%-92.2%) and performed better than the use of only haptoglobin (P ≤.01).
Limitations of the study included its single-center design and its cross-sectional nature, which the investigators suggest limited the ability to determine the longitudinal stability of the markers.
The investigators “propose an anti-inflammatory axis between the airways and systemic circulation, in which hemopexin is a protective component in airway disease.”
Winter NA, Gibson PG, Fricker M, Simpson JL, Wark PA, McDonald VM. Hemopexin: a novel anti-inflammatory marker for distinguishing COPD from asthma. Allergy Asthma Immunol Res. 2021;13(3):450-467. doi:10.4168/aair.2021.13.3.450