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Saliva reliable in measuring CRP, PCT and NE in patients with COPD

Saliva may be a viable bio-sample in monitoring patients with COPD and exacerbation management, according to study results.

“As disease management shifts increasingly toward point-of-care, there is urgency to develop easier, less stressful sampling methods especially for monitoring chronic conditions,” Neil Patel, MD, of the department of respiratory medicine at University Hospitals of North Midlands in the United Kingdom, and colleagues wrote. “Whilst a validated [C-reactive protein (CRP)] saliva-based assay is available, we have also demonstrated that modifications of existing body-fluid assays provides reproducible results for saliva.”

From January 2010 to March 2012, Patel and colleagues measured the salivary CRP, procalcitonin (PCT) and neutrophil elastase (NE) in 143 participants to determine whether these levels could be measured in unstimulated whole saliva, and to explore differences between patients with COPD and controls with normal lung function.

The participants included 20 non-smokers and 25 smokers with normal spirometry, as well as 98 patients with COPD.

The researchers monitored participants during three visits over 14 days. At each visit, the researchers recorded Medical Research Council dyspnea score and performed spirometry and collected unstimulated whole saliva.

Participants completed a daily self-assessment diary including scores on breathing, activities of daily living, sputum features and cough presence.

Salivary CRP differed between the groups, with increases in the COPD group (median = 1.66 ng/mL) compared with non-smokers (median = 0.89 ng/mL) but not those who smoked (median = 1.7 ng/mL).

Smokers had an elevated salivary PCT (0.13 ng/mL) compared with non-smokers (0.09 ng/mL) and patients with COPD (0.09 ng/mL).

Smokers also had raised NE levels (408 ng/mL) when compared with non-smokers (152 ng/mL) and patients with COPD (189 ng/mL).

Each biomarker increased during COPD exacerbations. Levels of CRP increased by 5.74 ng/mL, PCT increased by 0.38 ng/mL and NE increased by 539 ng/mL; alongside a reduction in forced expiratory volume in 1 second (P < .001) and patient-recorded activity of daily living (P < .014) and breathing scores (P < .006).

“Whilst salivary CRP — or any other analytes — may not be sufficiently sensitive for evaluating COPD risk and outcome, it could serve as a potential surrogate for determining exacerbation onset,” the researchers wrote. – by Ryan McDonald

Disclosure: The researchers report no relevant financial disclosures.