Serum high-sensitivity C-reactive protein can be an airway inflammation predictor in bronchial asthma

It is controversial that the serum high-sensitivity C-reactive protein (hs-CRP) can be a useful marker of airway inflammation in bronchial asthma, because various factors have been reported to affect hs-CRP levels. We conducted a study in patients with mild bronchial asthma without complications to determine whether hs-CRP is a useful indicator of airway inflammation. The induced sputum cell differentiation, respiratory function tests, bronchial hyperresponsiveness tests, and hs-CRP measurement were performed in the subject population consisted of 40 healthy volunteers and 45 patients with bronchial asthma. The log-transformed (log) serum hs-CRP level was higher in asthmatic patients compared with healthy controls (2.49 ± 0.41 versus 2.21 ± 0.39; p = 0.002). A receiver-operating characteristic (ROC) analysis showed a sensitivity of 0.69 and specificity of 0.70 for a log serum hs-CPR of 2.3 to distinguish asthmatic patents from healthy controls. The log serum hs-CRP level negatively correlated with forced volume in 1 second (FEV1.0)%pred (r = -0.31, p = 0.04), positively correlated with sputum eosinophils (r = 0.34, p = 0.02), negatively correlated with sputum macrophages (r = -0.56, p < 0.001), and did not correlate with log 20% fall in FEV1.0 (PC20) (r = -0.09, p = 0.56). A multiple regression analysis revealed that the log serum hs-CRP concentration significantly correlated with eosinophils (p = 0.019) and neutrophils (p = 0.042) in the sputum, respectively. Serum hs-CRP may be a useful marker of airway inflammation in nonsmoking asthmatic patients without complications, such as heart disease, hypertension, hyperlipidemia, chronic obstructive pulmonary disease, or infection.