Soluble CD163 Levels and CD163? Monocyte/Macrophage Counts in Patients with Asthma

CD163-expressing macrophages are involved in the inflammatory response in asthma. To assess sputum and serum soluble CD163 (sCD163) and cytokine levels in patients with asthma. Further discussed was the difference between sCD163 and other classic inflammatory mediators. Sputum was successfully induced in asthma patients (n=85) and healthy controls (n=21). Interleukin (IL)-4, IL-5, IL-1β, IL-8, IL-9, IL-6, and sCD163 levels in sputum were measured. CD163+ monocytes in blood were evaluated using flow cytometry. Sputum sCD163 level significantly increased in asthma (median: 22.4 pg/ml; IQR, 11.52-42.91), unlike healthy controls (10.54 pg/ml;9.85-23.5; P<0.001). Sputum sCD163 (P=0.020) and serum sCD163 (P=0.032) levels were significantly higher in patients with severe asthma compared to those with mild/moderate asthma. Percentage of CD163+ monocytes in patients with asthma was significantly lower than the controls (P<0.001). Increased sCD163 levels in sputum are associated with the impairment of lung function.