Neutrophil CD11b and soluble ICAM-1 and E-selectin in community acquired pneumonia

It was hypothesized that there would be an upregulation of systemic neutrophil CD11b expression in pneumonia. Expression of CD11b and concentrations of soluble intercellular adhesion molecule (ICAM)-1 and E-selectin were evaluated as potential surrogate markers of the severity of pneumonia. Possible age-related immunosenescence in relation to neutrophil CD11b expression in elderly patients with pneumonia was examined for. In patients with community-acquired pneumonia (n = 36) neutrophil CD11b expression was measured by flow cytometry and soluble ICAM-1 and E-selectin concentrations by enzyme-linked immunosorbent assay. An upregulation of neutrophil CD11b expression and increased soluble adhesion molecule concentrations on admission were confirmed, but the concentrations did not correlate with patient Acute Physiology and Chronic Health Evaluation II scores. Neutrophil CD11b expression was similar between elderly (age range 70-100 yrs) and younger (age range 18-70 yrs) patients with pneumonia. In conclusion, there is evidence of neutrophil and endothelial cell activation in pneumonia as indicated by upregulation of CD11b and increased soluble intercellular adhesion molecule and E-selectin, however, they do not appear to be good surrogate markers of severity of infection. Advanced age does not influence adhesion molecule expression in pneumonia.