A gender difference in circulating neutrophils in malnourished patients with COPD

Circulating markers of inflammation in chronic obstructive pulmonary disease (COPD) may correlate to disease progression and extrapulmonary complications such as malnourishment. However, surprisingly little is known about gender-related differences for circulating inflammatory markers in COPD.

To characterize differences in circulating markers of inflammation in malnourished female and male patients with COPD.

Thirty female and 11 male patients with a clinical diagnosis of COPD and malnourishment were examined. A group of control subjects without evidence of COPD was recruited for comparison of some variables.

Blood samples were drawn, and the following parameters were studied: leukocytes and differential counts, C-reactive protein (CRP), tumor necrosis factor-α, interleukin (IL)-6 and IL-8, myeloperoxidase (MPO), neutrophil elastase (NE), intracellular adhesion molecule-1, vascular endothelial adhesion molecule-1, and E-selectin.

The mean neutrophil concentration was significantly (P = 0.019) higher in female (4.5 × 10(9)/L) than in male patients with COPD (3.5 × 10(9)/L) and significantly higher than in female control subjects (3.1 × 10(9)/L) (P < 0.01, n = 85). The mean CRP values were considerably higher in female (4.9 mg/mL) than in male patients with COPD (1.5 mg/mL), but the difference was not statistically significant (P = 0.20). The mean concentrations of IL-6 and IL-8 tended to be higher in female than in male patients with COPD, but these differences did not reach statistical significance either (P > 0.05). Confounding factors (smoking, medication) could not explain the gender differences noted. The concentrations of MPO and NE displayed a strong correlation (r = 0.89; P < 0.01, n = 41) but revealed no gender differences. The latter was true for concentrations of adhesion molecules as well.

Our study puts forward evidence of a gender-related difference in systemic inflammation in malnourished patients with COPD in terms of circulating neutrophils being more abundant in female patients. Among these female patients, there was also a trend toward an increase in two neutrophil-mobilizing cytokines. New and better-powered studies are warranted to confirm and characterize this potentially important phenomenon in greater detail.