Association of plasma PCSK9 levels with white blood cell count and its subsets in patients with stable coronary artery disease.

Objective: Recent studies have suggested that proprotein convertase subtilisin/kexin type 9 (PCSK9) is associated with atherosclerosis and plays a potential role in inflammation. However, the correlation between PCSK9 and white blood cell count (WBCC) has not yet been assessed. The objective of the present study was to examine the association of the WBCC and its subset counts with plasma PCSK9 levels in patients with stable coronary artery disease (CAD).
Methods: In this cross-sectional study, a total of 251 consecutive, stable CAD patients who were not treated with lipid-lowering drugs were enrolled at our center between October 2012 and October 2013. The baseline clinical characteristics were collected, and the plasma PCSK9 levels were determined using ELISA. The associations of plasma PCSK9 levels with the WBCC and its subsets were investigated.
Results: In the overall population, plasma PCSK9 levels were positively associated with the WBCC (r = 0.167, p = 0.008). Multivariable regression analysis revealed that the plasma PCSK9 levels were significantly and independently associated with the WBCC (β = 0.217, p < 0.001) and its subsets (neutrophil β = 0.152, p < 0.05; lymphocyte β = 0.241, p < 0.001). However, the relationships between PCSK9 and WBCC and its subsets remained significant in men (WBCC r = 0.234, p = 0.001; neutrophil r = 0.181, p = 0.014; lymphocyte r = 0.226, p = 0.002) but were not significant in women when the analysis was performed based on gender.
Conclusions: These data demonstrate that the plasma PCSK9 levels are independently associated with the WBCC and its subsets, suggesting a potential interaction between PCSK9 and chronic inflammation in patients with CAD.
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