Apolipoprotein E genotype and circulating interleukin-10 levels in patients with stable and unstable coronary artery disease.

OBJECTIVES: This study was designed to assess the relation between apolipoprotein E (apoE) genotype and serum interleukin (IL)-10 levels in patients with acute coronary syndrome (ACS) and chronic stable angina (CSA).
BACKGROUND: Genetic variations in the apoE gene affect the risk for coronary artery disease (i.e., carriers of the e4 allele have an increased risk). Increased levels of C-reactive protein (CRP), an inflammatory marker, correlate with an increased risk of acute coronary events, whereas increased IL-10 concentrations have an atheroprotective role. Studies have reported a negative association between the apoE e4 allele and CRP levels.
METHODS: Apolipoprotein E genotypes were assessed in 166 consecutive ACS patients (119 men, mean age 68 years, interquartile range [IQR] 60 to 74 years) and 70 CSA patients (54 men, mean age 65 years, IQR 62 to 68 years). Serum IL-10 and CRP were assessed at study entry.
RESULTS: Analysis of covariance showed that genetic variation in the apoE gene locus significantly influences serum IL-10 levels in both ACS (p = 0.009) and CSA patients (p = 0.013). Among ACS patients, IL-10 levels were lower in E3/E4 carriers compared with E3/E3 carriers (p = 0.01) and marginally lower compared with E2/E3 carriers (p = 0.065). Among CSA patients, IL-10 levels were lower in E3/E4 carriers compared with E2/E3 carriers (p = 0.004) and marginally lower compared with E3/E3 carriers (p = 0.086).
CONCLUSIONS: The IL-10 concentrations differ in ACS and in CSA patients with different apoE genotypes. The e4 allele was associated with a trend toward lower IL-10 serum levels. Our results may provide an explanation of findings in previous studies that cardiovascular risk is higher in e4 carriers despite the presence of low CRP levels.