Coronary artery ectasia and inflammatory cytokines: link with a predominant Th-2 immune response?

The role of inflammation in coronary artery ectasia (CAE) remains controversial. We evaluated the hypothesis that CAE might be associated with a specific pattern of T helper (Th) lymphocyte activation by measuring the Th-1 cytokine, interleukin-2 (IL-2) and the Th-2 cytokines, interleukin-4 (IL-4) and interleukin-6 (IL-6) in patients with CAE, obstructive coronary artery disease (CAD) and controls.

Serum levels of IL-2, IL-4 and IL-6 were measured in 74 patients undergoing an elective cardiac catheterization due to angina pectoris and positive or equivocal non-invasive screening for cardiac ischaemia: 34 had CAE and non-obstructive CAD (Group A), 22 had obstructive CAD (Group B) and 18 had normal coronaries (Group C).

Group A had significantly higher IL-4 than Group B and Group C (p<0.001 and p=0.006, respectively). In contrast, Group A had markedly lower IL-2 than Group B and Group C (p<0.001 for both comparisons). Group C had higher IL-4 and lower IL-2 than Group B (p<0.001 for both comparisons). Interleukin-6 was significantly higher in Groups A and B compared to Group C (p<0.001 for both comparisons), whilst it was comparable between Group A and Group B. Multivariate logistic regression analysis showed that higher levels of IL-4 and lower levels of IL-2 were the strongest independent predictors associated with CAE (OR: 3.846, CI: 1.677-8.822, p=0.001 and OR: 0.567, CI: 0.387-0.831, p=0.004, respectively).

Our data demonstrates that Th-2 immune response, exhibited through increased IL-4 and low IL-2, constitutes a fundamental feature of CAE.