Circulating interleukin-10: association with higher mortality in systolic heart failure patients with elevated tumor necrosis factor-alpha.

Background: Interleukin-10 is an anti-inflammatory cytokine and consequently is considered by many to have a protective role in heart failure, as opposed to the notorious tumor necrosis factor-alpha.

Objectives: To test the hypothesis of the possible beneficial impact of IL-10 on mortality in systolic heart failure patients in relation to their circulating TNFalpha levels.

Methods: We measured circulating levels of IL-10 and TNFalpha in 67 ambulatory systolic heart failure patients (age 65 +/- 13 years).

Results: Mortality was or tended to be higher in patients with higher levels (above median level) of circulating TNFalpha (9/23, 39% vs. 6/44, 14%; P = 0.02) or IL-10 (10/34, 30% vs. 5/33, 15%; P = 0.10). However, mortality was highest in the subset of patients with elevation of both markers above median (7/16, 44% vs. 8/51, 16%; P = 0.019). Elevation of both markers was associated with more than a threefold hazard ratio for mortality (HR 3.67, 95% confidence interval 1.14-11.78).

Conclusions: Elevated circulating IL-10 levels in systolic heart failure patients do not have a protective counterbalance effect on mortality. Moreover, patients with elevated IL-10 and TNFalpha had significantly higher mortality, suggesting that the possible interaction in the complex inflammatory and anti-inflammatory network may need further study.