Increased circulating interleukin (IL)-10 is reported in patients with acute myocardial infarction (AMI)1 and in mice with myocardial ischaemia/reperfusion2; induction of IL-10 mRNA in ischaemic/reperfused myocardium3 was also recently reported. Ischaemic/reperfused myocardium is protected by IL-10 through inhibition of tumour necrosis factor α production2 and down regulation of IL-6 mRNA in a canine model.3 We have already shown induction of circulating IL-6, and a positive relation between natriuretic peptides in AMI.4 We also showed IL-6 expression in ischaemic myocardium5; however, no study has investigated circulating concentrations of IL-6 and IL-10 at the same time. Increased IL-10 inhibited IL-12 induction in an animal model,3 while circulating IL-12 has not been investigated in patients with AMI. In this study we show a reciprocal increase in circulating IL-10 and IL-6, but not IL-12, in patients with AMI.

Twenty patients admitted to Fujioka Hospital within six hours of the onset of AMI symptoms, and 20 healthy controls, were enrolled after informed consent was obtained. In patients with AMI, informed consent was …