This Phase I/II trial will carefully examine the safety of low-dose IL-2 in cardiovascular patients where it is currently contraindicated. The planned doses will be given to the trial patients once a day, over five days as subcutaneous injections [ i) Part A : Repeated doses will be given in the range of 0.3x10^6 IU up to a maximum of 3.0x10^6 IU (total of 25 completed patients across 5 groups: 3:2 randomisation IL-2:placebo) ii) Part B : Repeated doses will be given at doses not exceeding the maximum dose used in Part A (total of 32 completed patients across 4 groups: 6:2 randomisation IL-2:placebo)].