For example, we have observed that the concentration of IL-2 in circulation and the frequency of Tregs were increased in SLE patients with increased disease activity9, and hypothesised that low-dose IL-2 treatment may be more effective for the maintenance of clinical remission rather than treating patients with acute or flaring disease - where additional exogenous IL-2 may be functionally redundant or proinflammatory. Here, IL2 is linked to systemic lupus erythematosus.