Interestingly, equal numbers of Tregs from the SLE patients studied, regardless of disease activity status, expressed similar amounts of cell surface CD25 as the controls when measured by FACS (data not shown) but had less pSTAT5 30 minutes following low dose IL-2 activation in vitro and had a more rapid loss of pSTAT5 expression than that seen in Tregs from healthy controls when stimulated with low dose IL-2 (Figure 2). Here, IL2 is linked to systemic lupus erythematosus.