Association of apoptosis and TGF-β1 Activation Index. (a) Percentage of PBMCs undergoing apoptosis: control individuals versus SLE patients. Cells were stained with annexin-V and propidium iodide to differentiate early apoptotic cells from necrosing and late apoptotic cells. The thick horizontal bar denotes the median, and the whiskers show the interquartile range. Significance was calculated using the Mann-Whitney U test. (b) Degree of apoptosis in PBMCs from patients and TGF-β1 Activation Index are correlated, using Pearson test. PBMC, peripheral blood mononuclear cell; SLE, systemic lupus erythematosus; TGF, transforming growth factor.