CD28 and systemic lupus erythematosus: After stimulation with a combination of αCD3/CD28 soluble antibodies for 6 days, there was an overall induction of Bcl-XL and Mcl-1 in the total T cell populations (Figs. 4 and 5) but no differences in expression levels of Bcl-2 family members were measured in SLE/RA patient samples and healthy controls (Fig. 5).