CD4 and systemic lupus erythematosus: We found that EGR2 mRNA expression levels were significantly upregulated in purified splenic CD4+ T cells from diseased MRL-lpr (14–15 weeks-of-age, Fig. 1c), B6-lpr (18 weeks-of-age, Fig. 1d) and B6.sle123 (27–32 weeks of age, Fig. 1d) lupus mice when compared to their respective controls (MRL and B6 mice).