The predominance of TCRβ+CD138+ cells presenting with memory phenotype and the suppression of CD138-expression with rapamycin (Supplemental Figure 2H) in MRL/Lpr mice suggest that mTOR mediated expansion of CD138-expressing memory T cells may be associated with lupus pathogenesis in MRL/Lpr mice as well as in SLE patients. This evidence concerns the gene SDC1 and systemic lupus erythematosus.