The CD8 Treg found only in post-transplant patients are considerably more potent in suppressive activity compared to the CD4+CD25high Treg cells that appear during clinical “remission” in lupus patients treated by conventional drugs, in whom autoimmune response of CD4 T cells to nucleosome-derived autoepitopes persists even during “clinical remission” (SLEDAI of zero). This evidence concerns the gene CD8A and systemic lupus erythematosus.