CD28 and systemic lupus erythematosus: CD4+ T cells and CD4+/CD8+ levels were decreased, and memory function with visuospatial domains was negatively correlated with memory T cells (CD4+ CD45RO+ T cells and CD8+ CD28− T cells), confirming that accelerated immune senescence in SLE patients led to cognitive dysfunction, especially in attention deficit, recall, and visuospatial domains.