HIV-specific CD8+ T cells are more likely to express CD57 than non-HIV-specific CD8+ T cells [3], and CD57 expression is increased on the total memory CD8+ T cell population in HIV infection [4], [5], but much of this increase could be explained by relative enrichment for effector CD28- CD8+ T cells over central memory and naïve CD8+ T cells (which rarely express CD57). This evidence concerns the gene CD28 and HIV infectious disease.