In addition to the numerous upregulated genes related to cell cycling andcytokine production, both lpr DN T cells and SLE DN2 B cells alsomanifest upregulation of the cell cycle checkpoint blocker PD-1(Pdcd1) and IL-10, and the sites of both genes correspond tosites of demethylation (16). The gene discussed is PDCD1; the disease is systemic lupus erythematosus.