Another study carried out by the Dheda team found that, in peripheral blood mononuclear cell (PBMC) cultures stimulated with tuberculosis antigen, the most stable genes were HuPO and HPRT whereas GAPDH, B2M, ACTB and EIF-1-α (elongation factor 1-α)4 were less stable genes. The gene discussed is ELOF1; the disease is tuberculosis.