Bcl, BAK, and BAX are the key regulators of apoptosis, with Bcl being an anti-apoptotic member and BAK and BAX being pro-apoptotic members, which are capable of regulating the life or death of a cell that plays an essential role in a variety of infections stresses; thus, changes in Bax, BAK, and Bcl-2 expressions can directly reflect the apoptotic status of the cell. The gene discussed is BCL2; the disease is infection.