We have previously noted reduced peripheral blood mononuclear cell (PBMC) cytokine production and CD4+ T-lymphocytes in HIV-seronegative adults with previous EPTB compared to persons with previous pulmonary TB or LTBI (12).We also found that persons with previous EPTB had increased T-regulatory (Treg) cell frequency and CD4+ lymphocyte activation, indicating possible immune dysregulation (13). The gene discussed is CD4; the disease is pulmonary tuberculosis.