Circulating, Mycobacterium tuberculosis-specific lymphocytes from PPD skin test-negative patients with tuberculosis do not secrete interferon-gamma (IFN-gamma) and lack the cutaneous lymphocyte antigen skin-selective homing receptor. - Magnani ZI; Confetti C; Besozzi G; Codecasa LR; Panina-Bordignon P; Lang R; Rossi GA; Pardi R; Burastero SE (Clinical and experimental immunology, 2000)