MTB-specific lymphocytes are selectively recruited to the site of infection in active pulmonary tuberculosis

Background: Lymphocytes are crucial in the immune defense against Mycobacterium tuberculosis (MTB) infection. We ascertained whether MTB-specific lymphocytes are selectively recruited into the lungs of patients with active pulmonary tuberculosis. Material and methods: We prospectively recruited patients with smear-negative, MTB culture-confirmed pulmonary tuberculosis. Differential cell counts, immunophenotyping with monoclonal antibodies against cell surface markers CD4, CD8, HLADR, CD45RO, CD45RA and MTB-specific enzyme linked immunospot assays (ELISPOT) with early secretory antigenic target 6 (ESAT-6) and cul…