Intracellular survival of Mycobacterium tuberculosis in macrophages is modulated by phenotype of the pathogen and immune status of the host.

Emerging evidence indicates that the causative agent of tuberculosis is more genetically and functionally diverse than appreciated previously. The impact of this variation on the clinical manifestation of the disease remains largely unknown. In addition, there exists significant variability in the immune status of the host governing susceptibility to tuberculosis.

Suspected small-scale interpersonal transmission of Mycobacterium tuberculosis in wards of an urban hospital in Delhi, India.

Genotypes of Mycobacterium tuberculosis causing disease were investigated in pulmonary tuberculosis patients admitted to two adjacent wards of a tuberculosis hospital in Delhi, India. Genetic markers, the insertion sequence IS6110, a direct repeat sequence, and a polymorphic GC-rich sequence supported the circumstantial epidemiologic link between eight strains of M. tuberculosis, suggesting their possible involvement in small-scale, interpersonal transmission of both drug-sensitive and drug-resistant tuberculosis.

Dysregulation of homeostasis of blood T-lymphocyte subpopulations persists in chronic multibacillary pulmonary tuberculosis patients refractory to treatment.

Design: The dysregulation of homeostasis of blood-T lymphocyte subpopulations was studied in 21 cases of chronic, multibacillary pulmonary tuberculosis refractory to treatment. The clinico-bacteriological and immunological parameters studied in these cases (Gr A) were compared with those of a group of 10 newly-diagnosed drug sensitive cases of pulmonary tuberculosis (Gr B) at the beginning of the study and after 3 months of chemotherapy for tuberculosis. The chronic cases were treated with drugs selected from a reserve line.

Peripheral blood T lymphocyte subpopulations in patients with tuberculosis and the effect of chemotherapy.

Peripheral blood T lymphocytes and their subsets were determined in 30 patients with pulmonary tuberculosis (15 smear positive and 15 smear negative) and 11 healthy individuals. All patients were assessed clinically, radiologically, bacteriologically and by tuberculin testing, and their lymphocyte counts were repeated after completion of 3 months chemotherapy. The mean ratio of putative helper/suppressor T cell subsets (CD4/CD8) of healthy individuals was 1.