Human Mycobacterium tuberculosis-reactive CD4+ T-cell clones: heterogeneity in antigen recognition, cytokine production, and cytotoxicity for mononuclear phagocytes

Tuberculosis: commentary on a reemergent killer

Tuberculosis remains the leading cause of death in the world from a single infectious disease, although there is little knowledge of the mechanisms of its pathogenesis and protection from it. After a century of decline in the United States, tuberculosis is increasing, and strains resistant to multiple antibiotics have emerged. This excess of cases is attributable to changes in the social structure in cities, the human immunodeficiency virus epidemic, and a failure in certain major cities to improve public treatment programs. The economic costs of not adequately addressing the problem of tuberculosis in this country are estimated from an epidemiological model.

Macrophages, mycobacteria and HIV: the role of cytokines in determining mycobacterial virulence and regulating viral replication

The marriage of two scourges, one old (mycobacterial disease) and one new (HIV), has presented an enormous challenge to the medical and public health communities, and has stirred renewed interest in mechanisms for immune control of mycobacterial infection. Virulence of both M. avium and M. tuberculosis appears to be inversely related to the capacity of the microorganisms to induce production of protective cytokines in infected hosts. TNF alpha and IFN gamma are central to this process, and mycobacterial polysaccharides may be their main determinant. Despite these similarities, M. tuberculosis and M. avium cause illnesses at the polar extremes of HIV disease. Tuberculosis, occurring early in the course of HIV disease, may promote HIV replication in otherwise latently infected cells via induction of cytokines. As such, the potential exists for accelerated progression to AIDS due to the mutual synergy of these pathogens.