Immune dysregulation in human tuberculosis.

Hyporesponsiveness to mycobacterial antigens occurs in some patients with tuberculosis. Active immunosuppression by monocytes, T-lymphocytes, and serum is evident and may be a critical factor in anergy. The molecular basis for depressed responsiveness to tuberculin antigens is uncertain, but may involve aberrant surface expression of the HLA-DR gene product on adherent mononuclear cells and abnormalities in immune induction and the cytokine cascade.