Immunoregulation of cytokines in infectious diseases (leprosy), future strategies.

Leprosy is a dynamic disease model in which distinct Mycobacterium leprae-responsive T cell subsets play an important role in host defense and control clinical and immunological spectrum. Th1 cells are associated with tuberculoid leprosy patients that have strong M. leprae-specific CMI-DTH responses. Th2 cells are expressed in lepromatous leprosy patients that are characterized by strong humoral immune responses and lack of T cell responses. Recently cytokines are thought to play immunoregulatory role in both the protection and immunopathogenesis of the host. Recombinant cytokines for immunotherapy have been used for controlling mycobacterial infections including leprosy. The diversity of T-cell subsets contributing to Th1 and Th2 cell derived cytokines, other major cytokines of the immune system, their sources, modes of action and possible therapeutic potentials are discussed.