Infectious granulomas: exposit from the leprosy model.

Abstract

Understanding the immunopathology of leprosy has depended largely on our understanding of other diseases, notably tuberculosis. Thus, Danielssen and Boeck's 1847 Atlas de Colode de Spedalskhed followed on an under­ standing of the pathology of tuberculosis derived from the work of Richard Morton, Matthew Baillie, Gaspard-Laurent Bayle, and Rene Laennec. Hansen's recognition of the Bacillus leprae as leprosy's etiologic agent cautiously antedated Koch's announcement concerning the tubercle bacil­ lus, but followed Marten's 1720 astute speculations regarding the causation of infectious disease and Villemin's experiments (1865 and 1868) demon­ strating that human tuberculosis could be transmitted to experimental ani­ mals. Mitsuda and Hayashi's development of the lepromin test was patterned after Koch's work on the tuberculin test. Just as Koch's efforts were initially directed at developing an immunizing, rather than a diagnos­ tic, procedure, so also were Mitsuda and Hayashi's efforts regarding lep­ rosy. The very term tuberculoid, first used definitively in 1898 in reference to leprosy by Jadassohn, by itself speaks to this interrelationship and derivative understanding. A number of remarkable features of leprosy may now contribute to a more general understanding of other infectious granulomas (I, 2). The intergraded and graded histopathologic and immunologic responses pre­ sented by leprosy flow from tuberculoid to lepromatous via a range of