Learning from leprosy: insight into the human innate immune response.

Investigation into the innate immune response in leprosy has provided insight into host defense and immunopathology in human infectious disease. A key advance has been the delineation of pattern recognition receptors that detect pathogen-associated molecular patterns of the bacterium that causes leprosy, Mycobacterium leprae. From this knowledge, it has been possible to determine the cytokine responses as well as macrophage and dendritic cell differentiation programs that contribute to host defense and tissue injury in leprosy. These insights provide targets for therapeutic intervention to modulate innate immune responses against microbial infection in humans.