Immunological problems in leprosy research. 1. Clinical and pathological spectrum of leprosy.

This paper discusses the evidence for and against the view that the spectrum of pathological changes in leprosy, extending from the lepromatous form to the tuberculoid form, may be caused by differences in the immune responses of patients. Patients with the tuberculoid form of leprosy generally have well-developed specific cell-mediated immunity, but in a large proportion of patients with lepromatous leprosy the specific cell-mediated immunity to Mycobacterium leprae and sometimes to other antigens seems to be deficient, whereas the circulating antibody response is well-developed. Techniques for assessing the immune response in patients are described in detail with the objective of improving the comparability of such investigations. The paper also discusses the importance of several investigatory approaches to clinical leprosy and the value of animal models for leprosy research.