Interleukin 1--a possible mediator of neural fibrosis in leprosy.

Neural fibrosis in leprosy, the disease caused by the obligate intracellular bacterium, Mycobacterium leprae, is closely related to the cell-mediated immune response to this microorganism. The fibrosis appears to be due to soluble mediators released by the immune effector cells. Interleukin 1, a macrophage product that stimulates fibroblast migration, proliferation and synthetic activity, possesses the requisite properties to qualify for such a mediator.