Elimination of Mycobacterium leprae subsequent to local in vivo activation of macrophages in lepromatous leprosy by other mycobacteria.

This investigation studied the possibility of activating lepromatous macrophages by a local ' test. Lepromatous macrophages have an evident incapacity for clearing . This is demonstrated by injecting lepromatous patients with an antigen containing from human tissue at a concentration of 640 × 10 bacteria per ml. This produces a nodule which, at a 30-day biopsy, shows a macrophagic granuloma with numerous bacteria inside the macrophages, proving that these cells are unable to remove . This incapacity is specific for , and all other mycobacteria produce a different reaction. Local ' stimulation of the lepromatous macrophage was obtained by injecting in the same concentration as above but mixed with other mycobacteria ( or BCG). The mixed antigens produced a tuberculoid granuloma with abundant lymphoid cells. Fite–Faraco stains showed almost no acid-fast bacteria. Therefore, our mixture of antigens had activated the macrophages locally and made them competent for clearing .