The most commonly used chemotherapeutic agent in leprosy is DDS. However, as
could be expected with monotherapy, a considerable proportion of lepromatous cases will
relapse with drug resistant strain of M. leprae. Other drugs, such as clofazimine and
rifampicin, are so expensive that they have only a very limited use at present.
Moreover, all chemotherapeutic agents, although they may be efficient in killing M.
leprae, apparently do not alter the body's capacity to eliminate the dead bacilli, which
may continue to release antigen for prolonged periods of time and thereby give rise to
erythema nodosum leprosum. Finally, since the anergic state in lepromatous patients
appears to be lifelong, such patients will have to remain permanently on anti-leprosy
chemotherapy, unless cell-mediated immunity to M. leprae can be induced. For this
reasons, there is a need for additional treatment methods such as immunotherapy. The
aims of immunotherapy may to increase digestion of M. leprae and thereby reduce ENL
reaction and the induce impunity in treated lepromatous patients, and thereby reduce the
risk of development of DDS-resistant cases and make termination of anti-leprosy
chemotherapy possible.
On our histopathological study of lepromatous nodule eight weeks after BGG local
injection into the leproma, it was observed that M. leprae was lysed rapidly and
bacterial index became nearly negative and histological findings showed borderline
leprosy. This results suggest that one might expect eventual systemic manifestations of
cellular immunity to M. leprae by BCG immunotherapy in lepromatous leprosy.
Therefore, the immunotherapy trial with BCG repeated injection to lepromatous
patients being admitted in Korean Leprosy Institute has been carried out for more than
fifteen months and the following results were obtained.
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