Macrophage stimulation and activity in lepromatous leprosy

Abstract

It is generally accepted that in untreated lepromatous infections there is a wide range of variation in the morphological index, which is sometimes unaccountably low. However, while the level of activity in untreated leprosy is fairly uniform in relapse it may vary greatly from lesion to lesion. Some leprosy lesions exhibit cytological and proliferative evidence of a form of non-specific stimulation that is commonly associated either with adjuvants or with organisms which excite a strong immunological response. High antibody levels might in theory help to explain both the cellular and bacteriological activity, and in part the immunological failure of lepromatous leprosy. It would not be surprising if in relapse, which represents in effect a second infection, there might be a sharp rise in antibody levels, which on this hypothesis would stimulate bacteriological activity in those lesions where renewed activity was originating. However, there is no direct evidence to substantiate a governing role for bacterial antibody on the kinetics of the granuloma. Clinico-pathological observations give strong grounds for thinking that the total antigenic load is directly correlated with immuno-depression, and that it must be one of the most important determinants of macrophage performance. It would appear that the prime factors that stimulate or allow activity in lepromatous leprosy, cellular and bacterial, are vagaries of certain factors that are amongst those responsible for inducing immuno-depression. For this reason alone the question of activity deserves further study.