Résumé :
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[BDSP. Notice produite par INIST m2R0xj11. Diffusion soumise à autorisation]. Background Mycobacterium leprae (M. leprae) soluble antigen (MLSA) reagents have been developed with the aim of finding a reagent, comparable to tuberculin, which could identify individuals infected with the leprosy bacillus. They have yet to be evaluated fully in human populations. Methods More than 15 000 individuals living in a leprosy endemic area of northern Malawi were skin tested with one of five batches of MLSA prepared using two different protocols. The main difference in preparation was the introduction of a high G centrifugation step in the preparation of the last three ('second-generation') batches. Results The prevalence of skin-test positivity (delayed-type hypersensitivity (DTH)) and association with the presence of a BCG scar were greater for first (batches A6, A22) than second (batches AB53, CD5, CD19) generation reagents. The association of positivity with M. leprae infection was investigated by comparing results among known (household) contacts of leprosy cases, and among newly diagnosed leprosy patients with those in the general population. While positivity to'first-generation'antigens appeared to be associated with M. leprae infection, positivity to later antigens was unrelated either to exposure to leprosy cases or presence of leprosy disease. There were geographical differences in the prevalence of DTH to the various batches, probably reflecting exposure to various mycobacteria in the environment, Conclusions Our results suggest that the'second. (...)
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