Sterne J A, Fine P E, Pönnighaus J M, Rees R J, Chavula D
Department of Public Health Medicine, United Medical and Dental Schools of Guy's and St Thomas's Hospitals, London, UK.
Int J Epidemiol. 1998 Aug;27(4):713-21. doi: 10.1093/ije/27.4.713.
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.
More than 15000 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.
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.
Our results suggest that the 'second-generation' batches have lost antigens that can detect M. leprae infections, but that they retain one or more antigens which are shared between M. leprae and environmental mycobacteria. Natural exposure to these both sensitizes individuals and provides natural protection against M. leprae infection or disease. Identification of antigens present in these groups of skin test reagents may assist in production of improved skin test reagents.
麻风分枝杆菌（M. leprae）可溶性抗原（MLSA）试剂已被开发出来，目的是找到一种与结核菌素相当的试剂，能够识别感染麻风杆菌的个体。它们尚未在人群中得到充分评估。
超过15000名生活在马拉维北部麻风流行地区的个体，用使用两种不同方案制备的五批MLSA中的一批进行了皮肤试验。制备过程中的主要差异在于后三批（“第二代”）在制备过程中引入了高G离心步骤。
第一代（批次A6、A22）试剂的皮肤试验阳性率（迟发型超敏反应（DTH））及与卡介苗疤痕存在的相关性高于第二代（批次AB53、CD5、CD19）试剂。通过比较麻风病例已知（家庭）接触者、新诊断的麻风患者与普通人群的结果，研究了阳性与麻风分枝杆菌感染的相关性。虽然对“第一代”抗原的阳性似乎与麻风分枝杆菌感染有关，但对后来抗原的阳性与接触麻风病例或麻风病的存在均无关。不同批次的DTH患病率存在地理差异，这可能反映了环境中接触各种分枝杆菌的情况。
我们的结果表明，“第二代”批次失去了能够检测麻风分枝杆菌感染的抗原，但保留了一种或多种麻风分枝杆菌与环境分枝杆菌共有的抗原。对这些抗原的自然接触既能使个体致敏，又能提供针对麻风分枝杆菌感染或疾病的天然保护。鉴定这些皮肤试验试剂组中存在的抗原可能有助于生产改进的皮肤试验试剂。
