Naser S A, Hulten K, Shafran I, Graham D Y, El-Zaatari F A
Department of Molecular Biology and Microbiology, University of Central Florida, Orlando, FL, USA.
Vet Microbiol. 2000 Dec 20;77(3-4):497-504. doi: 10.1016/s0378-1135(00)00334-5.
Crohn's disease (CD) is a chronic inflammatory bowel disease that is similar to Johne's disease in ruminants. Recent data have strengthened the association of M. avium subsp. paratuberculosis (M. paratuberculosis) with CD. To provide more evidence of an etiological association, antibody reactivities from CD patients were tested by immunoblotting against recombinant antigens that were identified previously from our M. paratuberculosis genomic library. Two clones (designated pMptb#40 (3.2-kb insert) and #48 (1.4-kb insert) expressing a 35K (p35)- and 36K(p36)-antigens showed specific reactivities with serum samples from CD patients. Serum samples from 75% of 53 CD patients, 14% of 35 normal individuals and 10% of 10 ulcerative colitis patients reacted to p35 antigen. Reactivities were also observed with serum samples from 89% of 89 CD patients, 14% of 50 normal controls and 15% of 29 ulcerative colitis patients reacted with p36 antigen. When the reactivity results from p35 and p36 were combined, the background from the controls was eliminated, i.e. only the CD patients reacted to both p35 and p36. The positive predictive value was 98% with specificity of 98% and the negative predictive value was 76% with sensitivity of 74% (39 positive out of 53). A statistical significance (p<0.0001) was observed when the results from CD serum samples reacting with either or both antigens were compared to the controls. The reactivity of anti-M. paratuberculosis (specifically against p35 and p36 antigens) antibodies in a significant proportion of CD patients would suggest a causal role for the organism in CD.
克罗恩病（CD）是一种慢性炎症性肠病，与反刍动物的副结核类似。近期数据进一步证实了副结核分枝杆菌（M. paratuberculosis）与克罗恩病之间的关联。为了提供更多病因学关联的证据，通过免疫印迹法检测了克罗恩病患者针对先前从我们的副结核分枝杆菌基因组文库中鉴定出的重组抗原的抗体反应性。两个克隆（分别命名为pMptb#40（插入片段为3.2 kb）和#48（插入片段为1.4 kb），表达35K（p35）和36K（p36）抗原）与克罗恩病患者的血清样本呈现出特异性反应。53例克罗恩病患者中有75%的血清样本、35例正常个体中有14%的血清样本以及10例溃疡性结肠炎患者中有10%的血清样本对p35抗原产生反应。89例克罗恩病患者中有89%的血清样本、50例正常对照中有14%的血清样本以及29例溃疡性结肠炎患者中有15%的血清样本与p36抗原发生反应。当将p35和p36的反应性结果相结合时，对照组的背景信号被消除，即只有克罗恩病患者对p35和p36均有反应。阳性预测值为98%，特异性为98%，阴性预测值为76%，敏感性为74%（53例中有39例阳性）。当将克罗恩病血清样本与一种或两种抗原反应的结果与对照组进行比较时，观察到具有统计学意义（p<0.0001）。相当一部分克罗恩病患者中抗副结核分枝杆菌（特别是针对p35和p36抗原）抗体的反应性表明该病原体在克罗恩病中起因果作用。
