血清抗微生物抗体检测对炎症性肠病诊断的临床意义

Clinical significance of serum anti-microbial antibodies test in inflammatory bowel disease

目的：探讨抗酿酒酵母抗体（ASCA）、大肠埃希菌外膜孔道蛋白 C 抗体（anti-Omp C）、荧光假单胞菌相关序列 I2抗体（anti-I2）、细菌鞭毛蛋白抗体（anti-CBirl）在 IBD 诊治中的临床意义。方法收集2011年至2013年 IBD 患者87例，分为 CD 组、UC 组，其中 CD 组66例，UC 组21例，并根据IBD 患者的年龄及男女比例收集健康对照组62名。空腹采集受试者静脉血2 mL，使用 ELISA 试剂盒检测血清中的 ASCA，anti-OmpC，anti-I2和 anti-CBirl 4种抗微生物抗体的表达。分别绘制 ROC 曲线比较各抗体对 IBD，以及 UC 与 CD 的诊断和鉴别诊断意义。结果ASCA 在区分 IBD 与健康对照组、CD 组与 UC 组的 AUC 分别为0．580，0．512，有较低的诊断准确性。anti-CBirl 在区分 IBD 与健康对照组的 AUC 为0．617，其余血清抗体在各组间比较无鉴别诊断意义。ASCA 在 IBD 组的阳性率分别为62．1％（54/87），显著高于健康对照组的38．7％（24/62）。anti-OmpC，anti-I2在 IBD 组的阳性率显著低于健康对照组，差异均有统计学意义（P 均＜0．05），其余各对比组间血清抗体的阳性率差异均无统计学意义（P 均＞0．05）。ASCA 阳性鉴别 CD 与 UC 的特异度、敏感度、阳性预测值和阴性预测值分别为52．4％、66．7％、81．48％、33．33％，anti-OmpC，anti-I2和 anti-CBirl 鉴别 CD 和 UC 的特异度在81．0％～100．0％，敏感度在9．1％～37．9％。联合 ASCA 阳性或 anti-I2阳性诊断 CD 的特异度、敏感度、阳性预测值和阴性预测值分别为57．1％、86．4％、82．6％、50．0％。CD 患者中 ASCA 或 anti-I2的阳性率显著高于 UC 组[84．8％（56/66）比57．1％（12/21）]，差异有统计学意义（χ2＝5．633，P ＝0．018）。结论ASCA 阳性对于中国 IBD 患者的检测有一定意义，检测 anti-I2可用于 ASCA 阴性 CD 患者的辅助诊断。anti-OmpC和 anti-CBirl 由于敏感度和阳性率均较低，对于国人诊断 IBD，以及鉴别 UC 和 CD 意义不大。

Objective To investigate the clinical significance of serum anti-Saccharomyces cerevisias antibody （ASCA）,anti-outer membrane porin C （anti-OmpC）,antibody to Pseudomonas fluorescens-associated sequence I2 （anti-I2 ）and antibody to bacterial flagellin （anti-CBirl ）in the diagnosis and treatment of inflammatory bowel disease （IBD）.Methods From 2011 to 2013,87 patients with IBD were enrolled and divided into Crohn′s disease （CD）group （66 cases）and ulcerative colitis （UC）group （21 cases）.A total of 62 age and gender matched healthy individuals were enrolled as the control group. Fasting blood samples （2 mL）of the subjects were collected.The expression of ASCA,anti-OmpC,anti-I2 and anti-Cbirl antibodies was detected with enzyme-linked immunosorbent assay （ELISA）kits.The diagnosis value of each antibody in IBD and the differential diagnostic value of in UC and CD were compared by receiver operating characteristic （ROC）curve.Results The area under the curve （AUC）of ASCA between IBD and the healthy control group,between CD group and UC group was 0.580 and 0.512, respectively;the accuracy in diagnosis was low.The AUC of anti-CBirl between IBD and the healthy control group was 0.617.There was no differential diagnosis significance of the other antibodies.The positive rate of ASCA in IBD group was 62.1 % （54/87）,which was significantly higher than that in the control group （38.7%,24/62）.The positive rates of anti-OmpC and anti-I2 in IBD group was significantly lower than those in the control group and the differences were statistically significant （both P 〈0.05）.No difference was observed in positive rates of serum antibodies among the others groups （all P 〉0.05）.The specificity,sensitivity,positive predictive value （PPV）and negative predictive value （NPV）of ASCA in differential diagnosis of CD and UC was 52.4%,66.7%,81 .48% and 33.33%,respectively.The specificity and sensitivity of anti-OmpC,anti-I2 and anti-CBirl in differential diagnosis of CD and UC was 81 .0% to 100.0% and 9.1 % to 37.9%,respectively.The specificity,sensitivity,PPV and NPV of double-positive ASCA and anti-I2 in the diagnosis of CD was 57.1 %,86.4%,82.6% and 50.0%, respectively.The positive rate of ASCA and anti-I2 in CD group was significantly higher than that in UC group （84.8%（56/66）vs 57.1 % （12/21 ）;χ2 =5 .633,P =0.018 ）.Conclusions Positive ASCA has some significance in the diagnosis of patients with IBD in our country.The detection of anti-I2 can help to diagnose ASCA negative CD.Because of low sensitivity and positive rate,anti-OmpC and anti-CBirl have limited value in the diagnosis of IBD and the differential diagnosis of UC and CD in our country.