炎症性肠病血清相关抗体检测的临床价值

Clinical value of serological auto-antibody assay in inflammatory bowel disease

[目的]研究核周型抗中性粒细胞胞浆抗体(pANCA)、抗小肠杯状细胞抗体(GAB)、抗胰外分泌腺抗体(PAB)和抗酿酒酵母菌抗体(ASCA)在炎症性肠病(IBD)诊断与鉴别诊断中的临床价值。[方法]采用间接免疫荧光薄片法检测54例溃疡性结肠炎组(UC)、17例克罗恩病组(CD)、26例肠道疾病对照组及5例正常对照组血清中4种抗体的表达。[结果]pANCA在UC组阳性率为44.4%,明显高于其他各组(P<0.01)。GAB在UC组阳性率为35.2%,与疾病对照组及正常对照组比较差异有显著性意义(P<0.05),在CD组阳性率为23.5%,与对照组比较差异无显著性意义(P>0.05);两者的表达均与UC严重程度无关。ASCA在CD组阳性率为17.6%,略高于UC组(1.9%),但两组比较差异无显著性意义(P>0.05),与疾病对照组及正常对照组比较差异亦无显著性意义(P>0.05)。PAB在实验中无一例阳性表达。联合检测4种抗体诊断IBD的敏感性、特异性和阳性阴性预测值分别为54.9%、90.3%、92.9%和46.7%。pANCA+/ASCA-诊断UC的敏感性和特异性为42.6%和94.1%,pANCA-/ASCA+诊断CD的敏感性和特异性为17.6%和100%。[结论]炎症性肠病相关抗体检测的特异性较高,但敏感性低,联合检测能明显提高敏感性。pANCA和GAB对于诊断和鉴别诊断UC较有价值,而ASCA和PAB对于诊断IBD意义不大。pANCA联合ASCA、GAB检测,对于UC和CD的鉴别诊断有一定价值。

[Objective] To investigate clinical value of assays to detect isolated and combined perinuclear anti-neutrophil cytoplasmic antibody（pANCA）,anti-intestinal goblet cell antibody（GAB）,anti-pancreatic antibody（PAB） and anti-saccharomyces cerevisiae antibody（ASCA） in diagnosis and differential diagnosis of inflammatory bowel disease（IBD）.[Methods] Serum samples were obtained from 54 patients with ulcerative colitis（UC）,17 patients with Crohn＇s disease（CD）,26 patients with other intestinal illness as disease controls and 5 normal controls.pANCA,GAB,PAB and ASCA were detected by indirect immunofluorescence assay.[Results] The positive rate of pANCA and GAB in UC were 44.4% and 35.2%,significantly higher than those in other groups（P0.01 and P0.05）.Whereas the positive rate of GAB in CD was 23.5% and there was no significant difference compared with two control groups respectively（P0.05）.There was no any association found between the presence of these two serological markers and the degree of UC.The positive rate of ASCA in CD was 17.6%,a little higher than that of UC group（1.9%）,but there was no significant difference between CD group and UC group or control groups（P0.05）.There was no PAB expressed in all of groups.The sensibility,specificity,positive and negative predictive value of combined detection of four auto-antibodies for the diagnosis of IBD were 54.9%,90.3%,92.9% and 46.7%.The combination of a positive pANCA and a negative ASCA test for the diagnosis of UC yielded a sensitivity and specificity of 42.6% and 94.1%,respectively.The combination of a negative pANCA and a positive ASCA test for the diagnosis of CD yielded a sensitivity and specificity of 17.6% and 100%,respectively.[Conclusion] Serum auto-antibody detection shows high specificity but low sensitivity in the diagnosis of IBD.The combination of tests can greatly improve the sensitivity for diagnosis.Both pANCA and GAB are useful to the diagnosis and differential diagnosis of UC.But the low positive rates of ASCA and PAB render them of little value in diagnosis of IBD.The combination of pANCA,ASCA and GAB testing is useful for the differentiation between UC and CD.