| Background Inflammatory bowel disease(IBD)is a chronic,non-specific inflammatory bowel disease characterized by recurrent attacks and remission.It is difficult to diagnose and treat,and seriously affects the physical and mental health of patients.The traditional diagnostic methods of IBD rely on the comprehensive analysis of clinical manifestations,endoscopy,imaging and pathological results,the diagnostic methods are complex,time-consuming,expensive,and include invasive procedures,so they are not easy to be accepted by patients.There is an urgent need for a convenient,sensitive and efficient method to assist the diagnosis of IBD.In the study of serological antibodies related to IBD,it is found that some easily available and objective serological antibodies are helpful to the early diagnosis of IBD.We have found a polypeptide fragment,as an antigen,it can selectively bind to the serum antibodies of patients with Crohn’s disease(CD),so this substance is called Crohn’s disease antibody binding polypeptide(CABP),antibody as anti-Crohn’s disease antibody binding polypeptide(anti-CABP).The objective of this study was to explore the clinical significance of anti-CABP in the diagnosis and differential diagnosis of IBD by detecting the serum levels of anti-CABP in patients with IBD.Objective To explore the clinical significance of anti-CABP in the diagnosis and differential diagnosis of IBD.Methods Clinical data and blood samples of 291 IBD patients diagnosed in the First Affiliated Hospital of Anhui Medical University from June 2017 to December 2020 were collected,including 168 patients with CD and 123 patients with ulcerative colitis(UC).170 patients with gastrointestinal polyposis were set as control group.The serum level of anti-CABP,anti-Saccharomyces cerevisiae antibody(ASCA)and perinuclear anti-neutrophil cytoplasmic antibody(p ANCA)were detected in CD,UC and control groups by using enzyme-linked immunosorbent assay(ELISA).The differences in the serum level and positive rates of anti-CABP,ASCA and p ANCA among the three groups were analyzed statistically.The diagnostic value of anti-CABP was evaluated by using receiver operating characteristic(ROC)analysis.The correlation between anti-CABP and clinical characteristics of IBD was analyzed.Results1.The levels of anti-CABP Ig A [10.82(5.51-20.68)U/ml vs 6.99(4.83-13.83)U/ml,10.82(5.51-20.68)U/ml vs 5.15(3.22-7.26)U/ml]、anti-CABP Ig G [8.11(3.51-34.12)U/ml vs 3.87(2.46-7.70)U/ml,8.11(3.51-34.12)U/ml vs 2.45(1.57-3.01)U/ml] 、 ASCA Ig G[4.95(2.19-11.02)U/ml vs 2.41(1.13-6.40)U/ml,4.95(2.19-11.02)U/ml vs2.27(1.20-4.66)U/ml] of CD patients were significantly higher than those of UC and control group(all p < 0.01).The p ANCA levels [7.83(3.84-19.98)U/ml vs2.66(1.82-3.87)U/ml,7.83(3.84-19.98)U/ml vs 1.46(1.11-1.99)U/ml] in UC patients was significantly higher than that of CD and control groups(both p<0.01).2.The positive rates of anti-CABP Ig A(16.07% vs 0.00%,16.07% vs 0.00%)、anti-CABP Ig G(34.52% vs 4.07%,34.52% vs 0.00%)、anti-CABP(42.26% vs 4.07%,42.26% vs 0.00%)、ASCA Ig G(32.74% vs 13.82%,32.74% vs 7.06%)、ASCA(38.10%vs 17.89%,38.10% vs 10.59%)in CD group were significantly higher than those in UC and control group(all p < 0.01),the positive rates of p ANCA(61.79% vs 10.71%,61.79% vs 1.76%)in UC group was significantly higher than that in CD group and control group(both p<0.01).3.In the differential diagnosis of CD and non-CD patients,the sensitivity of anti-CABP in the diagnosis of CD was 42.26%,the specificity was 98.29%,and that of positive predictive value(PPV)was 93.42%,and that of negative predictive value(NPV)was74.81%,which were better than those of ASCA(sensitivity 38.10%,specificity 86.35%,PPV 61.54%,NPV 70.87%).4.When combined detection of anti-CABP and ASCA,the sensitivity of diagnosing CD can be increased to 66.07%.When combined detection of anti-CABP and p ANCA,the specificity of diagnosing CD can be increased to 100.00%.5.The area under the ROC curve(AUC)of anti-CABP is 0.816,which is better than that of ASCA(AUC 0.680).The combined use of anti-CABP,ASCA,p ANCA can improve the diagnostic efficiency(AUC 0.857).6.The positive rates of anti-CABP Ig A in CD patients with or without perianal lesions were significantly different(p < 0.05),and the positive rates of anti-CABP Ig G and anti-CABP were significantly different in the disease locations of CD patients(p <0.05).Conclusion1.The serum levels of anti-CABP Ig A and anti-CABP Ig G in CD group were higher than those in UC and control groups,the positive rate of anti-CABP in CD group was significantly higher than that in UC and control group,suggesting that anti-CABP could be used as a serological marker to assist the diagnosis and differential diagnosis of CD.2.The sensitivity,specificity and diagnostic efficacy of anti-CABP in the diagnosis of CD were better than those of ASCA.3.When antibody was used in combination,combined detection of anti-CABP and ASCA can improve the sensitivity of CD diagnosis.Combined detection of anti-CABP and p ANCA can improve the specificity of CD diagnosis.Combined detection of anti-CABP,ASCA and p ANCA can improve the diagnostic efficiency of CD.4.The positive rates of anti-CABP Ig A were related to the presence or absence of perianal lesions in CD patients,and the positive rates of anti-CABP Ig G and anti-CABP were significantly correlated with the location of disease in CD patients. |
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