Clinical Significance Of Serum Antibody In 160 Cases Of Inflammatory Bowel Disease

Objective:To explore the clinical value of perinuclear anti-neutrophil cytoplasmicantibody(pANCA),anti-saccharomycescerevisiae antibodies(ASCA),antibodies against exocrine pancreas(PAB)and antibodies to intestinal goblet cells(GAB)in IBD.Methods:Serum samples were obtained from 160 consecutive IBD patients from January 2013 to December 2016 at the First Bethune Hospital of Jilin University.Among them,there were 120 cases of UC,40 of which were CD,and 40 patients with digestive tract disease of non-IBD were included as the control group.Four antibody in serum were detected by indirect immunofluorescence assay.Results:(1)Single antibody detectionIn the UC group,CD group and control group,the positive rate of p ANCA was 73.3%,25.0%and 17.5%respectively,and the UC group was significantly higher than the latter two groups(c2=29.528 and38.771 respectively,P<0.001 for all).The positive rate of GAB was17.5%,32.5%and 10.0%respectively,and the CD group was significantly higher than the other two groups(c2=4.034 and 6.050respectively,P=0.045 and 0.014 respectively).The positive rate of ASCA was lower,which was 3.3%,17.5%and 5.0%,respectively,but the CD group was significantly higher than that of UC group(c~2=7.322,P=0.007).The positive rate of PAB was 35.0%,27.5%and 17.5%respectively,and the UC group was significantly higher than the control group(c~2=4.324,P=0.038).(2)Combined antibody detectionThe specificity of combination of positive pANCA and negative GAB in the differential diagnosis of UC and CD was 82.5%,the positive predictive value was 91.0%.The specificity of combination of positive GAB and negative pANCA in the differential diagnosis of CD and UC was 96.7%and the positive predictive value was 71.4%.The specificity of combination of positive pANCA and negative ASCA in the differential diagnosis of UC and CD was 80.0%,the positive predictive value was 91.4%.The specificity of combination of positive ASCA and negative pANCA in the differential diagnosis of CD and UC was 99.2%and the positive predictive value was 83.3%.(3)Relationshipbetween antibodyexpressionanddisease characteristicsIn UC patients,there was no statistically significant difference of the positive rate of the four antibodies in the diagnosis ageand lesion locations(P>0.05).In patients with CD,there was no significantly statistical difference of the positive rate of pANCA?ASCA and PAB in the diagnosis age and disease behaviors(P>0.05);but the difference of the positive rate of GAB between different disease behaviors was statistically significant(c2=4.748,P=0.029),53.3%of them were prone to perianal lesions.The positive rates of pANCA,PAB,and GAB were also not statistically different among different lesionlocations(P>0.05).However,the difference of the positive rate of ASCA between different lesion locations was statisticallysignificant(c2=8.219,P=0.042),60%of them occurred at the terminal ileum.(4)Relationship between antibody expression and treatmentIn the UC group and the CD group,there was no obviously statistical difference in the positive rates of the four antibodies among different treatment methods(P>0.05).Conclusion:1.In the results of this study,pANCA is consistent with most of the studies and is a specific antibody for UC that can be used for thediagnosis and differential diagnosis of IBD.2.There are significant difference between ASCA,GAB and PAB:(1)The sensitivity of ASCA is obviously low,which can only be used for differential diagnosis of confirmed IBD;(2)The GAB positive is more common in CD,it is a specific antibody of CD,witch is helpful for CD screening;(3)PAB positive is more common in UC,but it is not suitable for the diagnosis and differential diagnosis of IBD alone.This may be related to the selection of samples,genetic background of population,and different experimental methods.3.The combined antibody detection significantly improved the test efficacy.The combination of pANCA and GAB is helpful for thediagnosis and differential diagnosis of IBD,and pANCA combined with ASCA helps in differential diagnosis of confirmed IBD.4.CD patients with GAB-positive were prone to perianal lesions.The lesions of ASCA-positive CD patients tended to involve theterminal ileum.