Clinical Significance of Perinuclear Antineutrophil Cytoplasmic Antibodies and Anti-Saccharomyces cerevisiae Antibodies in Inflammatory Bowel Disease

Background:Perinuclear antineutrophil cytoplasmic antibodies(pANCA) and anti-Saccharomyces cerevisiae antibodies(ASCA) are immunoglobulins closely related with inflammatory bowel disease(IBD).The role of pANCA and ASCA in the diagnosis of ulcerative colitis(UC) and Crohn's disease(CD) remains further verification.Aims:To investigate the significance of pANCA and ASCA in the diagnosis and differential diagnosis of UC and CD.Methods: Serum samples were obtained from 64 patients with UC,62 patients with CD and 56 healthy controls.Levels and positivity rates of pANCA and ASCA were determined by enzyme-linked immunosorbent assay(ELISA).The sensitivity,specificity, positive predictive value(PPV) and negative predictive value(NPV) of pANCA,ASCA and their combination were analyzed.Results:Serum pANCA level was significantly higher in UC group than that in CD group and healthy controls [(584.22±347.70) pg/ml vs.(304.99±211.10) pg/ml and(390.92±82.82) pg/ml,P0.01],so was the positivity rate of pANCA(50.0%vs.14.5%and 14.3%,P0.01).The level and positivity rate of serum ASCA among these three groups had no significant difference.The sensitivity,specificity,PPV and NPV of pANCA~+and pANCA~+/ASCA~-in diagnosis of UC were 50.0%,85.7%,80.0%,60.0%and 42.2%,89.3%,81.8%,57.5%,respectively,and those of ASCA~+and ASCA~+/ pANCA~-in diagnosis of CD were 8.1%,87.5%,41.7%,46.2%and 3.2%,91.1%,28.6%,45.9%,respectively. Conclusions:Positive pANCA favors the diagnosis of UC.Detection of pANCA together with ASCA is helpful for the differential diagnosis of UC,but is not of high value for the diagnosis of CD.