Background: Initial symptoms of inflammatory bowel disease in children are often less noticeable than they would be in adults and, even once noticed, may be misinterpreted. Diagnostic delay increases the risk of complications such as growth and pubertal disturbances or subnormal bone mineral density. Quality of life is impaired. The investigation of serological markers of IBD may to help prevent diagnostic embarrassments. Aim of the study: Assessment of the sensitivity and specificity of investigation of Saccharomyces cerevisiae antibodies (ASCA) and anticytoplasmatic neutrophils antibodies (pANCA) in children with IBD. Patients: 23 patients with Crohn’s disease with an average age of 15.7 years, 16 patients with ulcerative colitis with the average age of 13.2 years plus 30 controls. Methods: CD and UC were diagnosed in accordance with diagnostic criteria. IgA and IgG ASCA were investigated using the ELISA method (Medipan Diagnostica), IgG pANCA were investigated using the indirect immunoflorescence method (The Binding Site Birmingham, Great Britain) and the ELISA method (Trinity Biotech Jamestown, USA). Results: Positivity of IgA ASCA was found in 17 CD patients (73.9%), in 4 UC patients (25%) and in none of the controls. IgG ASCA positivity was present in 23 Crohn’s disease patients (56.6%), in 1 UC patient (6.3%) and in 1 control (3.3%). IgA ASCA serum levels were significantly higher in CD patients (92.3 U/ml) as compared to UC (22.4 U/ml) and controls (11.0 U/ml). Conclusion: Despite the limited sensitivity of serologic markers of IBD in children (IgA ASCA in CD 73.9 % and pANCA in UC 56.5 %) the specificity is high (IgA ASCA in CD 100 % and pANCA 96.7 % in UC). These methods may provide valuable information for the diagnosis of IBD in children.

        Key words: Crohn’s disease – ulcerative colitis –ASC A –pANC A