Diagnostic markers of inflammatory bowel disease

CLASSICAL SEROLOGICAL MARKERS IN PEDIATRIC INFLAMMATORY BOWEL DISEASE IN BRAZIL

BACKGROUND

Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) and anti-Saccharomyces cerevisiae antibodies (ASCAs) have long been used to differentiate between Crohn's disease (CD) and ulcerative colitis (UC), more recently having been used as prognostic indicators.

OBJECTIVE

To determine the diagnostic accuracy of serological markers in the identification of pediatric CD and UC in Sao Paulo, Brazil, as well as to correlate those markers with characteristics demographic and clinical of these two diseases.

METHODS

Retrospective cross-sectional multi-center study involving pediatric patients with inflammatory bowel disease (IBD). We identified ASCAs serological markers and p-ANCA, correlating their presence with demographic and clinical data, not only in the patients with IBD but also in a group of age-matched gastrointestinal disease-free controls.

RESULTS

A total of 122 patients, 74 with IBD (46% males), treated at four pediatric gastroenterology referral centers, the mean age of 13±7 years, 49 (66%) with CD, and 25 (34%) with UC. The control Group comprised 48 patients (54% males). The proportion of patients testing positive for p-ANCA was significantly higher in the UC group (69.9%) compared to the CD group (30.4%), as well as being significantly higher in the CD group versus the control Group (P<0.001 for both). The proportion of patients testing positive for ASCA IgA (76.2%) and ASCA IgG (94.4%) markers was also significantly higher in the CD group than in the control Group (P<0.001), and such positivity correlated significantly with the use of immunomodulatory medications such as azathioprine and anti-tumor necrosis factor agents (azathioprine 38.9%, anti-TNF 55.6%; P=0.002). In the CD group, the proportion of patients testing positive for the ASCA IgA was significantly higher among those who underwent surgery than among those who did not (26.86±17.99; P=0.032).

CONCLUSION

In pediatric patients with IBD in Sao Paulo, Brazil, serological tests proving to be highly specific, although not very sensitive, for the diagnosis of IBD. However, the serological markers showed a positive correlation with the severity of the disease.

Evaluation of colitis: usefulness of CT enterography technique

Computed tomographic enterography (CTE) is a useful technique for evaluating the small bowel and has the capability to include the colon for evaluation of patients with inflammatory bowel disease (IBD). The aims of this study are (1) to determine if CTE is a sensitive method for detecting Crohn colitis and ulcerative colitis and (2) to assess the accuracy of determining the extent and activity of colonic disease in patients with proven IBD. Seventy patients (35 patients with proven colitis at colonoscopy and 35 negative patients with a proven normal colon) having both a CTE examination and recent colonoscopy formed the retrospective study group. A radiologist evaluated the examinations in a blinded fashion for disease presence, activity, and extent. Sensitivity was 93% for the detection of moderate and severe disease in well-distended colons. Specificity was 91%. In good to excellent distended colons, mild, moderate, and severe disease was detected with a sensitivity of 67%, 90%, and 100%, respectively. Severe disease activity was commonly underestimated, and mild disease when detected was usually overestimated. The full extent of colonic disease at CTE was usually underestimated. CTE is a valid technique for detecting colitis in the colon in patients with IBD. Better methods for assessing disease activity and extent are needed.

Inflammatory bowel diseases: the paediatric gastroenterologist's perspective

Inflammatory bowel diseases (IBDs), including Crohn disease (CD) and ulcerative colitis (UC), often affect children and adolescents. Their diagnosis is based on the integration of clinical, biological, endoscopic, histological and radiological data. The paediatric radiologist may help the clinician in many ways. In children presenting with symptoms compatible with IBD, gut exploration by US may identify those who will benefit from more invasive explorations including endoscopy. During the process of diagnosis, small bowel exploration has a crucial role in differentiating CD from UC and in classifying the disease into subphenotypes. Finally, new imaging methods are useful during patient follow-up for assessing disease activity and for the diagnosis of complications.

Effects of surgery on peripheral N-terminal propeptide of type III procollagen in patients with Crohn's disease

AIM

This study investigates the effects of surgery on collagen turnover in patients affected by Crohn's disease (CD).

METHODS

Fifteen patients affected by active CD, assessed according to the Crohn's disease activity index, and confirmed by histology, with different pharmacological treatments, were enrolled in the study. N-Terminal propeptide of type III collagen was assessed on peripheral blood before and 6 months after surgery, as an index of collagen turnover. A control group of 15 healthy age- and sex-matched subjects was also studied.

RESULTS

In CD patients peripheral N-terminal propeptide of type III collagen serum levels were significantly higher than in controls before surgery (5.0 +/- 1.8 vs 2.7 +/- 0.7 microg/l, respectively; p = 0.0001). Six months after these values were significantly reduced (from 5.0 +/- 1.8 to 3.1 +/- 0.8 microg/l; p = 0.003). Independently on the pretreatment regimen and the duration of the disease, an improvement in the patients' symptoms was observed.

CONCLUSIONS

The surgical resection of the affected intestinal segment in CD patients seems to be able to break down the collagen synthesis processes. Peripheral N-terminal propeptide of type III collagen could be seen as an additive marker to clinical and endoscopic observations after surgery.

Clinical significance of anti-Saccharomyces cerevisiae antibody (ASCA) in Korean patients with Crohn's disease and its relationship to the disease clinical course

BACKGROUNDS/AIMS

The implications of anti-Saccharomyces cerevisiae antibody for the diagnosis and the clinical course of Crohn's disease have been reported in Western countries, but rarely in Korea with its very different environmental and genetic backgrounds. We aimed to evaluate whether anti-S. cerevisiae antibody expression is associated with diagnostic findings, stratified Vienna classification phenotypes, disease activity and clinical course in Korean patients with Crohn's disease.

MATERIALS/METHODS

One hundred and fifteen patients with Crohn's disease, diagnosed and treated between 1990 and 2004 at Severance Hospital, Yonsei University and followed for at least 2 years, were included in this study. Anti-S. cerevisiae antibody was detected by an indirect immunofluorescence assay using EUROIMMUN kits. Information collected during treatment included demography, Vienna classification phenotype, clinical manifestation, laboratory tests, treatment modality and surgery rate. Disease activity was measured monthly using the Harvey-Bradshaw index.

RESULTS

The anti-S. cerevisiae antibody prevalence was 38.3% in Crohn's disease patients. There was no difference in anti-S. cerevisiae antibody expression between genders. The mean age at diagnosis was younger for the anti-S. cerevisiae antibody positive group than the negative group (25.3 years versus 29.7 years, p<0.05). Clinical manifestations and laboratory tests at diagnosis did not differ between the groups. The anti-S. cerevisiae antibody positive group had increased fibrostenosis (B2) and penetration (B3) compared to negative group, as determined by the Vienna classification (75.0% versus 53.5%, p<0.05). Anti-S. cerevisiae antibody positive patients were admitted to the hospital more frequently than anti-S. cerevisiae antibody negative patients (p<0.05). The yearly cumulative Harvey-Bradshaw index score was higher in the anti-S. cerevisiae antibody positive group than in the negative group during the follow-up period (p<0.05). In addition, steroid (72.7% versus 52.1%, p<0.05) and immunosuppressive (45.5% versus 23.9%, p<0.05) treatments were more frequently given to the anti-S. cerevisiae antibody positive group.

CONCLUSIONS

Our data demonstrate that anti-S. cerevisiae antibody positive Crohn's disease patients had a more severe clinical course and thus often required more aggressive medical treatment.

Combined use of noninvasive tests is useful in the initial diagnostic approach to a child with suspected inflammatory bowel disease

OBJECTIVE

To assess the effectiveness of the combined use of fecal calprotectin (FC), anti-Saccharomyces cerevisiae antibody (ASCA), perinuclear staining antineutrophil antibody (pANCA), small intestinal permeability test (IP), and bowel wall ultrasonography measurement (BWUS) in the diagnostic work-up of children with suspected inflammatory bowel disease (IBD).

METHODS

All children referred for initial assessment of possible IBD were eligible. Patients with symptoms or signs (right-lower quadrant mass, perianal disease, or hematochezia) mandating a complete work-up for IBD were excluded. All enrolled patients underwent a clinical, laboratory, radiographic, and endoscopic evaluation including biopsy examinations. The immunoglobulin (Ig)G and IgA ASCA, IgG pANCA, FC, IP, and BWUS were tested in all patients at the initial assessment.

RESULTS

A final diagnosis of IBD was made in 27 patients: 17 Crohn disease and 10 ulcerative colitis. Eighteen children had other gastrointestinal diagnoses (8 functional bowel disorders, 5 food allergy-mediated diseases, 4 infectious enterocolitis, 1 familial Mediterranean fever). In patients with simultaneous abnormal values of FC, BWUS, and ASCA/pANCA, the estimated probability of having IBD was 99.47%. Patients with negative results on all tests had a 0.69% of probability of IBD.

CONCLUSIONS

The incorporation of noninvasive diagnostic tests into the initial diagnostic approach may avoid unnecessary invasive procedures and facilitate clinical decision-making when the diagnosis of IBD in children is initially uncertain.

Effects of disease activity on anti-Saccharomyces cerevisiae antibodies: implications for diagnosis and follow-up of children with Crohn's disease

BACKGROUND

To determine diagnostic accuracy of anti-Saccharomyces cerevisiae antibodies (ASCA) in identifying children with inflammatory bowel disease (IBD) and to differentiate Crohn's disease (CD) from other IBD forms; and to determine the effect of medical or surgical treatment and of disease location and activity on ASCA titers.

METHODS

Serum samples were obtained from 196 IBD children and 142 controls. ASCA IgA and IgG titers were measured by ELISA. Measurements were repeated during the follow up of CD children.

RESULTS

ASCA titers were significantly higher in CD than in other IBD and in control patients. Combination of IgA and IgG ASCA positivity was highly specific for CD. Medical treatment and disease location did not influence assay results. Significantly lower ASCA titers were obtained in CD children with intestinal resection compared to CD-affected children who did not undergo surgical resection. ASCA titers correlated significantly with disease activity, and children with severe active disease showed higher ASCA values compared to those in remission. A significant reduction of ASCA was observed during the follow-up of CD children when clinical remission was achieved.

CONCLUSIONS

The diagnostic accuracy of ASCA is influenced by disease activity and this suggests an additional use for the follow-up of CD children of this assay.