Utility of serum antibodies in determining clinical course in pediatric Crohn's disease

Background & Aims: The utility of serial measurements of anti-Saccharomyces cerevisiae (ASCA) and perinuclear antineutrophil cytoplasmic (p-ANCA) antibodies in Crohn's disease (CD) evolution is unknown. We aimed to study the pattern of antibody change and the prognosis of selected outcomes by baseline (at time of diagnosis) and serial antibody measurements in pediatric CD patients. Methods: Serum ASCA and p-ANCA antibodies were measured at baseline (n = 154) and repeated during follow-up (n = 61) using standard techniques in a cohort of patients identified at Hôpital Sainte-Justine between 1996 and 1998. Clinical information was abstracted from medical charts. Antibody patterns were examined using mixed modeling techniques. The prognostic ability of antibodies for selected outcomes was evaluated using logistic regression. Results: Fifteen (24.5%), 18 (29.5%), and 11 (18%) patients with serial antibody measurements changed their ASCA-IgA, ASCA-IgG, and p-ANCA status (positivity), respectively. No distinct patterns in the evolution of antibody titers were noted. Baseline ASCA-IgA positivity significantly predicted relapses during disease course (IgA: odds ratio [OR], 2.9; 95% confidence interval [CI], 1.33-6.35). Serial antibody measurements did not predict the occurrence of clinical outcomes. Conclusions: Baseline serum antibodies were predictive of a more relapsing disease course in pediatric CD. However, the limited variability in the antibodies over time and the inability of serial measurements to predict clinical outcomes may limit their use in the establishment of intervention strategies.