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P281. Anti-GP2 antibodies in children with Crohn's disease receiving infliximab

L. Miroshkina1, S. Petrichuk1, D. Roggenbuck2, E. Tsimbalova3, A. Potapov3, I. Zubkova4, A. Toptigina5, O. Kurbatova1, E. Semikina4, A. Anushenko3, E. Kapustina1, Z. Dukhova1, 1Scientific Centre of Children Health, Cytochemical laboratory, Moscow, Russian Federation, 2Lausitz University of Applied Sciences, Faculty of Natural Sciences, Senftenberg, Germany, 3Federal State Budgetary Institution “Scientific Centre of Children Health”, Gastroenterology and Hepatology, Moscow, Russian Federation, 4Scientific Centre of Children Health, Central Clinical laboratory, Moscow, Russian Federation, 5Moscow Scientific Research Institute of Epidemiology and Microbiology after G.N. Gabrichevsky, Laboratory of cytokines research, Moscow, Russian Federation

Background

It was shown that Anti-GP2 antibodies values are different in patients with distinct Crohn's disease (CD) phenotypes and various disease locations. The aim of the study was to investigate Anti-GP2 antibodies concentrations in children at different stages and duration of CD and various effects of anti-TNF-α therapy.

Methods

We measured circulating anti-GP2 IgG and IgA levels in 55 children with CD, aged from 6 to 18 years. There were 31 children, treated with infliximab. Anti-GP2 IgG and IgA values were tested in serum samples of children with CD by a commercial ELISA (Generic Assay, Dahlewits, Berlin, Germany), according to the manufacturer's instructions. All statistical tests were performed using nonparametric criteria (Mann–Whitney test). The measured values were expressed as medians with lower and upper quartiles.

Results

Anti-GP2 IgA values were significant higher in children at active phase of CD (N = 56) than in patients at remission (N = 18) - 9.4 (3.7–12.1) U/ml vs 4.1 (3.1–6.8) U/ml. Serum levels of anti-GP2 IgA were significantly higher in patients with severe onset of the disease compared with children with mild onset [10.0 (4.3–12.5) U/ml vs 4.2 (3.0–6.6) U/ml] regardless of exacerbation and remission stages. Children who suffered from CD more than 5 years had higher serum levels of anti-GP2 IgG (p < 0.005) than patients with less disease duration. It was revealed a tendency of gradual anti-GP2 IgG level increase with the course of CD. Comparison of anti-GP2 IgG and IgA levels in children with L1, L2, L3 locations of CD showed that children with L3 location had the highest antibodies values, the lowest levels were observed in patients with L1 location. Analysis of anti-GP2 antibodies levels in CD children under infliximab therapy showed that children with nonsustained efficacy of infliximab (6 weeks treatment) had significant higher both anti-GP2 IgA and IgG concentrations before the treatment than children with sustained effect of such therapy: anti-GP2 IgA 10.6 (5.6–17.4) U/ml vs 4.4 (1.9–7.5) U/ml; anti-GP2 IgG 14.0 (5.5–16.6) U/ml vs 4.2 (3.9–5.4) U/ml. Patients with nonsustained efficacy of infliximab demonstrated slow increase of anti-GP2 antibodies content during the therapy.

Conclusion

Children with moderate to severe activities and acute onset of CD had higher anti-GP2 IgA levels, than other patients. Serum levels of anti-GP2 IgG were significant higher in children with disease duration more than 5 years. Children with nonsustained efficacy of infliximab had significant higher both anti-GP2 IgA and IgG concentrations before the treatment than children with sustained effect.