P187 MRI T2 relaxometry to image fibrosis in patients with Crohn's disease

(153.6±6.9 c.u. vs 108.3±3.9 c.u.). The ration between B1and B2-cells SDH activities characterized with 3 times B1-cells activity domination compared with control group (80% vs 20%). B-cells SDH activity and their number gradually decreased with increasing duration of the disease, mainly by virtue of the B2-cells parameters change. After the year of infliximab therapy it was observed significant B1-cells number augmentation in patients with nonsustained efficacy of the therapy (16% before 1 infusion vs 26.6% after 1 year). Moreover the period of infliximab tolerance development corresponded to B1-cells SDH activity augmentation. Patients with sustained infliximab therapy efficacy had higher B2-cells SDH activity compared with patients with nonsustained effect (113.0±3.2 c.u. vs 94.1±2.7 c.u.). Conclusions: Children with IBD were characterized with increase SDH activity of circulating B1-lymphocytes. Patients with nonsustained effect of infliximab therapy demonstrated gradually circulating B1-cells number increase along with B2-cells mitochondrial activity depression. The period of infliximab tolerance development corresponded to B1-cells SDH activity augmentation.