Ohem J, et al. – This study was performed to ascertain the association of infliximab (IFX) levels and antibodies to IFX (ATIs) with disease activity in a paediatric population. In terms of the association between IFX and ATIs as well as between IFX and disease activity, the paediatric population was similar to adult populations.

• Blood, stool, and clinical data from 65 patients (age 10.5-15.1 years) with Crohn's disease (CD) before IFX administration were prospectively collected.
• The physicians measured IFX trough levels, ATIs, and faecal calprotectin levels (CPT).
• They collected samples during maintenance therapy.
• Multivariate analysis was used to identify the predictors of IFX levels.

• In this study, lower levels of IFX were correlated with ATIs positivity (OR 0.027, 95% CI 0.009-0.077).
• The physicians found higher C-reactive protein (CRP) level, erythrocyte sedimentation rate, and CPT levels in patients with lower IFX levels.
• Using CRP level <5 mg/L as a marker of laboratory remission, the optimal combination of sensitivity (0.5) and specificity (0.74) for disease activity was calculated for IFX levels ≥1.1 μg/mL.
• The optimal IFX trough level was 3.5 μg/mL in a model that used CPT ≤100 µg/g as the definition of remission.
• They found no independent relationship between remission and ATIs in this study population.
• However, an independent relationship between IFX levels and serum albumin levels was found (OR 1.364, 95% CI 1.169-1.593), p < 0.001.