Biological analysis:
Blood samples were collected from all patients in the hospital: IFX patients were collected just before their infusion, and ADA patients were called to the hospital 24h before their injection.
An aliquote of serum and plasma was stored at -80°C. ADAbs and trough serum concentration of the biologics were measured by an Enzyme Linked Immunosorbent assay (ELISA) (Lisa-tracker, Theradiag®).
The threshold of detection of IFX and ADA was 0.1µg/ml. ADAbs were considered positive > 10 IU/ml.