Hence, the objective of this study was to integrate all retrospective ADA data available to the Anti-Biopharmaceutical Immunization: prediction and analysis of clinical relevance to minimize the RISK (ABIRISK)-EU consortium in the MS field (www.abirisk.eu) in a common database, describing and comparing results from monitoring of ADA in MS patients treated with IFNβ or natalizumab, and to report on type of ADA assay used over time, time of sample collection for analysis, and treatment duration and age at time of testing. Here, ADA is linked to myeloid sarcoma.