Evaluation of a human anti-mouse antibody rapid test for patients requiring radio-immunodiagnostic.

Monoclonal antibodies (mAbs) play a significant part in the diagnostic and therapeutic arsenal. They are used in many fields of medicine, ranging from in vitro diagnosis to the treatment of multiple pathologies in such diverse areas as infectious diseases, immunology and oncology. The first mention of the use of radiolabeled antibodies dates from the 1950s. However, from the first tests, several problems with the use of radiolabeled antibodies appeared. One of these involved the use itself of the antibodies because they caused an immune response and the production of human anti-mouse antibodies (HAMAs) [1]. Complications related to this immunization are very rare and have a high inter-individual variability [2–4]. It is widely accepted that the presence of these heterophilic antibodies could influence the effectiveness of the immunotherapy and immunoscintigraphy, and could also be considered as responsible for analytical interference in immunoassays [5, 6]. Indeed, HAMAs bind to the newly administered mAbs, leading to the formation of immune complexes (HAMA-mAb) that may decrease the therapeutic efficacy and diagnostic value of the new mAb conjugates. Similarly, allergic reactions could occur, motivating the search for HAMAs before any reintroduction of mAbs [7]. Current tests for HAMA detection do not allow one to quickly obtain the status of patients. To develop a simple, rapid and reliable test for monitoring the presence of HAMA in some patients, Milenia GmbH (Hamburg, Germany) has recently proposed a new qualitative test based on the principle of a rapid lateral flow test on a strip. We proposed to evaluate this Quicktest on our cohort of patients who had tested positive for HAMAs using the quantitative Medac HAMA-ELISA test. Serum samples from patients positive for HAMA were obtained from a serum bank collected between 1992 and 1999 in the Nuclear Medicine Department of Grenoble University Hospital. The patients had received radioimmunotherapy and subsequently developed HAMAs demonstrated using the quantitative Medac test. Sera were estimated again in 2014 using the same test to verify the persistence of expression of HAMA. This test is a one-step enzyme immunoassay for the quantitative determination of HAMA in serum realized in 1 h. The test is calibrated against anti-mouse IgG antibodies. The measuring range is from 40 to 2000 ng/mL. Samples and peroxidase-labeled mouse IgG conjugate are added together to the plate that is pre-coated with mouse IgG (antigen). The HAMAs bind to the solid phase and to peroxidase-labeled mouse IgG. Then, there is an incubation step with a tetra-methyl benzidine substrate. The reaction is stopped by the addition of sulfuric acid, and the absorption is read photometrically at 450 nm. According to the manufacturer, the limit *Corresponding author: Marie-Dominique Desruet, PhD, PharmD, Radiopharmacy/ Nuclear Medicine Department, Grenoble University Hospital, CS 10217 38043 GRENOBLE cedex 9, France, Phone: + (0)33 476 769 410, Fax: + (0)33 476 767 108, E-mail: [email protected]; and Pharmacy Department, Grenoble University Hospital, Grenoble, France Chloé Lamesa: Pharmacy Department, Grenoble University Hospital, Grenoble, France; and UMR-S INSERM 1039 Bioclinical Radiopharmaceutical Unit, Grenoble, France Anne-Sophie Gauchez: UMR-S INSERM 1039 Bioclinical Radiopharmaceutical Unit, Grenoble, France; and Radioactivity Platform, Biology Department, Grenoble University Hospital, Grenoble, France Roseline Mazet and Luc Foroni: Pharmacy Department, Grenoble University Hospital, Grenoble, France Daniel Fagret: UMR-S INSERM 1039 Bioclinical Radiopharmaceutical Unit, Grenoble, France; and Nuclear Medicine Unit, Imaging Department, Grenoble University Hospital, Grenoble, France