Interferencias por terapia con anticuerpos monoclonales en electroforesis e inmunofijación de proteínas séricas

Abstract

IntroductionMonoclonal antibody therapy is being used nowadays to treat many diseases. Due to the structural similarity to endogenous immunoglobulins, they might be detected while testing for serum proteins using immunifixation and electrophoresis techniques, giving as a result false positives and being reported as monoclonal components mistakenly. ObjectivesTo reproduce rituximab, infliximab and tocilizumab serum concentrations in vitro and to evaluate the interference of these drugs when performing protein electrophoresis and immunofixation with agarose gel electrophoresis. Methods and materialsThe amounts of drug needed in order to achieve decreasing concentrations of monoclonal antibody were added to sera samples taken from healthy individuals. Both serum protein electrophoresis and inmunofixation were performed into those drug dilutions using IINTERLAB G26 as equipment. Results and conclusionsThe electrophoresis was positive for high drug concentrations in the three monoclonal antibody groups, being the signals weaker with decreasing concentrations. Same result was obtained with immunofixation, noting a band corresponding to a kappa G immunoglobulin which migrates closer to the cathode for the cases of rituximab and tocilizumab than for infliximab. It has been proved that rituximab, infliximab and tocilizumab are detected by agarose gel electrophoresis and their corresponding immunofixations and may cause false positives while detecting monoclonal components. Professionals should know the electrophoresis and immunofixation patterns of the monoclonal antibody drug used in their workplaces in order to avoid reporting false positives.