Multiplex analysis allows measurements of a large number of analytes simultaneously in each sample. On the basis of the Luminex multiplex technology (xMAP), kits for measuring multiple cytokines and chemokines (immunomodulators) are commercially available and are useful in investigations on inflammatory diseases. This study evaluated four multiplex kits (Bio-Plex, LINCOplex, Fluorokine, and Beadlyte) that contained 27, 29, 20, and 22 analytes each, respectively, for the analysis of immunomodulators in plasma of patients with rheumatoid arthritis (RA) who underwent treatment with antibody against CD20 (rituximab), a B-cell reductive therapy.
Multiplex kits were tested on serial plasma samples obtained from six RA patients at baseline and multiple time points (3, 6, and 9 months) post-treatment with rituximab. The RA patients included in this study had previously failed therapy with disease modifying anti-arthritis drugs (DMARD) and treatment with anti-TNFalpha antibody (infliximab).
Computer modeling and hierarchical cluster analysis of the multiplex data allowed a comparison of the performance of multiplex assay kits and revealed profiles of immunomodulators in the RA patients.
In plasma of RA patients who appeared to have benefited from the rituximab treatment, the profile of significantly elevated immunomodulators by at least two of the three kits (BioPlex, LINCOplex, Beadlyte) is as follows: IL-12p70, Eotaxin, IL-4, TNFalpha, Il-9, IL-1beta, IFNgamma, IL-10, IL-6, and IL-13. Immunomodulator profiling by multiplex analysis may provide useful plasma biomarkers for monitoring response to B-cell reductive therapy in RA patients.