Abstract
Serum cytokine profiling is a powerful tool to link host immune defense with disease pathogenesis. Although several multiplex assays are commercially available, none has been rigorously validated in the context of chronic infectious disease (such as HIV infection). Here we compared the measurement of proinflammatory cytokines by two multiplex platforms: the Meso Scale Discovery (MSD) electrochemiluminescence assay and the Becton Dickinson Cytometric Bead Array (CBA) flow cytometric assay, using serum samples from HIV-infected and -uninfected donors. We evaluated the ability of these assays to: a) quantify circulating levels of native cytokines (IL-6, IL-8, IL-10, TNF-α, IL-12p70, IL-1β), and b) accurately recover known amounts of recombinant cytokines added to serum samples. Based on the standard curves, the sensitivity of the MSD system was only slightly better than the CBA. However, in serum the MSD platform consistently quantified levels of endogenous IL-12p70, TNF-α, and IL-10 that were undetectable by the CBA assay. The MSD assay was also more accurate as determined by an enhanced capacity to recover known concentrations of recombinant cytokines added to serum. Both assays performed equally well in quantifying IL-6 and IL-8, while neither assay quantified IL-1β with accuracy and precision. Interestingly, HIV infection did not affect the performance of either assay. Overall, the MSD assay provided a more reliable assessment of the proinflammatory cytokines tested in the serum of healthy and HIV-infected individuals.