Flow Cytometry Multiplex Bead Array Technology and Its Immunological Clinical Applications in Covid-19 Era

A thorough functional evaluation of the immune system requires a method capable of measuring multiple cytokines to assess the adaptive immune response, as well as immunoglobulin isotypes and seroconversion to evaluate the humoral immune response following infections and vaccinations. Flow Cytometry Multiplex Bead Array (FCMBA) technology has been shown to be highly effective in detecting and quantifying numerous analytes simultaneously in a single reaction well. This technique is increasingly being used in immune profiling for cytokines in various disease contexts, as well as in adoptive cell transfer, immunotherapies, and more recently, in the characterization of humoral responses to newly developed COVID-19 vaccinations. FCMBA technology has shown advantages in assessing the depth of the humoral response mounted against COVID-19 vaccinations, compared to post-COVID infection status, and screening for the suitability of sera for use in COVID-19 convalescent plasma therapy. In this article, we present an overview of the FCMBA technology concept and its versatility, highlighting its ability to map many essential analytes and its superiority over conventional Enzyme Linked Immunosorbent Assay (ELISA) techniques. Furthermore, we discuss the current and potential clinical applications of this technology in deciphering COVID-19-triggered humoral immune responses, whether after contracting the infection or post-vaccination.