Clinically relevant functional flow cytometry assays.

As a lymphocyte proceeds along the pathway of cell division from the very earliest events of receptor aggregation-kinase activation to the final physical process of cell division, several physiologic functions occur, which can be measured by flow cytometry. Many of the functions along this pathway can be induced and measured in vitro and have led to the development of clinically relevant tests, which have been reviewed as functional flow cytometry procedures. It must be noted, however, that in addition to all of the physiologic processes that occur in lymphocytes (and in fact most cells) along the pathway to proliferation there are also several differentiated immune functions that are subject to flow cytometric analysis. Procedures for the evaluation of immune functions, such as phagocytosis, cellular aggregation, natural killer-cell cytotoxicity, cytokine secretion, antibody secretion, and antigen-specific cellular cytotoxicity assays have all been described.