FLAER Reagent for Flow Cytometry-Based PNH Screening

FLAER is an Alexa Fluor® 488 labeled variant of aerolysin, a unique protein that binds tightly and specifically to mammalian GPI anchors. FLAER will not bind to PNH cells because they do not produce the anchor. Before FLAER, detection of PNH clones by flow cytometry relied on fluorescently labeled antibodies to GPI-linked proteins such as CD59 and CD55. These antibodies do not bind with high affinity, so that small PNH clones are not detected. Also, they Each screen for the absence of a specific protein, rather than loss of the GPI anchor, and therefore there is the risk of false negative results. Since FLAER binds to the GPI anchor itself, only PNH cells, which lack the anchor, will be negative. And since FLAER binds with high affinity, very small PNH populations can be detected.