FLAER Unconjugated

FLAER is a unique protein that binds tightly and specifically to mammalian glycol-phosphatidylinositol (GPI) anchored proteins on the cell surface. In healthy individuals, FLAER binds to essentially all GPI-expressing human lymphocytes, monocytes and granulocytes. White blood cells in a PNH patient losses expression of the GPI anchored cell-surface protein and FLAER fails to bind to lymphocytes, monocytes and granulocytes in a PNH patient. It is possible to detect the PNH clones by flow cytometry using fluorescently labeled antibodies to other GPI-linked proteins such as CD59 and CD55. But these antibodies have low binding affinity to GPI anchored surface antigen and confirmation of the presence of PNH clones was difficult as they often showed false negative results. Due to the high binding affinity of FLAER to the GPI anchor itself, only PNH cells, which lack the GPI anchored surface protein, will be negative and thus provides confirmatory results of the presence of PNH clones.