Production of allo-anti-Ena by an individual whose red blood cells carry some Ena antigen.

We recently described an individual whose red blood cells appear to carry a hybrid MNSs sialoglycoprotein (SGP). The MN-derived portion of that SGP carries at least two determinants defined by some examples of antibodies that have been called anti-Ena. However, the red blood cells lack a different determinant that is defined by other examples of anti-Ena. This individual has now formed an anti-Ena antibody that reacts with the portion of Ena that her red blood cells lack, but not with the Ena determinants that have been shown to be carried on MN SGP. It is not yet clear whether the portion of Ena that her red blood cells lack and that her antibody defines is MN SGP-borne. The findings in this case provide further support for our conclusions that the terms "Ena" and "anti-Ena," as previously used, describe heterogeneous groups of antigens and antibodies.