Finnish En(a‐) Propositus with Anti‐EnaFS and Anti‐EnaFR: In vitro and in vivo Characteristics

Abstract
A third Finnish En(a-) individual (ERP) with alloanti-Ena has been identified. Subsequent family studies revealed that ERP is distantly related to the 2 previous Finnish En(a-) propositi. Serologically, ERP''s erythrocytes were found to be M-N-''N''+S-s+U+En(a-)Wr(a-b-) and were sialic acid deficient. SDS-PAGE studies confirmed that the red cell membranes lacked the MN-sialoglycoprotein, glycophorin-A. ERPs serum contained an IgG antibody which demonstrated two separable specificities, a ficin-sensitive specificity (anti-EnFS) and a ficin-resistant specificity (anti-EnFR), which reacted by the indirect antiglobulin technique. The antibodies were probably pregnancy induced, as ERP had never been transfused. A 51Cr-labelled red cell survival study showed that the antibodies were capable of causing signficant destruction of incompatible red cells.