Immunostaining of RBC membrane proteins from AC and AL erythrocytes. The Rh50 glycoprotein carries a N-linked polylactosylaminyl carbohydrate chain and is shown as a diffuse band of 45 to 75 kD in the RhD-positive control (Ctrl) using an antibody directed against the Rh50 N-terminus. No signal was detected in both AC and AL. All samples exhibited equivalent amounts of p55.