The Inab phenotype: characterization of the membrane protein and complement regulatory defect.
Recent demonstration that Cromer-related human blood group antigens reside on decay-accelerating factor (DAF) has led to identification of an apparent null phenotype (Inab) for erythrocyte DAF. This study examined expression of other phosphatidylinositol (PI)-anchored proteins by Inab erythrocytes and showed that the PI-linked membrane proteins acetylcholinesterase (AchE) and lymphocyte function-associated antigen-3 (LFA-3) are normally expressed by these cells. Furthermore, studies of the complement sensitivity of Inab RBCs demonstrated them to be abnormally complement sensitive, with an apparent defect in downregulation of C3 convertase activity. Thus, the Inab phenotype appears to represent an instance of hereditary erythrocyte DAF deficiency whose mechanism differs from that of paroxysmal nocturnal hemoglobinuria (PNH) and which is unassociated with clinically evident hemolytic disease.
Telen
M J
MJ
Department of Medicine, Duke University Medical Center, Durham, NC 27710.
Green
A M
AM
D000110:Acetylcholinesterase / Q000097:blood; D000936:Antigen-Antibody Complex; D000954:Antigens, Surface / Q000097:blood; D001789:Blood Group Antigens; D018958:CD55 Antigens; D018968:CD58 Antigens; D003165:Complement System Proteins / Q000502:physiology; D004905:Erythrocyte Aging; D004910:Erythrocyte Membrane / Q000502:physiology*; D006801:Humans; D008562:Membrane Glycoproteins / Q000097:blood; D008565:Membrane Proteins / Q000097:blood / Q000172:deficiency* / Q000502:physiology; D010716:Phosphatidylinositols / Q000097:blood
D000936:Antigen-Antibody Complex; D000954:Antigens, Surface; D001789:Blood Group Antigens; D018958:CD55 Antigens; D018968:CD58 Antigens; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D010716:Phosphatidylinositols; D003165:Complement System Proteins; D000110:Acetylcholinesterase