Investigation of the survival of paroxysmal nocturnal hemoglobinuria red cells through the immunophenotyping of reticulocytes.
BACKGROUND
Complement-mediated lysis of red cells (RBCs) is a classic feature of paroxysmal nocturnal hemoglobinuria (PNH) that is traditionally studied with a combination of radiolabeling of RBCs and in vitro hemolysis tests. Phenotyping of reticulocytes was used as an alternative method for the evaluation of the relative life span of normal RBCs (PNH I) and RBCs that were partially (PNH II) or completely (PNH III) deficient in CD59.


METHODS
Murine monoclonal antibodies CD55, CD58, and CD59 and thiazole orange were used to phenotype reticulocytes by two-color flow cytometry in nine PNH patients. RBC survival could be calculated from the ratio of CD59- or CD59low mature RBCs to CD59- or CD59low reticulocytes obtained from these patients who had not received a transfusion.


RESULTS
The life span of PNH III RBCs varied from about 17 to 60 days. PNH II reticulocytes were found in the four patients with PNH II RBCs. The life span of PNH II RBCs varied with their residual expression of CD59, and cells with 15 to 20 percent of the normal amount of CD59 were protected against in vivo hemolysis.


CONCLUSIONS
Phenotyping of reticulocytes is a convenient and reliable tool for evaluating the relative survival of normal and PNH RBCs. PNH II and PNH III reticulocytes are phenotypically distinct, and some PNH II RBCs may be sensitive to complement-mediated lysis in vitro, but normally they are complement-resistant in vivo.
Navenot
J M
JM
Etablissement de Transfusion Sanguine Loire Atlantique-Vendée, Site de Nantes, France.
Muller
J Y
JY
Blanchard
D
D
D018958:CD55 Antigens / Q000097:blood; D018968:CD58 Antigens / Q000097:blood; D018957:CD59 Antigens / Q000097:blood; D004905:Erythrocyte Aging / Q000502:physiology*; D004912:Erythrocytes / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006457:Hemoglobinuria, Paroxysmal / Q000097:blood* / Q000145:classification; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D012156:Reticulocytes / Q000276:immunology*
D018958:CD55 Antigens; D018968:CD58 Antigens; D018957:CD59 Antigens