'VA', a new type of erythrocyte polyagglutination characterized by depressed H receptors and associated with hemolytic anemia. II. Observations by immunofluorescence, electron microscopy, cell electrophoresis and Biochemistry.

With help of immunoflorescence, best with anti-AHP from Helix pomatia, a stippled structure could be demonstrated on the patient"s red blood cells. Thus an "A-like" receptor could be detected on the erythrocyte membrane of this group O patient. The reactive antigen was proved not to be a crypt antigen exposed by the action of neuraminidase. The same stippled fluorescence with antiAhp was observed on the red blood cells of a patient suffering from hemolytic anemia induced by influnza A2 virus. In this case this virus was shown not to be responsible for polyagglutination. No virus or microorganism could be isolated from the patient"s blood. Also by immunofluorescence the weak expression of the H antigen could be demonstrated with an extract of Evonymus europaeus. Electron microscopy of erythrocytes was normal. The neuraminic acid content and the electrophoretic mobility were found to be decreased to a minor degree. No distinct cell populations could be observed.