Microangiopathic haemolytic anaemia: the phenomenon of red cell adherence.

Examination by scanning electron microscopy of erythrocytes from three cases of microangiopathic haemolytic anaemia demonstrated the presence of adherent cells. Although in some cases this appeared to be due to a thin strand, presumably fibrin, between the erythrocytes, in most instances there was intimate contact and this was invariably associated with damage to the red cell surface membrane. It is considered that the adherence is predominantly due to altered physico-chemical properties of the surface membrane of the red blood cell and that further morphological abnormalities may result from the intravascular stresses to which the paired cells are subjected.