Surface Ultramicroscopy of Paroxysmal Nocturnal Haemoglobinuria Erythrocytes

Survival and Significance of PNH Erythrocytes: a Scanning Study

“…Present SEM images of PNH red cells resulted quite similar to those previously reported [6,8], although the past studies had not paid too much attention to the presence of swollen cells in the PNH erythrocyte pool. Likewise, any relationship between percentage of PNH abnormal erythrocytes and severity of the haemolytic disorder was strictly refused [6,8].…”

“…On the other hand, re cent scanning electron microscope (SEM) studies [6,8] reported the pres ence in PNH erythrocytes of (a) marked variations in cell size, due to the high reticulocyte counts; (b) numerous thalassaemia-like target cells, with a prominent protuberance raising from their concavity; and (c) pits and deep craters, on the surface of most deformed elements. However, no cor relation could be stated between frequency of altered erythrocytes and se verity of the haemolytic disorder [6,8], By means of the SEM, the ideal tool for investigating cell surfaces, in the present study the problem of PNH erythrocytes has again been consi dered, in the attempt to evidence nature and degree of red cell alterations, as well as the occurrence of a possible relationship between such deforma tions and severity of the haemolytic disorder. Such problem may be tackled (a) by inducing PNH red cell haemolysis with mechanisms sim ilar to those occurring in vivo, (b) by testing different complement-sen sitivity of red cells with progressively decreasing serum dilutions, and then (c) by evidencing with SEM the features of the cells which survive in any dilution.…”

Membrane Abnormalities of Paroxysmal Nocturnal Hemoglobinuria (PNH) Red Cells and PNH-like Red Cells

“…Some authors have reported that the craters, pits and protuberances are found in PNH red cells by scanning electron microscopy (Lambertenghi et al 1970; Lewis et al 1971). These morphologic abnormalities were not seen in this study.…”

Normal Human Red Cells Treated in vitro with Cephalothin

“…The two kinds of lesion may be the expression of a cell damage of different degree, perhaps reflecting a different sensitivity of the erythrocytes to the drug. Although not so numerous as in cephalothin-treated erythrocytes, protuberances have been described in various conditions: newborn [12] and splenectomized subjects [12], patients with autoimmune haemolytic anaemia [14] and paroxysmal nocturnal haemoglobinuria [9]. Moreover protrusions have been observed in erythrocytes treated in vitro with sodium fluoride to inhibit glycolytic capa bility and produce deficiency of ATP, that is essential for the maintenance of normal membrane structure and deformability [I], On the other hand, a morphologic picture characterized by so numerous tiny projections has been observed in other conditions.…”

“…paroxysmal nocturnal haemoglobinuria (PNH) erythrocytes and normal red cells treated with the sulfhydryl compound AET (2-aminoethylisotiouronium bromide) (PNH-like cells). Both types of cells, similarly to cephalotin-treated erythrocytes, are abnor mally sensitive to the lytic action of complement [13,15,16,19] and display low acetylcholinesterase activity [4,18], However the aspect ofPNH and AET red cells is different from that of cephalotin-treated erythrocytes; in fact PNH red cells present protuberances, pits and craters on the surface [9] and AET cells appear completely deformed and show pronounced abnormal depres sions (unpublished observations). Although differences in appearance could reflect artifacts verified during specimen preparation rather than a different membrane alteration, the above suggests that cells that give similar serologic reactions can have a completely different morphologic appearance under the scanning electron microscope.…”