Relations between surface charge and in vitro lysis of red blood cells in paroxysmal nocturnal haemoglobinuria.

The effects of neuraminadase on the electrophoretic mobility and in vitro lysis of PNH, glutathione treated and normal erythrocytes was determined. Neuraminidase strongly affected the in vitro haemolysis of PNH and glutathione treated erythrocytes by substantially elevating the lysis in the Ham acid test while virtually eliminating lysis in the sucrose test. Findings suggest that membrane bound sialic acid or the level of cell surface charge may have a role in the susceptibility of PNH erythrocytes to complement mediated lysis.