Figure 1.
An example of peripheral blood phenotyping in paroxysmal nocturnal haemoglobinuria (PNH). Plots from a flow cytometer showing the clear discrimination between populations of normal and PNH cells in a patient's peripheral blood sample. (A,B) Plots showing the three types of red blood cells that can be detected in these patients. Type 1 cells are normal, type II are partially deficient in glycosyl phosphatidylinositol (GPI) linked proteins, and type III are wholly deficient. CD55 and CD59 are GPI linked antigens found on red blood cells. (C) Plot showing granulocytes that have been dual stained with two GPI linked surface antigens (CD16 and CD66) in a patient with PNH. This clearly delineates the normal and the PNH cells. (D) Plot using the same double staining method but with antigens relevant to monocytes (CD64 and CD14): the same clear demarcation is shown. Courtesy of Dr S Richards, Haematological Malignancy Diagnostic Service, The General Infirmary, Leeds, UK.