Figure 13

An inclusion body positive cell seen in Brilliant Cresyl Blue stained red cells of a α⁰-thalassaemia carrier. Inclusion Bodies are β4-tetramers precipitating on the red cell membrane, which damages the membrane and induces haemolysis. HbH is unstable and inclusion body positive cells are more difficult to find in older blood samples. The number of inclusion body cells seen after staining is much lower in α⁰-thalassaemia carriers than in patients with HbH disease (1 in 5-10 fields versus several per field at 1000× microscopic magnification).