What are Heinz bodies?

Heinz bodies appear as small round inclusions within the red cell body, though they are not visible when stained with Romanowsky dyes. They appear more clearly when supravitally stained

Heinz bodies (also referred to as "Heinz-Ehrlich bodies") are inclusions within RBCs composed of denatured Hb.  

Heinz bodies are inclusions in red blood cells, they are caused by the denaturation of haemoglobin. Heinz bodies can be seen in cases of haemolytic anaemia.

Heinz bodies are cellular inclusions in a red blood cell that consists of damaged aggregated hemoglobin seen in patients with drug-induced oxidative damage, G6PD deficiency, unstable hemoglobins and with some forms of hemolytic anemia. “Bite cells” may be seen; produced by removal of Heinz bodies from red cells with damaged membranes by splenic macrophages. Heinz bodies are not visible on a Wright-Giemsa stain, must be visualized using supravital stains (e.g., methyl violet, crystal violet, brilliant green, or new methylene blue).

Heinz bodies are formed by damage to the hemoglobin component molecules, usually through oxidant damage, or from an inherited mutation (i.e. change of an internal amino acid residue). As a result, an electron from the hemoglobin is transferred to an oxygen molecule, which creates areactive oxygen species(ROS) that can cause severe cell damage leading to premature cell lysis.Damaged cells are cleared bymacrophagesin thespleen, where the precipitate and damaged membrane are removed, leading to characteristic "bite cells". The denaturing process is irreversible and the continual elimination of damaged cells leads toHeinz body anemia.